# Which octane do you use in your 1.4T Cruze?



## StoneCrab (Sep 14, 2011)

What grade of gas do you regularly or most often choose for your 1.4T Cruze? 
Regular, mid-grade, or premium are the choices, since actual octrane numbers vary from state to state for the various level. Usually regular is 87 octane, mid-grade is 89, premium is 91-93.


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## DanRS (Aug 23, 2011)

regular.....and the cheapest i can find.


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## idrive1 (Oct 14, 2011)

I use regular all the time and have no problems using it.


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## FatKidsCruze (Sep 2, 2011)

Premium 93 from Shell or BP for me... I'll soon be Trifecta tuned and be required to use 93 anyway.


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## Vetterin (Mar 27, 2011)

I sure didn't buy a fuel miser to put premium in it!


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## sciphi (Aug 26, 2011)

Premium. It does get better fuel economy and power over regular unleaded.


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## Atomic (Nov 5, 2011)

Only Premium 93 from Shell/BP for me. Absolutely senseless to run a turbo-charged motor on regular 87 to save $2.00 per fillup.


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## tecollins1 (Nov 6, 2011)

When I first got my vehicle I ran one tank of 87 through it. I noticed more vibration from the engine at lower rpms. After that tank I went to 93 this has been my 3rd tank of 93 and the vibrations are pretty well gone. Have'nt really seen any mpg improvements as some have stated but I don't think you would notice it anyways.( since there are so many different variables that come in to play with mpg) I've been avg 31mpg do to 90% city/hills and 10% highway . 



Sent from my Autoguide iPhone 4 app


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## shawn672 (Oct 31, 2010)

I'm sad to see so many people running 87 when even GM confirmed you should run at least midgrade in the summer.. 89 should be a minimum year round though, its a lot safer and better for this platform than 87, it's a mere $1.00-1.50 more per fillup for better mileage, better timing (small bump in power), and safer for the forced induction motor


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## Quick10 (Aug 1, 2011)

shawn672 said:


> I'm sad to see so many people running 87 when even GM confirmed you should run at least midgrade in the summer.. 89 should be a minimum year round though, its a lot safer and better for this platform than 87, it's a mere $1.00-1.50 more per fillup for better mileage, better timing (small bump in power), and safer for the forced induction motor


Where did they say you should run 89? I never got notified about that.


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## MafiaLTZ11 (May 29, 2011)

93 all day, everyday. Every mile that I have driven. (Except for whatever the dealer put in)


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## ErikBEggs (Aug 20, 2011)

> I'm sad to see so many people running 87 when even GM confirmed you should run at least midgrade in the summer.. 89 should be a minimum year round though, its a lot safer and better for this platform than 87, it's a mere $1.00-1.50 more per fillup for better


IIRC, GM said 91 octane in extreme temperatures. In the northeast like me, your fine with 87 95% of the time.

I use 91 Octane because of the tune. Sunoco is pretty much the only retailer around that sells 91 instead of 93 (sells both!), and the Sunoco near me has it for only $.02 more than 89 octane which is a steal.


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## NBrehm (Jun 27, 2011)

I used 87 for awhile until I put 93 and the engine ran 10X better and got even better gas mileage. Now after the tune I don't have a choice


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## cruzers (Dec 13, 2010)

70AARCUDA said:


> ...exactly what the *Owners Manual *says to use, *87 octane*.


+1

Some people claim after a car wash, your car runs better, just like 93 octane.


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## shawn672 (Oct 31, 2010)

cruzers said:


> +1
> 
> Some people claim after a car wash, your car runs better, just like 93 octane.


except only one of these two was proven by GM to actually make a difference...


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## sciphi (Aug 26, 2011)

It looks like we have the enthusiasts/motorheads/tuners who are seeking every last HP/TQ/MPG from the engine, and the folks who are just fine with the power/fuel economy as is. I'm noting two different populations with different goals, who are acting differently. The enthusiasts are generally running premium, while everybody else is generally running regular. The engine is okay running regular. It runs better on premium. 

GM and a few auto magazines did prove the 1.4 does get better fuel economy in summer weather on premium. It was about 3 mpg IIRC. It was a large enough difference where it made up for the $2/tank extra for premium.


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## [email protected] (Nov 12, 2011)

Think of octane rating as a sort of "temperature" rating if you will. 

When you compress air, it gets hot. The higher the octane rating, the higher the temperature the air/fuel mixture can withstand before igniting on its own, without a spark plug firing. When this "pre-ignition" happens, you get knock. The higher the compression ratio is in the cylinder (either by using higher compression pistons/heads, or by using a power adder like turbo or supercharger), the higher the chance of this happening. Running a higher octane fuel in a higher compression scenario reduces the likelihood of this happening. 

Knock if severe enough will cause engine failure. 

This is why race engines use 110-116 octane fuel and why I don't agree with using anything below 91 in any forced induction motor. Sure you can run it, and the engine will sense the knock and pull timing to reduce the overall compression in the cylinder, but why risk it when the price difference is only like $2 per fill up?


Sent from my Autoguide iPhone app


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## toilet_monkey (Nov 30, 2011)

70AARCUDA said:


> ...exactly what the *Owners Manual *says to use, *87 octane*.


yep exactly. Guys, there's no risk in running 87 octane in your car.


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## cashmoves (Oct 14, 2011)

[email protected] said:


> Think of octane rating as a sort of "temperature" rating if you will.
> 
> When you compress air, it gets hot. The higher the octane rating, the higher the temperature the air/fuel mixture can withstand before igniting on its own, without a spark plug firing. When this "pre-ignition" happens, you get knock. The higher the compression ratio is in the cylinder (either by using higher compression pistons/heads, or by using a power adder like turbo or supercharger), the higher the chance of this happening. Running a higher octane fuel in a higher compression scenario reduces the likelihood of this happening.
> 
> ...


this ^. its not about one group of people wanting 'performance' and the other group thinking that since this is an economy car they want to squeeze every dollar out of their purchase by running garbage gasoline. its about taking care of your engine. if you want to take the best care of your car, then dont use garbage gasoline. GM says 87 is fine in the manual because its not going to ruin the engine BEFORE the warranty runs out. they know that a lot of people who dont know much about turbo engines will think its ridiculous if a 20k car which is advertised as a great economy choice requires you to use premium gasoline, so they just say 87 is 'fine.' yea, its 'fine' for GM because the risk TO THEM is not great enough to outweigh the reaction by their consumers.


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## StoneCrab (Sep 14, 2011)

Well, this is interesting. Roughly 50/50 regular versus premium. I expected this to be more lopsided. I would bet that the general population of Cruze owners outside this forum are much more lopsided to regular unleaded. I understand the technical details about octane its role in engine performance and knock. The two key questions for me are;

1. Does 87 octane pose a real risk of damage in a stock 1.4T motor?
I am somewhat uncomfortable running 87 octane in a turbo motor, for all the reasons shown so far in this thread. However, I trust that GM would not release an engine that would be harmed by 87 octane while specifying 87 octane in the manual. So I am inclined to believe that 87 octane is safe and harmless. Even NA low compression motors will knock sometimes and we don't see any rash of knock related engine failure in any modern engine, whether designed for performance or economy. 

2. Does usage of premium unleaded increase MPG? 
This seems to have a mixed answer - yes, maybe sometimes. Forum users have reported yes, no, and sometimes. GM has said that in extreme heat higher octane will prevent knock and reduced timing, leading to increased MPG. But outside of extreme heat, is there any difference on the stock tune? I would like to know if the engine routinely pulls timing while running 87 octane in low or normal ambient temp and engine load. If the stock tune is designed to safely run 87 octane then I doubt that there are alternate maps for high-octane - that is, assuming there is no knock on 87 octane then the ECM is oblivious to premium unleaded. 

Note that regular unleaded is not lower quality than premium unleaded at the same station. It simply has a lower octane rating. Premium unleaded may have higher ethanol content, thereby reducing its specific energy content relative to 100% gasoline and perhaps even to regular unleaded at the same station if ethanol is used to increase octane. It is purely a marketing technique to make people believe that premium unleaded is 'better', it just has higher octane.


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## feh (May 29, 2011)

I ran 87/89 the first 5 months we owned our Eco. Now using 91/93 due to Trifecta tune.


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## Macman (May 4, 2011)

Premium. better performance, better mileage, little actual difference in cost, actually comes out cheaper with better mileage, plus the same amount of gas in gallons lasts longer. 93 octane only.


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## TravsCruze (Aug 4, 2011)

93 E0 only, its out of my way, but I prefer it.


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## sciphi (Aug 26, 2011)

Some premium gasolines also have more detergents than regular. Shell at least used to advertise that their premium had more detergents than regular gasoline.


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## eagleco (May 3, 2011)

Interesting article about premium gas. I drive conservatively and for gas mileage, getting 44-46 on the highway and high 30's in town. A bit less now that it's winter and with just a 5 mile commute my car barely gets warmed up. Regular is all I use and with complete confidence.

USATODAY.com - Why use premium gas when regular will do?


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## Aeroscout977 (Nov 25, 2010)

eagleco said:


> Interesting article about premium gas. I drive conservatively and for gas mileage, getting 44-46 on the highway and high 30's in town. A bit less now that it's winter and with just a 5 mile commute my car barely gets warmed up. Regular is all I use and with complete confidence.
> 
> USATODAY.com - Why use premium gas when regular will do?


That article seems to think when some manufactures say "required" they mean "recommended". Also according to GMs Bob you only need premium if your car's Supercharged. So high compression and turbo chargers don't matter?


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## SilverCruzer (Nov 30, 2010)

Atomic said:


> Only Premium 93 from Shell/BP for me. Absolutely senseless to run a turbo-charged motor on regular 87 to save $2.00 per fillup.


Well...its also absolutely senseless to pay extra for fuel that will not improve performance of a MODERN turbo designed and calibrated to run on 87.
This debate has been killed and kicked too many times on this forum. We have had actual engineers and techs involved with the Cruze speak up and state 87 is best, and we also have had many users test both in controlled enviro's and see no difference.


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## Rotherd31 (Apr 5, 2011)

SilverCruzer said:


> Well...its also absolutely senseless to pay extra for fuel that will not improve performance of a MODERN turbo designed and calibrated to run on 87.
> This debate has been killed and kicked too many times on this forum. We have had actual engineers and techs involved with the Cruze speak up and state 87 is best, and we also have had many users test both in controlled enviro's and see no difference.


I couldn't agree more, but there will always be those that try to ride a dead horse !!!!!


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## shawn672 (Oct 31, 2010)

SilverCruzer said:


> Well...its also absolutely senseless to pay extra for fuel that will not improve performance of a MODERN turbo designed and calibrated to run on 87.
> This debate has been killed and kicked too many times on this forum. W*e have had actual engineers and techs involved with the Cruze speak up and state 87 is best*, and we also have had many users test both in controlled enviro's and see no difference.


Link please? I hope you're not referring to the half-pot "engineer" from GM who also said there wasn't free power and better transmission controls.. because we quite proved him wrong on even occasion.

And for those who realize how bad 87 is for this engine, we also have Trifecta who data logged and saw actual KNOCK occuring with 87 and ambient temps were not even that high.. granted in the winter you could probably get away with 87, from late spring to late fall you should be running 89/91 minimum. It's a whole $1-2 more per fillup, don't be cheap


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## cashmoves (Oct 14, 2011)

SilverCruzer said:


> Well...its also absolutely senseless to pay extra for fuel that will not improve performance of a MODERN turbo designed and calibrated to run on 87.
> This debate has been killed and kicked too many times on this forum. We have had actual engineers and techs involved with the Cruze speak up and state 87 is best, and we also have had many users test both in controlled enviro's and see no difference.


link please. first of all, i doubt this car was "designed and calibrated" to run on 87 when the car was designed for the world market and then brought over the US. you cannot find 87 garbage gasoline in many other parts of the world. if it was designed for anything it was most likely 93 and better. but again, thats just my conjecture.

id also like a link to the thread where Trifecta saw the knock occurring with 87 octane. it makes sense and im sure its accurate info, i think it would just be best to have it linked into this thread. some real data would help cut through the mess of uneducated opinions in this thread...


