# Is there a benefit to higher octane in 1.8 ls?



## Rauen (Apr 27, 2013)

Just wondering if this could help the fact that I can kind of feel the idle in my drivers seat (I'm well aware tat this could be a thermostat issue, I'm having it checked on my first oil change) and the fact that my car runs like crap when my air is on lol


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## brian v (Dec 25, 2011)

I would imagine that there would be many benefits to using a higher octane fuel , 1 a higher octane produces more energy . Better gas mileage should be one of the first attributes .


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## jblackburn (Apr 14, 2012)

Checked your spark plug gaps? My 1.4 idle smoothed out immensely when I regapped them. Theres a thread in the how to section. 

And it does also help a bit when I run higher octane with the AC on. 


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## obermd (Mar 3, 2012)

My son and I tried 87 octane in Penguin LS and immediately switched back to 91 octane. The 1.8 engine in the LS definitely runs better and with more HP on 91 than on 87.


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## ErikBEggs (Aug 20, 2011)

A 138 HP N/A engine is unlikely to benefit from higher octane unless it is tuned to do so with an aftermarket tune. Your owners manual says 87 octane so it will run fine on it. The 1.8L is not forced induction (so no high compression), so there is no benefit.


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## CyclonicWrath (May 14, 2013)

Still will be a benefit maybe not as much as a 1.4t but yes just try a fill up after you are empty I bet you will feel a difference


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## ErikBEggs (Aug 20, 2011)

Don't waste your money, OP.


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## Rauen (Apr 27, 2013)

jblackburn said:


> Checked your spark plug gaps? My 1.4 idle smoothed out immensely when I regapped them. Theres a thread in the how to section.
> 
> And it does also help a bit when I run higher octane with the AC on.
> 
> ...


no but I've been told the se by others as well. What is it like 35?


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## jblackburn (Apr 14, 2012)

Rauen said:


> no but I've been told the se by others as well. What is it like 35?


Try .030" for a 1.8. Nearly all reported plugs from 11-12 model years were set under .025" from the factory. 

Try a tank of 89 and see if it behaves any better (after regapping the plugs). No need to go for all out 91. 


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## Calintz (Jul 21, 2011)

You won't benefit with race gas unless you're tuned. The 1.8L tune is all about timing if the ecu detects a higher octane it will adjust the timing accordingly in which in return create more power not much but you will feel it.

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## Calintz (Jul 21, 2011)

jblackburn said:


> Try .030" for a 1.8. Nearly all reported plugs from 11-12 model years were set under .025" from the factory.