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## eagleco (May 3, 2011)

If 87 was truly "garbage gasoline", then the side of the road would be bumper to bumper with broken down cars. I have been driving for nearly 35 years now, and have only used premium in my Miata which had a high compression engine and was the specified grade. I can't think of a single mechanical problem, performance problem, or any other kind of problem that was "garbage gasoline" related in all my years of driving.

It's your money, if you think your car runs better, gets better mileage, or needs high octane gas that's fine, but where is the evidence that 87 octane is "garbage gasoline"

The formula for measuring octane ratings in Europe is different than the formula used in the US. A 95 octane in Europe is about the same as a 90 octane in the US. And that's why you cant find 87 "garbage gasoline" in Europe where the 1.4t was originally designed and built. A Google search will yield plenty of references on this point.


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## TekWarren (Aug 24, 2011)

I'm middle of the road right now. I logged several tanks of premium, now I am on mid, and will go back to 87 most likely. I don't "feel" a bit difference and my MPG is not changing enough to prove anything at this point. I also didn't buy my Eco as a street racer...It's a commuter car. I think there are a lot folks here who take the side of I'm right, your wrong. I don't see how running at either end of the spectrum is "wrong" or being "cheap" or "bad" or a "waste". These cars are marketed for fuel efficiency and affordability are they not? So why would a company design a car that runs better using one grade over another when the majority of the population who is not driving high end cars uses regular? Legitimate questions, I am not a mechanic... I just hate seeing sides "define" which is best making the average person sway one way or the other, it's gasoline...put it in your car and drive it, if your concerned about what to do consult your owners manual. If you follow the manual you shouldn't have to worry about warranty issues and such and your car should run fine.


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## eagleco (May 3, 2011)

TekWarren said:


> I just hate seeing sides "define" which is best making the average person sway one way or the other, it's gasoline...put it in your car and drive it, if your concerned about what to do consult your owners manual.


Good point. This gasoline issue is almost like talking politics or religion. Time to let this one go. Maybe we can all agree that it's nice to have a choice about what gas to use, and nobody will be persecuted for the choice they make.


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## shawn672 (Oct 31, 2010)

I will refer everyone to the SEARCH button as there have been at least two dozen topics with long threads on this, including links from GM reporting on the use of 89 and it's effects


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## eagleco (May 3, 2011)

Thank you Quazar for that link. It makes for interesting reading. Maybe next summer when it gets hot as it actually does in Minnesota, sometimes:smile:, I'll use 91 octane a bit. Don't think there is any point now when the ambient temp is pretty much stuck below freezing until spring:frown:.

Last summer I took a weekend road trip in hot (well 80 degrees anyway) weather. With the AC on, luggage in the trunk and my BBW girlfriend next to me, I was getting 44 mpg going 70 mph (verified the old fashioned way). If I can improve on that by running premium that would be something.


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## 70AARCUDA (Nov 14, 2010)

• *my simpleton summary*: use what the Owners Manual says (*87 octane*) *unless there's a darn good reason to use something higher-grade*, such as pulling a heavy load through the mountains during hot summer months, *THEN* use *91-* or *93-octane*, but _*only as long *_as the extraordinary driving conditions exist. Then, when you get to _"...Grandma's house in the mountains..."_, switch _*back*_ to *87-octane*.


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## mreese (Dec 7, 2011)

shawn672 said:


> Link please? I hope you're not referring to the half-pot "engineer" from GM who also said there wasn't free power and better transmission controls.. because we quite proved him wrong on even occasion.
> 
> And for those who realize how bad 87 is for this engine, we also have Trifecta who data logged and saw actual KNOCK occuring with 87 and ambient temps were not even that high.. granted in the winter you could probably get away with 87, from late spring to late fall you should be running 89/91 minimum. It's a whole $1-2 more per fillup, don't be cheap


LINK PLEASE!!!! lol you respond to one by asking for PROOF, only to give another example with out PROOF. Come on Trifecta, they want to sell you something, what do you think they are going to say!!
Before you go flaming me, I could careless who runs what. Frankly had not thought of what grade, now I will do my research on what GM recomends and probably run the Super. Yes I do understand engines , I played a mechanic in a play once.


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## Aeroscout977 (Nov 25, 2010)

mreese said:


> LINK PLEASE!!!! lol you respond to one by asking for PROOF, only to give another example with out PROOF. Come on Trifecta, they want to sell you something, what do you think they are going to say!!
> Before you go flaming me, I could careless who runs what. Frankly had not thought of what grade, now I will do my research on what GM recomends and probably run the Super. Yes I do understand engines , I played a mechanic in a play once.



What does Trifecta get out of telling people to run premium? Nothing. They have a tune for regular and premium. We've never had one issue of dishonesty from Vince and there's absolutely no reason to suspect it.

That being said as long as you're not operating in "extreme" conditions you are fine. Mind you a fully loaded car or city driving can be considered "extreme" to GMs criteria. In my personal opinion I would at least be running 89.


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## ErikBEggs (Aug 20, 2011)

If I wasn't tuned, I'd probably be running 87. GM wouldn't warranty something for 100,000 miles if it wasn't safe. After that is probably a different story.. but I guess they are counting on people not keeping the car too much past then..


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## shadyguy22 (Dec 3, 2011)

It said in the owners manual 87 octane, my buddy is a gm were I bought my cruze, and he said the same thing, higheroctane is kinda a spoof if you ask me.
I ran 87 ever since I purchased my cruze, took a trip from Colorado to las Vegas, 2 1/2 tanks roud trip, keep in mind I have the eco w/6speed manual trans. An i was getting 50+ mph on that trip.
So if you have upgrades to your cruze like a bigger turbo, ecm, etc. Than yes 91+ would be better, but for every day drivers than i would stick with the 87, an keep your factory warranty. LOL


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## speedy862004 (Dec 13, 2012)

I just got my Eco in the beginning of December. I did a test out of curiosity and here is what I found.

I was getting approximately 31.5 mpg on 87 and getting 33 on 93. When I averaged the cost of 87 per mile it was $0.1029 and 93 was $0.1084.
The difference being $.0055. So for the nominal fee per mile ($82.5 extra per 15k miles) I am burning a better fuel which will help my cars' motor stay "youthful".
Also, there is a product called Startron that I use. It is an enzyme that eats ethanol which beyond zapping mpg's can cause a plethora of other problems. I'd suggest using it too.


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## Vetterin (Mar 27, 2011)

31.5 mpg with an Eco? Even with an auto and city driving that sucks!


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## obermd (Mar 3, 2012)

As you can see from my fuel log below it took a few thousand miles for my ECO MT to start to shine. I agree that anything below upper 30s is low for an ECO. The ECO MT is rated 28 city and 33 combined, however. The ECO AT is about the same. Face it, the ECO trims don't really shine until you put them on the open road. Then the MT at least is nearly unbeatable.


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## Macman (May 4, 2011)

so far, my experience is:
93 oct: ~460 miles per tank
89 oct: ~370 miles per tank
87 oct: one tank was about 385, one was 422.
I'm trying one more tank of 89, then back to 93.


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## titan2782 (Nov 4, 2011)

91 (I can't get 93 here) because it's a boosted application and outside temps can get up to 120 here. Pointless to run anything below 91.


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## Poje (Aug 2, 2012)

I run 87 right now with stock Tune.

In the Spring/Summer i use 94 with my Tune and the difference between stock with 87 and tuned with 94 is insane, 1.2 sec on the Quarter mile doesnt seem much, but its enough to make me happy.


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## titan2782 (Nov 4, 2011)

1.2s is excellent for a $400 investment


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## cronyjabrony (Aug 10, 2012)

I must have a wacko motor in mine because anything less than 91 and she is running like garbage. Dead pedals and rough. I don't mind putting 91 in it because it gets 40+ MPG and its a small price to pay for an awesome happy motor.


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## DMC (Oct 22, 2012)

I run 89. Yes, the engine will run on 87, but it will aggressively retard timing at the first sign of knock. When you have a 9.5:1 compression ratio and then put boost on top of that, I feel better about higher octane. From reading through a few threads, people that have driving with a scanner see this quite a bit with 87 octane. While that's just the PCM protecting the engine, that's also not great for fuel economy or driveability. 

Edmunds essentially saw the same thing when they tested the Cruze:

2011 Chevrolet Cruze LTZ: The Ultimate Hot Weather MPG Test - Regular vs. Premium

While they didn't look at what was happening with the timing, they did see a significant difference in fuel economy with premium. Granted, this was in hot weather. In any case, the difference by me is only $.10/gal. Worth it to me to stick with 89 for this engine.


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## obermd (Mar 3, 2012)

cronyjabrony said:


> I must have a wacko motor in mine because anything less than 91 and she is running like garbage. Dead pedals and rough. I don't mind putting 91 in it because it gets 40+ MPG and its a small price to pay for an awesome happy motor.


This sounds like inconsistent spark plug gaps. Have you checked you plugs?


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## NickD (Dec 10, 2011)

No sense in arguing which octane is best for your Cruze, the EPA requires over a 155 different blends of gasoline that varies all over the country. You have to experiment which fuel is the best in terms of economy and performance.

It was within the last 8 or so years, the EPA required us guys living in the sticks to only be able to purchase so-called winter gas, with that stuff, fuel economy really suffers.

Also the Cruze has an anti-knock sensor, advances the spark advance to the point of pre-ignition, then backs it off a couple of degrees. When using the highest octane, from my experience, really pays in better overall performance and fuel economy. Then where I live, can only buy ethanol free gas with 91 octane.

Another problem with 155 blends of fuel, oil pipe mix ups, another reason for the high cost of fuels, and when you go to your regular gas station, you don't know what the heck you are getting. Still looking for EPA results on reduced emissions. But from I can find, just like R-12 refrigerant, just a theory, I like to see cold hard facts.

So exactly what is this tune up doing, really can't advance the spark anymore, only way to advance it to peak performance is to use the highest octane fuel available.

Liked it better when all parts of the USA used the same grades and type of fuels, really a mess.


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## speedy862004 (Dec 13, 2012)

Vetterin said:


> 31.5 mpg with an Eco? Even with an auto and city driving that sucks!



Yeah I drive in a lot of sitting traffic plus it was the holiday season when I first purchased the vehicle. Add in getting used to driving a stick again and bam... not as good mileage as should be. I live in Savannah ga so not sure if the climate makes any difference.
Anyway I'm getting 33.7 on the meter that keeps up with it. Was going to check the MPG the old school way, but forgot to get the gallons I filled up last time.


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## speedy862004 (Dec 13, 2012)

What is the Rostra cruise control for? Does it work better than the stock with MPG somehow or did you not have Cruise control in the car when you bought it?


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## obermd (Mar 3, 2012)

speedy862004 said:


> What is the Rostra cruise control for? Does it work better than the stock with MPG somehow or did you not have Cruise control in the car when you bought it?


Not all Cruzen come with a cruze control. If you have the OEM cruze control stick with it. Rostra is for those who don't have the OEM option.


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## obermd (Mar 3, 2012)

speedy862004 said:


> Yeah I drive in a lot of sitting traffic plus it was the holiday season when I first purchased the vehicle. Add in getting used to driving a stick again and bam... not as good mileage as should be. I live in Savannah ga so not sure if the climate makes any difference.
> Anyway I'm getting 33.7 on the meter that keeps up with it. Was going to check the MPG the old school way, but forgot to get the gallons I filled up last time.


Your car will also start improving. It took almost 10,000 miles for my ECO MT to really find it's fuel economy legs.


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## TODD2869 (Feb 18, 2012)

Its like the moron who drives 20 miles to save 3 cents per gallon. I often wonder if people really consider you might be saving 30-50 cents per tank for the extra time/miles.

Spent more to get there than they saved. 

I run premium. The car runs much better than regular and I spend an earth moving $2.00 extra on it.


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## rodneyiii (Oct 23, 2012)

shawn672 said:


> And for those who realize how bad 87 is for this engine, we also have Trifecta who data logged and saw actual KNOCK occuring with 87 and ambient temps were not even that high..





NickD said:


> Also the Cruze has an anti-knock sensor, advances the spark advance to the point of pre-ignition, then backs it off a couple of degrees.


Trifecta and any other logging method will ALWAYS detect knock because of what NickD mentioned in his statement. The ECM is constantly searching for the highest possible timing angle until the knock sensor tells it that it has gone too far. This is going on the entire time the engine is running (except maybe at idle). For the folks who bought the car for economy and drive it to achieve that, then 87 octane is within the adjustment limits of the ECM. For these people, higher octane won't do much since the engine is not being taxed where it needs a surplus of power. For the folks who bought the car to beat on it then 87 would be limiting the ultimate output of the engine because the timing is held back. So we have two camps and reasons for each fuel grade.

No one has mentioned that the owner's manual also recommends TOP TIER gasoline over unbranded gas due to the better levels of additives for keeping the fuel system, valves, and pistons clean of deposits that can accumulate to create detonation and poor fuel atomization. According to toptiergas.com, Shell is Top Tier but BP hasn't been certified yet. You may want to visit the website to see what fuel brands are top tier in your areas. There definitely is such a thing as cheap gas.


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## titan2782 (Nov 4, 2011)

rodneyiii said:


> Trifecta and any other logging method will ALWAYS detect knock because of what NickD mentioned in his statement. The ECM is constantly searching for the highest possible timing angle until the knock sensor tells it that it has gone too far. This is going on the entire time the engine is running (except maybe at idle). For the folks who bought the car for economy and drive it to achieve that, then 87 octane is within the adjustment limits of the ECM. For these people, higher octane won't do much since the engine is not being taxed where it needs a surplus of power. For the folks who bought the car to beat on it then 87 would be limiting the ultimate output of the engine because the timing is held back. So we have two camps and reasons for each fuel grade.
> 
> No one has mentioned that the owner's manual also recommends TOP TIER gasoline over unbranded gas due to the better levels of additives for keeping the fuel system, valves, and pistons clean of deposits that can accumulate to create detonation and poor fuel atomization. According to toptiergas.com, Shell is Top Tier but BP hasn't been certified yet. You may want to visit the website to see what fuel brands are top tier in your areas. There definitely is such a thing as cheap gas.


91/93 has already been PROVEN by many members as well as car magazines to provide increased MPG's, tuned or not.

And yes, we've mentioned it many times that top tier fuels should be used. Plenty of threads on both subjects.


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## 2013Cruze (Aug 4, 2012)

Mid grade 89 octane in winter.


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## speedy862004 (Dec 13, 2012)

Thanks for the feedback. It's awesome knowing its only gonna get better!


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## spacedout (Dec 7, 2010)

rodneyiii said:


> The ECM is constantly searching for the highest possible timing angle until the knock sensor tells it that it has gone too far. This is going on the entire time the engine is running (except maybe at idle). For the folks who bought the car for economy and drive it to achieve that, then 87 octane is within the adjustment limits of the ECM. For these people, higher octane won't do much since the engine is not being taxed where it needs a surplus of power. For the folks who bought the car to beat on it then 87 would be limiting the ultimate output of the engine because the timing is held back. So we have two camps and reasons for each fuel grade.



I bought the car for economy & am usually very easy on it, but with 87 octane I can fell surging on hills & hear knock followed by a loss of power on a few occasions. 91 octane is much better but from what I have seen 93 octane is when this motor really start to run great. 

The hills around where I live(200-400ft with 6-9% grades) I got knock & some pulsing even on 91 octane pure gas. With 93 octane with 10% ethanol I get none(so far). If I lived in a flat area like the state of Illinois I might be able to get away with 87 or 89 octane, but with the mix of flat & very steep grades around here I will be sticking with 93 octane only.


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## titan2782 (Nov 4, 2011)

spacedout said:


> The hills around where I live(200-400ft with 6-9% grades) I got knock & some pulsing even on 91 octane pure gas. With 93 octane with 10% ethanol I get none(so far). If I lived in a flat area like the state of Illinois I might be able to get away with 87 or 89 octane, but with the mix of flat & very steep grades around here I will be sticking with 93 octane only.


If you lived in Texas or Kansas where it's all flat then I'd say 87 is fine (if you're easy on it) but not if you have hills.


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## Macman (May 4, 2011)

I switched back to 93 octane and this looks like my best tank so far, may even go 500 miles! Though I wouldn't drive it until its empty, but I'll be able to wait pretty close to the end.


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## Pete in PA (Dec 1, 2012)

So far 89 for me. Only had the car in the winter, I'll see how it runs when it gets hot and go from there.

Around here 87 is $3.55, 89 is $3.65, and 93 is $3.83 so it can be a good $6 difference in a fill up. That can add up.


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## titan2782 (Nov 4, 2011)

Pete in PA said:


> $6 difference in a fill up. That can add up.


1) Not when you're seeing 5-10 mpg gain.
2) It's only $2.8 per 10/gal, not $6 (only $0.28 diff between $3.55 and $3.83 x 10 gallons). You waste more than that per day going to lunch/starbucks


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## Dennis_Mn (Jan 20, 2012)

First time I noticed this thread, but I have always just put in the cheapest that it will run on. However, I may try a few tanks of non-ethanol which is generally what the premium grade is in Minnesota. That may account for the mileage difference. I don't see any significance with the turbo in this discussion since it is down stream from the combustion process.


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## obermd (Mar 3, 2012)

Dennis_Mn said:


> First time I noticed this thread, but I have always just put in the cheapest that it will run on. However, I may try a few tanks of non-ethanol which is generally what the premium grade is in Minnesota. That may account for the mileage difference. I don't see any significance with the turbo in this discussion since it is down stream from the combustion process.


Higher octane is more resistant to knock. Turbos increase the pressure in the combustion chambers, which tends to increase knock. Running higher octane will therefore allow the car's ECU to not have to pull timing as much to avoid knocking.


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## jdubb11 (Mar 14, 2012)

Dennis_Mn said:


> First time I noticed this thread, but I have always just put in the cheapest that it will run on. However, I may try a few tanks of non-ethanol which is generally what the premium grade is in Minnesota. That may account for the mileage difference. I don't see any significance with the turbo in this discussion since it is down stream from the combustion process.


i live in the northern burbs of mpls. i had a ton of knock with 87 octane in the hot weather (90-95+). i switched to 89 and it is much much better. havent tried 91 and probably wont untill the real hot summer days next year to see if its any better then 89.


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## spaycace (Feb 9, 2012)

Vetterin said:


> I sure didn't buy a fuel miser to put premium in it!


I like people that think this way ... without doing any actual math calculations on their mpg in real-world testing. I thought that way when I first purchased the Eco, but then I actually TRIED 91 octane vs. 85 octane (that's what's lowest in Colorado) and noticed approximately 4-5 mpg increase! So, with simple math using those numbers, you'll find that a 4 mpg increase on 91 that costs 20 cents/gallon more will actuall SAVE you money! Let's just use some numbers shall we ... 85 octane @ $2.73/gal VS. 91 Octane @ $2.93/gallon and assume a paltry 35 mpg avg w/85 would get you 385 miles on 11 gals at a cost of $30.13; whereas 39 mpg avg w/91 octane would get you 429 miles at a cost of $32.33. Therefore, you have gone (theoretically of course) 44 miles further at a cost of $2.20 which is less than the cost of a gallon of 85 octane fuel AND you've gone further than that 1 gallon would have taken you anyway at a cheaper cost! Make Sense?


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## spacedout (Dec 7, 2010)

Dennis_Mn said:


> I don't see any significance with the turbo in this discussion since it is down stream from the combustion process.



Depends on which side of the snail your looking at, the exhaust gasses are spinning one side(post combustion), but the whole point/purpose of that process is to spin the shaft to the intake side to force feed in more air/pressure. 

Think of the exhaust side of the turbo like a water wheel at an old mill & the exhaust gasses as the water, its just the power source(spinning the shaft) for what is actually going on the other side.


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## obermd (Mar 3, 2012)

Spaycace - will your Cruze even run on 85 octane? Neither of mine will. This is the first car that I flat out cannot run 85 octane in Denver. My son discovered that even the LS runs better on 91 octane.


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## OnlyTaurus (Mar 20, 2012)

I created a thread when I found this out. I advise everyone to look at their RPO codes and look for, I think it's, KRD. If its there, its a code for '91 octane recommended'.

Sure the Cruze will run on 87, but the Cruzes sure do come to life on 91/93.

Sent from my DROID BIONIC using AutoGuide.Com Free App


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## Matt585 (Dec 19, 2012)

Ya I
Definitely put in 93 I mean on the price of it you pay what a few dollars more on a fill up? Worth it in my book. I put 93 in everything I've ever owned. Kwik fill usually 


Sent from my iPhone using AutoGuide.com Free App


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## RyanPatty (Sep 28, 2012)

I have ran 87 the whole time have 20,000 on it I'm the first 6.5 months of owning it and didn't think of it only being a extra dollar or 2 per fill up so next tank I'm going to start using 91 octane


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## Matt585 (Dec 19, 2012)

RyanPatty said:


> I have ran 87 the whole time have 20,000 on it I'm the first 6.5 months of owning it and didn't think of it only being a extra dollar or 2 per fill up so next tank I'm going to start using 91 octane


ya man youll see a great improvement its worth it. Let me know what you see difference wise. Maybe you could log what you have now (MPG etc.) and see how they compare id be interested in seeing that if it changes anything or whatnot besides being a lot better for your vehicle.


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## spaycace (Feb 9, 2012)

obermd said:


> Spaycace - will your Cruze even run on 85 octane? Neither of mine will. This is the first car that I flat out cannot run 85 octane in Denver. My son discovered that even the LS runs better on 91 octane.


Yes sir, my cruze does run on 85 octane ... but then again, I've had the Injen intake on it since it was a baby, or should I say at about 200 miles on the odometer. Actually ordered the intake by phone while sitting in the dealership waiting to drive away in the Eco from up in your neck of the woods! (Elway Chevrolet in Englewood) I also use a fuel additive every fill up that seems to help bolster the 85 octane better than it does the 91, even though it's not an octane booster. I have also re-gapped my plugs to .035 & that seemed to help out as well. Runs like a champ when I go back to 2000' altitude to see family and friends!


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## Macman (May 4, 2011)

So my first tank back on 93 got about 450 miles, which is about the highest ever. Today I filled up at Shell 93 octane, we'll see how it goes.


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## RyanPatty (Sep 28, 2012)

Just filled my car for the first time with 91 octane at 21000, what a difference.


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## Ru5ty (Jun 20, 2012)

89 octane here in canada costs 1.31 the litre. thats what i use... almost no knock , very rare since i switched.


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## rpcraft (Jan 12, 2013)

Ok, I know this is a little late to the party but simply running a higher octane fuel will not boost your power output? It's actually used to control detonation (or knock if you prefer) from increased heat, which is a by product of increased power (i.e. an elevated boost or tune that will produce more power = heat). I don't want to get into the science of it here but if you care to read here is some fine information provided by the wonderful state of Minnesota: 

http://mn.gov/commerce/weights-and-measures/images/OctaneFacts.pdf


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## obermd (Mar 3, 2012)

rpcraft said:


> Ok, I know this is a little late to the party but simply running a higher octane fuel will not boost your power output? It's actually used to control detonation (or knock if you prefer) from increased heat, which is a by product of increased power (i.e. an elevated boost or tune that will produce more power = heat). I don't want to get into the science of it here but if you care to read here is some fine information provided by the wonderful state of Minnesota:
> 
> http://mn.gov/commerce/weights-and-measures/images/OctaneFacts.pdf


This has been discussed nearly to death here. Higher octane is more resistant to knock. The two main contributors to knock are combustion pressure and temperature. Both the 1.8 and 1.4Turbo engines in the North American Cruze run at high temperature for efficiency. The 1.4T adds higher compression as well to further increase efficiency and is part of the reason the LT, ECO, and LTZ all enjoy better fuel economy than the LS. In addition, for efficiency the Cruze's ECU uses very aggressive ignition timing. To reduce the impact of knock, the ECU backs off the ignition timing, but at the expense of engine power and efficiency. By running higher octane the ECU doesn't have to back off ignition timing as much, resulting in improved engine performance, power, and efficiency. 

In the real world (as opposed to the EPA testing facilities), the 1.4T engine benefits to the tune of 3-5 MPG by increasing octane from 87 to 91. The 1.8 engine also benefits, but to a lesser extent. Both engines provide more low end power with higher octane. The easiest way to determine if you need to run a higher octane is by paying attention to the throttle feedback. If it's pulsing, increase your octane. The pulse is the result of the ECU pulling timing to avoid knock.


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## jdubb11 (Mar 14, 2012)

^^x2^^ i felt the pulsing in temps over 85 with the air conditioning on. ive been using 89 octane ever since and the pulsing has greatly been reduced/ is gone. havent, and probably wont try 91.


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## NickD (Dec 10, 2011)

Title of this thread is:

"Which octane do you use in your 1.4 (T?) Cruze?

Pump says Top Tier 91 Octane Ethanol Free!

What's coming out of that nozzle, I don't have the slightest idea. 

What I do know, whatever it is, getting 8 mpg less than what the calendar says the date is. January, I believe. Can't be the temperature difference, due to wind patterns, we have days in January that are actually warmer than days we had last June.

But apparently the EPA says its winter, therefore its cold, so therefore, have to use winter gas.

It did take them time to realize that when its cold, it does take a little more time to heat up the exhaust system components. A conventional O2 sensor is worthless until it warms up to about 350*F, thus came the open loop mode when the engine is first started. To accelerate the warm up time added a five cent nichrome heater to it. But where a typical 02 sensor retailed for around 30 bucks, the price skyrocketed to around 65 bucks.

Same is true with the catalytic converter, worthless when cold, they wanted an electric heater added to that. But an engine is only 15% efficient and the alternator is only 50% efficient for an overall efficiency of 7.5%! To gain closer to 100% efficiency, we suggest adding ignition to the cat and spray gas directly into it. DOT would never hear of that, could result in an explosion due to fail ignition, so that project was dropped.

Can you even imagine what an overpriced catalytic converter hanging under the vehicle exposed to road salt and other road hazards would cost the consumer?

So instead, the EPA started playing with the gas, but not based on actual temperature, based on the calendar. So thus the rotten fuel economy we are getting, based on the calendar.

Could waste your time and write to your congressman, I have better luck explaining this to my one year old grandson.


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## obermd (Mar 3, 2012)

jdubb11 said:


> ^^x2^^ i felt the pulsing in temps over 85 with the air conditioning on. ive been using 89 octane ever since and the pulsing has greatly been reduced/ is gone. havent, and probably wont try 91.


If you're happy with 89, there is no reason to pay the additional cost of 91.


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## mikep88 (Nov 12, 2012)

I voted 87, but I have tried both 89, and 91/93 for a couple of tanks. Can't say I've noticed any difference in fuel mileage, performace or smoother running engine with any of them, but it is winter here in northern NY so maybe it will be different come summer. And at $6.00 more a fill up here, I think I'll stick with the 87.


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## obermd (Mar 3, 2012)

mikep88 said:


> I voted 87, but I have tried both 89, and 91/93 for a couple of tanks. Can't say I've noticed any difference in fuel mileage, performace or smoother running engine with any of them, but it is winter here in northern NY so maybe it will be different come summer. And at $6.00 more a fill up here, I think I'll stick with the 87.


Good call. With the lower winter temps the intercooler isn't heat soaked, resulting in a slightly cooler compressed air flow from the turbo. When the temps start rising above 75-80F you may want to revisit your octane rating.


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## n4435rc (Apr 25, 2012)

Quick10 said:


> Where did they say you should run 89? I never got notified about that.


I too have not seen anything about 89 octane. I have tried all of them, mostly from Shell. 91 gave me the worst mileage and I could not detect any power increase at all. I have been putting in the lowest cost, mostly 89 with 10%ethenal. Most stations here have reg 87 without ethenal and 89 with 10%ethenal. I have kept track of all but the last few weeks of fillups. The tanks without ethenal are just very slightly better mileage, but not worth the extra cost. My engine always runs strong and smooth no matter what gas I have put in it. I think the compter adjusts to what you put in it. One note on power: during the very hot days in summer, 95F and up, the power is somewhat less, especially with heat soak sitting in hot sun.


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## 20131pz69 (Oct 22, 2012)

I run 91 octane. On my 2nd tank of 91, there was significantly less knock under regular driving and I can now shift up earlier without knock. Bottom line- I have increased mileage from the 91, the engine is safer due to less knock and will remain cleaner due to the increased amounts of detergent in the premium fuel. It may not be required, but it's financially sound ...

Before evaluating a change in octane, I would run through 2 full tanks of 91 or reset the ECU (disconnect battery for 30? minutes) so the cruze can re- calibrate.


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## Blue Angel (Feb 18, 2011)

obermd said:


> Your car will also start improving. It took almost 10,000 miles for my ECO MT to really find it's fuel economy legs.


Wow, really? I'm not there yet, only around 7k miles (11k kms) in the dead of winter and I'm completely impressed by my car's fuel-miserness. Any more will just be icing on top of the icing on the cake.


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## Blue Angel (Feb 18, 2011)

titan2782 said:


> 1)Not when you're seeing 5-10 mpg gain.


Care to share with the rest of us who is seeing 10 MPG gains? Going from 35 to 45 MPG is a 29% improvement, not likely on a fuel octane upgrade!

The most extreme example I've seen mentioned is 5 MPG. Let's try to keep this reasonably factual...


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## Blue Angel (Feb 18, 2011)

I've run several tanks of 91 in a row now. Because of the climate change since I bought the car in June (It was -24C/-11F this morning) the car "seems" to run better on 91, and the mileage "seems" as good as before considering the weather.

I will probably stay on 91 until the weather warms up and then do several double tank back-to-back switchups before coming to a conclusion. That is the only way to really quantify the change, and as has been discussed before, everyone drives in a different way in a different environment so a "one-size-fits-all" blanket statement about fuel octane is not likely to work here.

I think your driving style and transmission choice will play a LARGE part in this debate; engine load (how heavy your foot is) and engine RPM (transmission choice and driving style) are likely to be the two heavy hitters when it comes to octane requirement. Personally, I have an Eco MT and I keep the revs as low as possible at all times, going through slow corners idling in 3rd gear and pulling away slowly from 1100 RPM, cruising to work at ~1400 RPM @ 45 MPH. I have noticed a reasonable drivability improvement below ~1700 RPM using 91 (which seems to be where the turbo starts kicking in) and since that's where I spend litterally 99% of the time while driving I stand to notice an improvement much more than the driver of an automatic that hardly ever goes below 1500 RPM.

Different strokes for different folks...


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## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> I've run several tanks of 91 in a row now. Because of the climate change since I bought the car in June (It was -24C/-11F this morning) the car "seems" to run better on 91, and the mileage "seems" as good as before considering the weather.
> 
> I will probably stay on 91 until the weather warms up and then do several double tank back-to-back switchups before coming to a conclusion. That is the only way to really quantify the change, and as has been discussed before, everyone drives in a different way in a different environment so a "one-size-fits-all" blanket statement about fuel octane is not likely to work here.
> 
> ...


Generally speaking, cars are more likely to knock at low RPMs and high loads than they will at higher RPMs and lower loads. Running higher loads at low RPMs in your Eco MT (like mine) will reveal a significant improvement in low RPM power and smoothness. 

During normal weather that didn't require significant warm-up times or heavy A/C use, I would consistently average 39-44mpg with a 30-35mph average speed (65-75% city driving). This was done with 93 octane. I tried going down to 89 octane once and did not like it at all.


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## Aus348 (Sep 22, 2013)

I use 87 octane usually, and am in a very cold climate in the winter (-40°C) at some points and up to 40°C in the summer, what octane should I use and will i notice a difference in power?


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## Blue Angel (Feb 18, 2011)

Step 1: Try a tank of Shell 91 V-Power (run your previous tank down low to keep from diluting the new fuel too much). It's Ethanol free so it should have slightly higher energy content than other gasolines that have up to 10% Ethanol content. Any 91 will work, though, and you should notice better drivability especially in hotter weather with AC use.

Step 2: Check your plug gaps. On OE plugs and an otherwise stock stock (read - not tuned), you should use .030"-.035" gaps. Again, better drivability as well as smoother idle, and better torque off idle.

http://www.cruzetalk.com/forum/57-how-library/6722-diy-re-gap-factory-spark-plugs.html

Step 3: Upgrade your plugs. NGK BK7RE have widespread use here and work well, but won't last as long as the OE plugs. I've just started using NGK BKR8EIX plugs that should last like the OE plugs, but only myself and one or two other members have tried these out so they are not proven yet. BIG improvements in off idle torque, idle smoothness, low RPM torque (below 1200 RPM). If you drive a manual transmission this is something to look into:

http://www.cruzetalk.com/forum/34-1-4l-turbo/21850-hesitation-gone.html

Careful... following the above advice may turn you into a tweaker.


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## GM Master Tech (Nov 11, 2012)

As far as power most likely up about 10 hp running on 93 octane vers 87.And TQ will be up to by about the same amount.These motors like octane.And with a tune added on top. It really wakes things up.


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## rcclockman (Jan 16, 2012)

Has anybody ran 100 Octane just for the **** of it??


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## marden64 (Dec 1, 2013)

In my 35 years of driving, I've always ran Reg. in my car and haven't had any problems at all except for one car, my '94 Corsica. Within 5K km, I had to switch from Reg. to Pre. gas because of the additive that's added to the Canadian gas that's not in the US gas. It had the 2.2L in it that was made for the US market. I ended up having to replace the spark plug every time I had an oil change. Cost me $90 per time.


“The vast majority of our vehicles do not require premium fuel. There are a few vehicles we recommend premium for (but not required) and then a couple of high performance vehicles that do require it,” said George Saratlic, product communications manager with GM of Canada.

“All the information the customer needs regarding octane is in the owner’s manual. Each engine is designed for a specific octane requirement based on the performance of the engine. In all cases, GM recommends the use of top tier detergent gasoline.

“In Canada, Shell, Petro Canada, Esso and Chevron are all top tier suppliers. Top tier provides the GM recommended level of deposit control additives in all octane blends, while other gasoline brands may not,” he said.


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## Blue Angel (Feb 18, 2011)

marden64 said:


> In my 35 years of driving, I've always ran Reg. in my car and haven't had any problems...


Before buying my Cruze I was in the same mindset (other than my Corvette). The Cruze is the first turbocharged vehicle I've ever owned, and with the pressure OEMs are under to supply efficient, clean and powerful vehicles these days they are tuning very agressively. I also can't help but mention that the Indolene fuel the EPA uses for testing economy and emissions (and the fuel the OEMs are certifying with) is over 91 octane... draw your own conclusions.

In the Cruze turbo, it seems there are drivability gains to be had by using premium fuel. Some people are even seeing a small mileage increase, but this is dependant on driving style and environment... it seems people who live in very hot climates and use AC a lot benefit the most regarding mileage increases.



Blue Angel said:


> I will probably stay on 91 until the weather warms up and then do several double tank back-to-back switchups before coming to a conclusion. That is the only way to really quantify the change...


To follow up on what I said earlier in this thread (January 2013), I did do several back to back fuel changes between 87 and 91 (both Petro Canada E10 fuels) and found no observable or repeatable mileage trend that followed the octane rating. I even went to Shell 91 V-Power, a fuel advertised as Ethanol Free (E0), and couldn't produce any kind of confidence inspiring data trend suggesting a mileage improvement. All of my testing was based on steady speed cruising over a set course with the cruise control set, two way averages. In no way could I do acceleration or other high load testing with any repeatability, so in no way is my testing absolutely conclusive. As with everything, YMMV.

Here's an interesting read on fuels relating to the auto industry and modern engine calibration, for anyone interested:

Premium Gasoline – What Does Premium Fuel Do for Your Car? - Road & Track


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## Diesel Dan (May 18, 2013)

sciphi said:


> GM and a few auto magazines did prove the 1.4 does get better fuel economy in summer weather on premium.* It was about 3 mpg IIRC.* It was a large enough difference where it made up for the $2/tank extra for premium.


Not the case for our car. There was no discernible difference when switching from 87 from Sams club Vs Premium @ BP. 
If we are doing a long road trip in the summer I try and fill with premium and have done that even with none turbo cars.


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## jblackburn (Apr 14, 2012)

Blue Angel said:


> Before buying my Cruze I was in the same mindset (other than my Corvette). The Cruze is the first turbocharged vehicle I've ever owned, and with the pressure OEMs are under to supply efficient, clean and powerful vehicles these days they are tuning very agressively. I also can't help but mention that the Indolene fuel the EPA uses for testing economy and emissions (and the fuel the OEMs are certifying with) is over 91 octane... draw your own conclusions.
> 
> In the Cruze turbo, it seems there are drivability gains to be had by using premium fuel. Some people are even seeing a small mileage increase, but this is dependant on driving style and environment... it seems people who live in very hot climates and use AC a lot benefit the most regarding mileage increases.
> 
> ...


So what did you decide to run on a daily basis?

I have no problem matching MPG numbers in winter on 87 octane, and the drivability really doesn't change much either.

But any time it goes above mid-50s outside, I need to switch up a grade as all of my sub-2000 RPM pull goes away.

In the hot summer where temps are often in the 80s-90s, even 89 isn't enough. These high-strung little engines rely on boost so much that they're very prone to pre-detonation when hot.


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## obermd (Mar 3, 2012)

The Cruze is the first car I've owned that cannot be driven on the commonly found 85 regular octane in the Denver area. It definitely performs better on 91, at least at altitude. This is true for both my ECO MT and my son's LS MT.


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## Merc6 (Jun 8, 2013)

When I used 87 I had issues with miss fires and power was pulled to the point I couldn't drive 5th gear at speeds under 41 mph. 


Sent from my iFail 5s


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## pL2014 (Dec 29, 2013)

marden64 said:


> In my 35 years of driving, I've always ran Reg. in my car and haven't had any problems at all except for one car, my '94 Corsica. Within 5K km, I had to switch from Reg. to Pre. gas because of the additive that's added to the Canadian gas that's not in the US gas. It had the 2.2L in it that was made for the US market. I ended up having to replace the spark plug every time I had an oil change. Cost me $90 per time.


Hehe, I had a '94 Corsica as well. Mine had the 3.1 V6. That was a great car. I sold it to my mother in law with 105k and she drove it (didn't maintain it well and hit more than one deer) to over 200k.

I'm only on my 2nd tank (besides what the dealer gave me). I put 87 in the first time and only got 25 mpg. I'm on 89 this time and my DIC says 28 mpg so far (~120 miles). We'll see. It's been a little warmer here so far on this second tank, but it's getting cold again. I'm really hoping the economy improves as the engine breaks in (or with higher octane, or as the weather warms up in the spring or a combination of all three. 

I do miss my Olds Intrigue which sat at 2k rpm at about 76 mph. I could get 30 mpg on the highway almost regardless of speed. Almost the same mpg at 65 as 85. That car loved the freeway. City driving was another story entirely.


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## Nobody (Feb 12, 2012)

Premium Gas from Shell stations only. 93 octane


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## Blue Angel (Feb 18, 2011)

jblackburn said:


> So what did you decide to run on a daily basis?


I've been running Shell 91 V-Power E0. Even in the cold winter months running on 87 leaves a little on the table at the lowest RPMs, it just feels more consistent on 91. Also, I've been screwing around with different spark plugs since the fall and I want to make sure my observations of each plug are as accurate as possible. That means not changing fuels.

Remember... I'm lugging this little turbo booger Eco down to 26 MPH under load up inclines in 6th gear, that's less than 800 RPM! With the latest BKR8EIX plugs it's unreal how smooth it lugs along down there. Looking forward to warmer weather to test with AC use. I may try a tank of 87 with these plugs just to see how they cope in cold weather. Maybe they'll be better than the BKR8E-11 plugs I just took out?


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## jblackburn (Apr 14, 2012)

> Remember... I'm lugging this little turbo booger Eco down to 26 MPH under load up inclines in 6th gear, that's less than 800 RPM!


Aye, that is one caveat of the 87...the RPM band shifts up like 200 RPM. I cannot run at 1200-1300 and still be happy while pulling through a gear...and on poor-quality 87, it can be very jerky (omg, Costco's was terrible - I could floor it up a hill in a high gear and it would just trip over itself). So far, between this and the Toyota that's also picky about what it runs on...I've found a few stations that seem to agree with the cars.

Nonetheless, for the cost benefit of using that over 89/93, and getting the same [or slightly worse] mileage @ 60 cents less per gallon...I'll run it while I can during these cold months and just tweak my driving habits slightly. 

At least it's nothing like how I have to adjust to running the car with the AC on in the summer


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## 2011Sipper (Dec 5, 2013)

I tried 87-92 octane in my Eco Mt and find that it's how I drive that makes the difference. Right now I'm on 87 octane @ $2.89 a gallon getting 46mpg avg. Drive like a grandpa and save $$$$! 

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## obermd (Mar 3, 2012)

My ECO MT is happy at 1100 RPM on the new copper plugs and I'm testing 87 octane. On my next tank I'm going to give 85 a try. Remember, 85 is "regular" here.


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## jandree22 (Sep 19, 2011)

I've been running 92 since I got the car last month, but with the much colder ambient temps recently I decided to give 89 a try to save some money during winter. It was 'okay' for a day or two then I noticed pulling in 6th gear was really beginning to throw a fuss at 37-40 mph which is a bread-and-butter speed for my area. Plugs are gapped to 0.034".

Ran the 89 tank empty and refilled with 93 and the difference back to premium is utterly remarkable. Like night-and-day. I find myself successfully getting into 6th at 30mph if I'm gentle on the throttle, 35mph+ can accelerate smoothly. Higher into boost it regained a _ton _of zip and feels silky. First 4 miles of this current tank on level terrain I pegged 68.7 on the DIC (lol), and it's aiming to be my first true 40mpg fill! We'll see tomorrow afternoon. _(*Edit*: Ended up getting my first 40+ tank, 40.4!)_

What a great way to start the day, I <3 this car!


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## MattMD (Jan 17, 2014)

I almost always put in mid-grade. Not so much for mpgs(seems to have only a small effect), but for performance. Just feels peppier with higher octanes.


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## Blue Angel (Feb 18, 2011)

jandree22 said:


> ...then I noticed pulling in 6th gear was really beginning to throw a fuss at 37-40 mph which is a bread-and-butter speed for my area. Plugs are gapped to 0.034".
> 
> Ran the 89 tank empty and refilled with 93 and the difference back to premium is utterly remarkable. Like night-and-day. I find myself successfully getting into 6th at 30mph if I'm gentle on the throttle, 35mph+ can accelerate smoothly.


You, my friend, are an EXCELLENT candidate for a spark plug upgrade... a true "Eco Lugger". See my post above for links!

With gaps at .030"-.035" and 91 octane, NGK BKR7E = Smooth 28-29 MPH in 6th


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## ChevyAllDay (Jul 24, 2013)

91 octane all day.... aaaaand tomorrow


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## jandree22 (Sep 19, 2011)

Blue Angel said:


> You, my friend, are an EXCELLENT candidate for a spark plug upgrade... a true "Eco Lugger". See my post above for links!
> 
> With gaps at .030"-.035" and 91 octane, NGK BKR7E = Smooth 28-29 MPH in 6th


Cool, much appreciated! I clicked into jblackburn's Hesitation Gone thread and quickly realized I'll need to block off some serious time later to dive into it, lol


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## jandree22 (Sep 19, 2011)

Beating a dead horse, but I got curious and went to look into an owners manual for a foreign Cruze. Here's one from the UK. 1.4T (Engine Code LUJ) calls for RON Octane 95 Recommended, 91 Possible. AKI conversion for US/Canada converts into 91 Octane Recommended, 87 Possible.

Same engine, US Owners Manual just omitted the "91 Recommended".

UK Cruze Owners Manual - Page 290
http://www.chevrolet.co.uk/pdf/manuals/om_cruze_kta-8301_2-en_eu_my13_ed0812_21_en_gb_online.pdf


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## Blue Angel (Feb 18, 2011)

jandree22 said:


> Same engine, US Owners Manual just omitted the "91 Recommended".


Nice find!


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## obermd (Mar 3, 2012)

jandree22 said:


> Beating a dead horse, but I got curious and went to look into an owners manual for a foreign Cruze. Here's one from the UK. 1.4T (Engine Code LUJ) calls for RON Octane 95 Recommended, 91 Possible. AKI conversion for US/Canada converts into 91 Octane Recommended, 87 Possible.
> 
> Same engine, US Owners Manual just omitted the "91 Recommended".
> 
> ...


Now we have "proof" that Chevy dumbed down the US Owners manual. Thank you.

Also, from page 229 of the same manual:



> Use of fuel with too low an octane rating can reduce engine power and torque and slightly increases fuel consumption.


 This is exactly what we've been telling people here ever since I joined two years ago.


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## obermd (Mar 3, 2012)

I also noticed that that manual says to use only DOT 4 brake fluid vs. the DOT 3 in the US.


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## Bullet (Aug 9, 2013)

Remember that the octane rating is different there. Our manual also says 95 recommended, 91 possible. Still I'm a bit confused because Neste Oil sells (or at least did earlier) a lot of British fuel from here, but I remember there still were some difference in the octane, or was it in the quality in some other way. Can't be sure. But for that I'm sure the octane rating is different in USA than here. Before any comparation it would be good to check the rating and other quality factors too.

"Auton tiedot
Moottorin tiedot
Tyyppimerkintä 1.4 T 1.6 D 1.6 D 1.8 D 1.7 Dsl 2.0 Dsl
Moottorin tyyppimerkintä LUJ LXT LDE 2H0 LUD LNP
Sylinteriluku 4 4 4 4 4 4
Iskutilavuus [cm3] 1364 1598 1598 1796 1686 1998
Moottorin teho [kW] 103 80 91 104 96 120
käyntinopeudella 6000 6000 6200 6200 4000 3800
Vääntömomentti [Nm] 200 150 155 176 300 360
käyntinopeudella 1850-4900 4200 4000 3800 2000-2500 2000
Polttoainelaji Bensiini Bensiini Bensiini Bensiini Diesel Diesel
Oktaaniluku (RON)
suositeltu 95 91 95 95
mahdollinen 91 87 91 91"


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## obermd (Mar 3, 2012)

The octane rating in the US is the average of the RON and MON ratings. Europe only uses RON, which runs higher than MON. The conversion of 95 RON to 91 (US) is accurate. Also, one of our members discovered that his 1.4T Cruze has an engine RPO code calling for 91 octane (US). The 87 octane (US) is nothing more than a marketing concession because American drivers have been conditioned for so long that 87 is regular. With today's engines this is no longer true in many cases and the car manufacturers are playing games with the timing maps and knock retard algorithms to allow the new higher compression engines to run on 87 octane.


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## NickD (Dec 10, 2011)

Ha, like Greek, read this, besides only using top tier gasoline.

"Gasoline Specifications
(U.S. and Canada Only)
At a minimum, gasoline should meet
ASTM specification D 4814 in the
United States or CAN/CGSB‐3.5 or
3.511 in Canada. Some gasolines
contain an octane-enhancing
additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). We recommend
against the use of gasolines
containing MMT. See Fuel Additives
on page 9‑45 for additional
information."

Just make sure you check with that minimum wage person behind the counter that their fuel meets ASTM specification D 4814.

Can get further reading here:

ASTM International - Standards Worldwide

CO reduction is only required during open loop mode when the engine, O2 sensors, and catalytic converter is ice cold. But in say a 500 mile trip, this stuff is only good for the first couple of miles. As little as a 30*F change in ambient temperature gives reason for winter gas. That is nothing compared to the temperatures seen in the catalytic converter after it heats up. 

So instead of seeing 630 miles remaining in the summer,, last time was only 408 miles after a fill up. Can''t even make a round trip to Milwaukee anymore without filling up at $$$$ prices.

But if you read the above article, will know what idiot signed this into law. And unfortunately, replaced by another idiot. Not only rotten gas, but huge expenses in health insurance cost.


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## jblackburn (Apr 14, 2012)

NickD said:


> Ha, like Greek, read this, besides only using top tier gasoline.
> 
> "Gasoline Specifications
> (U.S. and Canada Only)
> ...


Don't think winter gas is to blame...cold is to blame. Winter gas = 2% reduction in mileage. Below 20F outside, my MPG drops like a brick, even in highway driving, using the same gas that was in my tank a week or two before that I was getting good mileage on. It's something about how the Cruze's ECU maps are set up.

But as always, blame the "idiots" for it if you want...


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## NickD (Dec 10, 2011)

jblackburn said:


> Don't think winter gas is to blame...cold is to blame. Winter gas = 2% reduction in mileage. Below 20F outside, my MPG drops like a brick, even in highway driving, using the same gas that was in my tank a week or two before that I was getting good mileage on. It's something about how the Cruze's ECU maps are set up.
> 
> But as always, blame the "idiots" for it if you want...


Not just the Cruze with this cold weather problem, anyone I have spoke to with any vehicle has this same exact problem.

This includes pre-OBD I, vehicles, OBD-1, vehicles, and OBD II. Fuel economy in the winter declines anywhere from 17-27% with at least a 22% average. Doing nothing to the vehicle except fill it up with summer gas, mileage goes back up to where it should be.


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## jblackburn (Apr 14, 2012)

NickD said:


> Not just the Cruze with this cold weather problem, anyone I have spoke to with any vehicle has this same exact problem.
> 
> This includes pre-OBD I, vehicles, OBD-1, vehicles, and OBD II. Fuel economy in the winter declines anywhere from 17-27% with at least a 22% average. Doing nothing to the vehicle except fill it up with summer gas, mileage goes back up to where it should be.


Yep, sounds like the cold, not the gas. I was able to average 40+ MPG all last weekend, even with heavy traffic...and it had nothing to do with the gas and everything to do with warmer temperatures for once.

There are many, many factors at play when temps drop that causes MPG drop, including time it takes the motor to warm up (running pig rich while it does), increased alternator load, richer fuel-air mixture due to denser air, more aerodynamic drag due to denser air, thicker fluids creating tons of drag, increased rolling resistance from tires, etc. Claiming that a 17-27% change is solely to blame on the gasoline you put in the tank is an absolutely ridiculous blanket statement.


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## Blue Angel (Feb 18, 2011)

Bingo


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## NickD (Dec 10, 2011)

Certainly can't speak with any degree of authority on this subject. My old 1965 Buick Electra would always give me 20 mpg in the summer or the winter. Gasoline back then was 120,000 BTU per gallon. Today can vary anywhere between 92,000 to 114,000 BTU per gallon.

Read one place, 55 different blends of gasoline, another 155 different blends of gasoline. Read about adding ethanol, butane, oxygenating gas, MTBE's, nitrogen, reformulation. Blaming denser air, lower tire pressure, thicker engine oil, increased wind resistance, snow packed on the vehicle, Ambient temperature, and other variables.

Should be a substantial difference in temperature when its 30 above or 30 below. Is not with winter gas, still averaging around 30 mpg depending on the date on the calendar that by experience, is the key factor in fuel consumption.

Know for a fact the fuel economy really drops when my Cruze is plowing snow, but don't judge this. Use long trips on a cleared interstates for comparison driving at the same speed or even slower in winter months. 

Also read why do gas prices go down in the winter? Maybe in some areas, but not here, only time it really goes down is during a presidential election, and after this is over, right back up again, as high as $4.60 per gallon. 

1984 Honda DX with a MT was a good example of good fuel economy, always 46 mpg on long trips, regardless of the season. Something changed since then. Maybe I should be thankful in that I am still getting 30 mpg.

Maybe I should learn how to determine the BTU value of gasoline, even if I did, couldn't do a darn thing about it.


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## obermd (Mar 3, 2012)

My ECO MT has been running around 40 MPG for the past few weeks. This morning the 25 mile average pegged 50 MPG and the 50 mile average got up to 49.8 MPG. On this same tank of gas earlier in the week I was lucky to get 40. Given that I haven't filled up since last Friday this tells me that very cold temps really kill the fuel efficiency of the Cruze.


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## NickD (Dec 10, 2011)

Ha, one way I would know for sure would be to fill my 120 gallon tank in my motorhome this summer, and pump this into my Cruze next winter. Should be able to fill the tank in the Cruze at least 9 times.


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## Clausses (Sep 8, 2014)

Do you guys think 100 octane race gas would hurt the car if I were to run some? There's a gas station around me that I just found out has some. I just don't want to hurt the little 1.4t


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## hificruzer226 (Mar 27, 2013)

Clausses said:


> Do you guys think 100 octane race gas would hurt the car if I were to run some? There's a gas station around me that I just found out has some. I just don't want to hurt the little 1.4t


You wouldnt be able to pump it directly in to the car


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## Clausses (Sep 8, 2014)

Do you think there would be any safe gains from using 100 octane, though?


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## jblackburn (Apr 14, 2012)

Clausses said:


> Do you think there would be any safe gains from using 100 octane, though?


On a stock tune? Nope. On a very heavily modified "race" tune? Maybe.


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## Clausses (Sep 8, 2014)

I'm tuned. Would it be safe to run the 100 octane?


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## Bones (Jun 30, 2015)

I top up my tank with 87 mostly, but usually aim (begrudgingly) for an 89 or 91 (putting 93 in this engine makes me cry), and when It starts sputtering, I throw in an octane booster. Stops the sputter, doesn't help a **** thing else. Still can't get up above 33 MPG.


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## Clausses (Sep 8, 2014)

Bones said:


> I top up my tank with 87 mostly, but usually aim (begrudgingly) for an 89 or 91 (putting 93 in this engine makes me cry), and when It starts sputtering, I throw in an octane booster. Stops the sputter, doesn't help a **** thing else. Still can't get up above 33 MPG.


Do you have the M/T or the A/T?


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## Bones (Jun 30, 2015)

Auto. And it doesn't like the summer weather down here.


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## IndyDiesel (May 24, 2015)

Just completed a 1600 mile road trip, it was upper 80s and I got 43.74 mpg, I wasn't really driving for max mpg. I used little less than 37 gallons of gas. I tried premium gas for first time and I did notice some difference in driving, not sure I saw much of an increase in mileage but only used 12 gallons of premium and 25 of regular 87. My car drives and performs well on 87. I plan to continue to use 87 octane.

I have a 14 eco 6 speed manual and it has15k miles.


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## Clausses (Sep 8, 2014)

Indyeco6spd said:


> Just completed a 1600 mile road trip, it was upper 80s and I got 43.74 mpg, I wasn't really driving for max mpg. I used little less than 37 gallons of gas. I tried premium gas for first time and I did notice some difference in driving, not sure I saw much of an increase in mileage but only used 12 gallons of premium and 25 of regular 87. My car drives and performs well on 87. I plan to continue to use 87 octane.
> 
> I have a 14 eco 6 speed manual and it has15k miles.


Have you re-gapped your spark plugs so that they're all the same? And, I'm tuned so I really can't run anything below 91. I just want to make sure 100 hurt the engine.


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## Beelzebubba (Apr 3, 2015)

Clausses said:


> I'm tuned. Would it be safe to run the 100 octane?


Like E85? (100 to 105 octane)

I strongly considered the E85 tune on my old PT Cruiser GT. SRT/4s did well on it.

I honestly haven't researched 1.4t E85 tunes.

Ran E85 in my Flex Fuel Pentastar...Power, throttle response...everything was the same as 93 octane. Everything but fuel economy that is. Crashed down to an all time low of 14 mpg.


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## jblackburn (Apr 14, 2012)

Clausses said:


> I'm tuned. Would it be safe to run the 100 octane?


Is it E10 (I know Sunoco has one in some areas) or E85? You can't run E85 without changing injectors/getting a tune specificially for it.

But I really think you'd be throwing money away unless you get the car tuned to take advantage of 100 octane specifically. Most aftermarket tunes are set to hit their power/torque gaps on standard 91/93 octane. If you hit the torque limiter in the ECU, the car won't give you any more power.


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## Clausses (Sep 8, 2014)

It's not e85, it might be e0.


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## IndyDiesel (May 24, 2015)

Clausses said:


> Have you re-gapped your spark plugs so that they're all the same? And, I'm tuned so I really can't run anything below 91. I just want to make sure 100 hurt the engine.


My car runs well and only has 15k miles, I am not messing with any regap. If something isn't working well I will take to the dealer. I would never do a tune either.


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## Clausses (Sep 8, 2014)

It runs a lot better after a regap. My plugs had a .08 difference. That's enough to be harmful.


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## UlyssesSG (Apr 5, 2011)

FatKidsCruze said:


> Premium 93 from Shell or BP for me... I'll soon be Trifecta tuned and use 93 anyway.


*Ditto here.* In my Trifecta-tuned 2014 RS there is a huge difference in available power and performance with 93 octane when compared with mid-grade 89 octane. It's a night and day, _feel-it-in-the-seat-of-your-pants, put-a-Cheshire-Cat-grin-on-your-face _difference!

Heck, I wouldn't mind running though a tank of pure Sunoco Racing or 100LL AvGas to see if the tune can make the most of it. Anybody out there tried either of these fuels?


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## txcruze26 (Jul 7, 2015)

93/Exxon


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## Drew's Cruze (Jul 31, 2015)

I've only filled up twice in my new Cruze, so I can't make any conclusions yet. I assume the car came from the dealer with a full tank of 87, and I've filled up with 89 (although both times was less than a half tank) and most of my miles have been highway, which will not be the case for normal driving. The car runs fine. No stumbling or hesitation, and my mpg is 32+ for a couple interstate runs that were more Burt Reynolds than Ed Begley Jr.

The difference in price here is about $0.50/gal between regular and premium at a nearby Mobil (~$0.60 at Shell). Assuming a 3mpg difference (27 vs 30) between using reg vs premium (and of course, assuming regular gas is within warranty/engine longevity constraints), it would be more expensive to run premium gas. At a $0.50/gal cost difference, there would have to be about a 5mpg delta to justify the more expensive gas, considering current prices in this corrupt, overtaxed town.

Most of my driving will be piddling around in traffic, playing kid taxi, with the occasional road trip. Not too much highway commuting. So, any subjective value from "more lively throttle response," etc. from premium will be lost on me. My other vehicle is a Gen 1 Prerunner Tacoma auto - believe me, the Cruze is plenty "more lively" than that! That isn't to say, however, that I won't try out a few tanks of premium to see for myself what the difference will be.


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## obermd (Mar 3, 2012)

Drew, this is what every single person needs to do... try the different octanes to determine the best price/performance for their driving style and environment.


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## KOBALT (Nov 19, 2013)

Personally, i think the price difference isnt that big of a deal. Youll def get the performance from 93 for sure. I dont think skimping out on cheaper fuel is gonna benefit you. Its been proven that premium runs better in this vehicle.


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## GMFanatic (Jan 5, 2016)

From what I have noticed, if I'm coming out a corner in 3rd gear and really keep the engine at lower RPMs and squeeze the throttle I can absolutely tell a difference between premium fuel and regular. This to translates into the engine having to work less hard to move the weight, because it can take full advantage of the added boost at lower RPM. In this turbocharged car I'll swear by premium fuel. At $3.00 more per fill up it's worth the peace of mind.


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## spacedout (Dec 7, 2010)

GMFanatic said:


> From what I have noticed, if I'm coming out a corner in 3rd gear and really keep the engine at lower RPMs and squeeze the throttle I can absolutely tell a difference between premium fuel and regular. This to translates into the engine having to work less hard to move the weight, because it can take full advantage of the added boost at lower RPM. In this turbocharged car I'll swear by premium fuel. At $3.00 more per fill up it's worth the peace of mind.


Agree 100%, I find it hard to believe everyone doesn't notice the lack of power you describe, both my 2012 cruze and my 2015 sonic 1.4T behave the same way. Guess it boils down to how your driving the car if you can tell the difference. 

I also find with regular gas the engine seems to rev slower (especially in the upper RPM range), making more noise than power. This slow RPM climb means when accelerating you are spending 2X the time at high RPM than with premium gas. Use a stop watch and compare, I think you will be stocked how much more time the car spends reaching redline in each gear comparing 87 octane to 93 octane. On the dyno I'm not sure there would be a measurable difference comparing octane on a stock tune, I think what people are feeling is the much faster RPM climb making what power there is more readily available.


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## Andre2404 (Jan 9, 2017)

Ibe been running 87 for the first year, not a bad ride but at the beginning of 2017 i found that turbo engines run better with a higher octane because basically a bigger explosin in the engine. But so far on 93 everything improved, it doesnt hesitate when the gas pedal is pressed like on 87, runs smoother, acceleration improved, when i was on 87 i averaged 30.1 mpg (lot of city driving) with 93 im on a half of tank but ive already jumped to 34.1 running 93. Id say if its only gonna cost u a few bucks more for premium why not run it if it helps the car.


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## BMcCruze89 (Jan 6, 2017)

I've always put 87 as recommended by the owner's manual. However I never had a turbocharged engine, so never thought twice about getting a higher octane gas. It sort of makes sense as my other car that didn't have quite as high of a mpg (08' Mitsubishi Lancer) at times seem like one fuel tank matched what I saw in my new car (420-450 mi). I definitely agree with "to each their own". Given that we all have different driving habits, climates, typography, etc... 

Just my two cents


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## Sklyn (Jan 7, 2017)

Always use premium, but for us in oz thats 98 octane and you notice a big difference compared the the minimum 91 crap they sell. I won't put that in my lawn mower!
Having tested both in the cruze i found consumption around 10L/100km using 91 and about 8L/100km on 98. thats 2L every hundred k's.
The extra cost is about 23c per litre.
So, $1.40 x 10L = $14 for 100km on 91 and $1.63 x 8L = $13.04 for 100km on 98.
Its actually cheaper to run the premuim fuel as well as being better for the engine and your enjoyment! =)

Obviously there are a lot of factors which can change the results but its always going to be pretty close so I will always chose the better product.


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## Patman (May 7, 2011)

Now that it is cooler in Cincinnati, I started using 89 again and my car is doing OK as my last tank was 38.9 with it. When it is warmer, I will most likely switch back to 93 again. After I filled up I reset my trip ODO and got on the hwy and watched my MPG go up to @ 77 MPG until I hit some hills now it is in the 50s.


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## 2015LT2 (Jan 20, 2017)

I run *87* in my Cruze, it seems to run fine.:biggrin:


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## obermd (Mar 3, 2012)

2015LT2 said:


> I run *87* in my Cruze, it seems to run fine.:biggrin:


Chevy changed the low octane timing map for 2015. They also did some other tuning of the fuel ignition control system to help the car run better on 87 octane. As long as you're happy with how your car runs on 87 octane stick with it.


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## IndyDiesel (May 24, 2015)

I bought a 98 Camaro SS convertible new, it had a 350 and called for premium gas, always put premium in it and I did not drive it very much so it wasn't a big deal. Then and for many years there was about a 20 cent premium over regular gas. Here today in Indiana premium gas is about 60 cents more per gallon and at roughly 2 dollars for regular and 2.60 for premium that is a 30% difference, why is it a 30% today and roughly 10% difference several years ago?


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## a2chris (Jan 13, 2017)

IndyDiesel said:


> I bought a 98 Camaro SS convertible new, it had a 350 and called for premium gas, always put premium in it and I did not drive it very much so it wasn't a big deal. Then and for many years there was about a 20 cent premium over regular gas. Here today in Indiana premium gas is about 60 cents more per gallon and at roughly 2 dollars for regular and 2.60 for premium that is a 30% difference, why is it a 30% today and roughly 10% difference several years ago?



I noticed that same thing. The difference in grades used to always be .10 in the 90s and early 2000s. Then gas shot up but the grades stayed only .10 apart making them a lower percentage increase (like 2.00 2.10 and 2.20). My 4.3 Vortec v6 used to get 10% better gas mileage with premium that was 10% more expensive so it was a wash except I was able to fill up less often. Now that it is .60 more it is not really worth it except for piece of mind.

In my 2011 Cruze 1.4 I use Costco (top Tier FWIW) 93 like 90% of the time since I work nearby. That did not seem to stop me from getting a cracked piston at 42k miles. Detonation was supposedly the cause of cracked pistons in the 2011 models. I did run some tanks of 87 this winter when the difference was over .70 a gallon


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## obermd (Mar 3, 2012)

a2chris said:


> I noticed that same thing. The difference in grades used to always be .10 in the 90s and early 2000s. Then gas shot up but the grades stayed only .10 apart making them a lower percentage increase (like 2.00 2.10 and 2.20). My 4.3 Vortec v6 used to get 10% better gas mileage with premium that was 10% more expensive so it was a wash except I was able to fill up less often. Now that it is .60 more it is not really worth it except for piece of mind.
> 
> In my 2011 Cruze 1.4 I use Costco (top Tier FWIW) 93 like 90% of the time since I work nearby. That did not seem to stop me from getting a cracked piston at 42k miles. Detonation was supposedly the cause of cracked pistons in the 2011 models. I did run some tanks of 87 this winter when the difference was over .70 a gallon


The actual cause of the cracked pistons was using two incompatible metals in the cylinders.


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## jblackburn (Apr 14, 2012)

obermd said:


> The actual cause of the cracked pistons was using two incompatible metals in the cylinders.


There are a couple theories. Factory ring gap, detonation, or just bad piston design surrounding the rings are the top 3. Haven't heard of incompatible metals?

Given GM's troubles with the 2.0 and cracked pistons (engine tune) and melting pistons on the new 1.5 (also engine tuning), they do have a track record of it.


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## RatBoy (Jan 19, 2017)

Just picked up a 2017 hatchback on Friday.

I was surprised to hear my dealer tell me that 87 was fine; as well, the owner's manual says "Regular gasoline with an octane rating of 87 or higher". I was under the impression that supercharged and turbocharged engines always needed 91+. I've had three supercharged cars, but not a turbo.

I answered 87, but I reckon I'll experiment. I'm assuming my tank from the dealer is 87, and I see no issues right now. I didn't buy the car for its speed, just to have something to tool around in that would be easier to maneuver and park in the city, parking lots, and garages than my Suburban.

After about 120 miles, the Cruze is telling me its getting around 35 mpg. I'm happy!


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## jblackburn (Apr 14, 2012)

RatBoy said:


> Just picked up a 2017 hatchback on Friday.
> 
> I was surprised to hear my dealer tell me that 87 was fine; as well, the owner's manual says "Regular gasoline with an octane rating of 87 or higher". I was under the impression that supercharged and turbocharged engines always needed 91+. I've had three supercharged cars, but not a turbo.
> 
> ...


Direct injection helps reduce knock caused by preignition on lower octane gas. Mine definitely runs ok on 87, although I *think* it gets slightly better mileage on 89 or above. Although I have almost 3500 on mine now, my driving has been too mixed to really tell. I can't tell any difference in performance though - it was very noticeable with the old engines.


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## Merc6 (Jun 8, 2013)

jblackburn said:


> Direct injection helps reduce knock caused by preignition on lower octane gas. Mine definitely runs ok on 87, although I *think* it gets slightly better mileage on 89 or above. Although I have almost 3500 on mine now, my driving has been too mixed to really tell. I can't tell any difference in performance though - it was very noticeable with the old engines.


There is way more nanny tech on these new age turbo cars to help it run 87 but usually timing is pulled. I have to find the article again that said EPA and manufacturers use a standard fuel across the board not commercially available that pretty much is a higher than 87 octane for its EPA and HP ratings. It's hard to sell a economy car with a premium fuel requirement. that whole low cost of ownership goes out the window. My car just didn't like 87 and wasn't recalled for it.

Like my Accord for example holds a whole 7 ish more gallons than my eco manual and with 87 Vs the eco on 93 it gets about the same 380-400 miles for same price point.


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## BMcCruze89 (Jan 6, 2017)

For the record I hate using This forum on a mobile phone. This is my third time trying to comment without accidentally clicking out of the comment box to vote in the poll.

Anyways long story short, went from 87 to 93 today and was able to feel the difference instantaneously. My biggest issue with my car was the jerking it would do from one gear to the next (auto transmission). My dealer said it was adaptive transmission, but I knew it wasn't. Anyways I would recommend the 87ers like myself to go to a kid or high grade octane gas and see if you feel the difference. If you're worried about cost. Just do half a tank and see for yourself. Accept this challenge and let me know if you felt a difference in your engine shifting gears.


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## Merc6 (Jun 8, 2013)

BMcCruze89 said:


> For the record I hate using This forum on a mobile phone. This is my third time trying to comment without accidentally clicking out of the comment box to vote in the poll.
> 
> Anyways long story short, went from 87 to 93 today and was able to feel the difference instantaneously. My biggest issue with my car was the jerking it would do from one gear to the next (auto transmission). My dealer said it was adaptive transmission, but I knew it wasn't. Anyways I would recommend the 87ers like myself to go to a kid or high grade octane gas and see if you feel the difference. If you're worried about cost. Just do half a tank and see for yourself. Accept this challenge and let me know if you felt a difference in your engine shifting gears.


2015 LS? Some have said they also respond to 93 but the 1.4 actually has it's delay in changing to 91 map and holding it. 1st tank on a 87 used Cruze you get a small taste of 91 map after fuel up and you take off into traffic out the station. At some point, it eventually default back to 87 fuel map on that 1st tank of 91/93. Reason we say it takes a few consecutive fuel ups to fully have just 93 only in the tank. The knocks set off the nanny tech and it will flip back to 87 even if you been running 93 this whole time.


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## BMcCruze89 (Jan 6, 2017)

I'm sorry that was too advanced for me lol. I have the 2016 LT. I was going to say when I first test drive the car (same car I ended up buying) there wasn't a lag whatsoever. One thing I also forgot to mention. I've never had a Direct injection engine. My last car used CVT. So literally all of this is new to me.


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## jblackburn (Apr 14, 2012)

Merc6 said:


> There is way more nanny tech on these new age turbo cars to help it run 87 but usually timing is pulled. I have to find the article again that said EPA and manufacturers use a standard fuel across the board not commercially available that pretty much is a higher than 87 octane for its EPA and HP ratings. It's hard to sell a economy car with a premium fuel requirement. that whole low cost of ownership goes out the window. My car just didn't like 87 and wasn't recalled for it.
> 
> Like my Accord for example holds a whole 7 ish more gallons than my eco manual and with 87 Vs the eco on 93 it gets about the same 380-400 miles for same price point.


Something about the LUV/LUJ just never felt entirely right. I don't know if they just knocked from design and the engineers tried to tune around it or what. They played around with spark plug heat ranges between years as well, and as we all noticed, plugs could make a world of difference in responsiveness. They definitely improved the whole engine tune around the later years of the engine (it was also outfitted with different cam phasers). Not sure what made the difference. 

The LE2 seems to have gotten the tuning and transmission programming right out of the gate (except MT cars - finally got the chance to drive one, and they have horrible lag at the low end, feels even more detuned than the old engines below 2000 RPM). The auto transmission refinement is much improved, but still not entirely perfect. 

Some manufacturers, like Ford, give different HP/TQ ratings for 87 vs 91. Suppose this might be true for this engine as well, but it is nowhere near the seat of the pants difference to me that the 2012 was. That thing fell on its face sub 3000 RPM on 87.


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## DTook (Jul 5, 2016)

I run 93 from Costco pumps, they put more than regulated detergents in the fuel to keep your engine running clean. I Also work inside of Costco...


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## Merc6 (Jun 8, 2013)

DTook said:


> I run 93 from Costco pumps, they put more than regulated detergents in the fuel to keep your engine running clean. I Also work inside of Costco...


I also run Costco. The levels was up there with BP and Shell if the thread here resurfaces.


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## a2chris (Jan 13, 2017)

jblackburn said:


> There are a couple theories. Factory ring gap, detonation, or just bad piston design surrounding the rings are the top 3. Haven't heard of incompatible metals?
> 
> Given GM's troubles with the 2.0 and cracked pistons (engine tune) and melting pistons on the new 1.5 (also engine tuning), they do have a track record of it.


The 2.0 and new 1.5 might be because direct injection can still fire a much leaner charge but that means high temps. They should just switch to forged pistons in DI/TC engines.


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## jblackburn (Apr 14, 2012)

a2chris said:


> The 2.0 and new 1.5 might be because direct injection can still fire a much leaner charge but that means high temps. They should just switch to forged pistons in DI/TC engines.


Maybe. I can see their reasoning for not using forged in an everyday car turbo engine though - they are LOUD on cold startups. Ford, and I think most of the other manufacturers as well, use hypereuctic pistons in their turbo engines.

Toyota uses forged pistons in their 2GR-FE; sounds like the thing's out of oil for about 10 minutes of driving on a cold day.


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## MB2014LT2 (Feb 23, 2015)

I've run 92/93 in my 2014 2LT since I ran the gas out of it that the dealer gave me.


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## EricSmit (Dec 21, 2016)

93 octane. I sold myself the car for the dealer so I know that the first tank was also 93, because I filled the first tank.


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## Merc6 (Jun 8, 2013)

jblackburn said:


> Maybe. I can see their reasoning for not using forged in an everyday car turbo engine though - they are LOUD on cold startups. Ford, and I think most of the other manufacturers as well, use hypereuctic pistons in their turbo engines.
> 
> Toyota uses forged pistons in their 2GR-FE; sounds like the thing's out of oil for about 10 minutes of driving on a cold day.


Not sure of the new turbo Honda I4s but my N/A I4 says aluminum pistons and block with cast in iron cylinder liners.



EricSmit said:


> 93 octane. I sold myself the car for the dealer so I know that the first tank was also 93, because I filled the first tank.


 Yeah whoever has my old car has a full tank of Shell 93 and the premium door sticker. They can choose to go by it or not.


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## Merc6 (Jun 8, 2013)

Mphelps24 said:


> I apologize in advance for my stupid question. I know nada and I am trying to learn to understand and work on my car myself. I heard there is no benefit to using a higher octane gas if your car manual says it only requires regular. If there is or isn't a benefit would you mind explaining why? I see stuff online but I figure this is the real deal where I can obtain accurate answers.


That is normally true, but this car is different. My old Cruze wouldn't even run on 87 brand new. I had all kinds of issues until I went 93. Now my Subaru was 91 and up and you would blow the engine trying to get by on 87. Cruze is a 91 octane engine but for car sale purposes it can run on 87. Making a car only run on 91 would curb buyers from buying the car since people in this segment usually buy cars for low cost of ownership. Some Darts are 91 only and that hurt sales on top of them being Doge Darts.


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## a2chris (Jan 13, 2017)

Mphelps24 said:


> I apologize in advance for my stupid question. I know nada and I am trying to learn to understand and work on my car myself. I heard there is no benefit to using a higher octane gas if your car manual says it only requires regular. If there is or isn't a benefit would you mind explaining why? I see stuff online but I figure this is the real deal where I can obtain accurate answers.


One of my first cars had the timing advanced a little too much and would ping on 87 but not with 91 so that is what I ran until I got a timing light and fixed it. It also let me know which stations were cheating me when I would fill up with premium and it would still ping.
My 93 s10 with a 9.5:1 comp. ratio 4.3 Vortec v6 would get better gas mileage with premium so it cost the same per mile but I could go ~50 mile more per tank.

Pinging and pre-ignition are bad and can be caused by many things e.g. too much cylinder pressure (comp. ratio + charge pressure), too much timing advance, too lean of a fuel mixture, carbon deposits, or too hot of an engine. Higher octane fuel will resist it more and give you cushion of safety. 

I only run 87 in the winter when it is below 35f outside.

Anyway, each car may respond to high octane gas differently and you should try it for yourself. That being said, a 9.5:1 comp. ratio turbocharged engine should probably be fed more than 87 especially in warmer climates.

Hope this helps.


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## 295330 (Apr 25, 2017)

a2chris said:


> One of my first cars had the timing advanced a little too much and would ping on 87 but not with 91 so that is what I ran until I got a timing light and fixed it. It also let me know which stations were cheating me when I would fill up with premium and it would still ping.
> My 93 s10 with a 9.5:1 comp. ratio 4.3 Vortec v6 would get better gas mileage with premium so it cost the same per mile but I could go ~50 mile more per tank.
> 
> Pinging and pre-ignition are bad and can be caused by many things e.g. too much cylinder pressure (comp. ratio + charge pressure), too much timing advance, too lean of a fuel mixture, carbon deposits, or too hot of an engine. Higher octane fuel will resist it more and give you cushion of safety.
> ...


My 2011 does fine granny driving in warmer weather and winter on 87. But even in spring temps 65 to 70 degrees I occasionally hear light spark knock under load with low RPM's. This tells me the knock sensor and computer are past their ability to adjust to correct this. It also means the engine is not running at its peak performance. I've always been skeptical of a turbo and especially a small turbo requiring only 87 octane. But seriously, who would buy a Cruze 1.4 that required or even recommended premium? GM designed this as a econobox sedan and a world marketed one at that. They were obviously going to try and program it for 87 octane. Most probably could get by with 87 without a lot of issues. The question really is how much do you want to spend to have it run a little better? For myself I gradually raise octane as the temps go up. By summer I am all 93 octane until fall and move down to 89 mid grade. Can't prove otherwise to me this isn't a reasonable decision even if it costs a few bucks more per tank. Just like pure synthetic oil, its not required by GM but if you plan to keep your car at all beyond warranty. 
It might help prevent some problems down the road with the turbo and/or engine.


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## Merc6 (Jun 8, 2013)

jescott418 said:


> My 2011 does fine granny driving in warmer weather and winter on 87. But even in spring temps 65 to 70 degrees I occasionally hear light spark knock under load with low RPM's. This tells me the knock sensor and computer are past their ability to adjust to correct this. It also means the engine is not running at its peak performance. I've always been skeptical of a turbo and especially a small turbo requiring only 87 octane. But seriously, who would buy a Cruze 1.4 that required or even recommended premium? GM designed this as a econobox sedan and a world marketed one at that. They were obviously going to try and program it for 87 octane. Most probably could get by with 87 without a lot of issues. The question really is how much do you want to spend to have it run a little better? For myself I gradually raise octane as the temps go up. By summer I am all 93 octane until fall and move down to 89 mid grade. Can't prove otherwise to me this isn't a reasonable decision even if it costs a few bucks more per tank. Just like pure synthetic oil, its not required by GM but if you plan to keep your car at all beyond warranty.
> It might help prevent some problems down the road with the turbo and/or engine.


Yes, the HP and TQ ratings aren't on 87 or even pump gas. For me drivability outweighs saving a few bucks her and there.


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## ONE2CRUZE (Oct 18, 2017)

I know this is an older thread, when we first got the used 2015 LT2 a few months ago I was running 87 octane. Then after a few tank fulls and some 1800-2100rpm rattling just before the auto tranny shifts, reading a bunch of posts on a few other threads, decided to jump up to 89 octane. Just to see if there was a difference, been about 2 months now running the 89. I do notice a difference, the Cruze just seems to have a bit better pick up, runs and shifts smoother and just about no rattling. A real joy to drive.


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## nds76 (Aug 14, 2016)

I have always ran 87 octane in my Cruze. Sometimes Top Tier and sometimes not. I have considered trying 89 octane and see what happens. I read the first few pages of this thread and it seems split down the middle. As another said there are just too many variables in determining your mpg. So saying premium gas alone gives better mpg is somewhat misleading. It may be true or not be true.


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## ProDigit (Aug 31, 2015)

Regular. I occasionally put some premium in, when I'm expecting hot days (over 100F).


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## nds76 (Aug 14, 2016)

shawn672 said:


> I'm sad to see so many people running 87 when even GM confirmed you should run at least midgrade in the summer.. 89 should be a minimum year round though, its a lot safer and better for this platform than 87, it's a mere $1.00-1.50 more per fillup for better mileage, better timing (small bump in power), and safer for the forced induction motor


 I know your post is 7 years old but the price spread now is nearly a dollar from regular to premium so the extra cost would be much more than a mere $1.00-1.50 more per fillup.


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## obermd (Mar 3, 2012)

nds76 said:


> I know your post is 7 years old but the price spread now is nearly a dollar from regular to premium so the extra cost would be much more than a mere $1.00-1.50 more per fillup.


89 octane is mid-grade, not premium.


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## 91794 (Mar 25, 2015)

We run 87 octane in spouse's 2016 1.4T sonic stickshift, so I voted in this poll above.


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## jma20a (Dec 3, 2016)

i run 93 octane. 

quick question. can a stock '14 1LT fully loaded run E85? when i got my car(brend new) the salesman at the stealership told me my cruze would be able to run E85 stock, he said some can an some can't.


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## sillysleeper (Jan 6, 2018)

I use 93 from my Walmart/Sam's area, 91 if I'm not around town. I've always used at least 91, less chance of ping plus anything with forced induction appreciates it


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## snowwy66 (Nov 5, 2017)

After running 91 since day 1. I"m running 85 right now.


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## jblackburn (Apr 14, 2012)

jma20a said:


> i run 93 octane.
> 
> quick question. can a stock '14 1LT fully loaded run E85? when i got my car(brend new) the salesman at the stealership told me my cruze would be able to run E85 stock, he said some can an some can't.


No. It needs a tune and ethanol sensor to run it. 

Otherwise, Cruzes can only run up to E15 on the factory tune. 

Sent from my SM-G950U using Tapatalk


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## xbazzarex (Jun 5, 2016)

Ive used regular up until my last fill up, MPG did not improve at all(pretty much all highway miles on cruise control), however in the bit of stop and go around town i did, power and response do seem better. when my car was getting repaired i had a Malibu with the 1.5t and it was a bit quicker, though the malibu is boring as **** to drive.


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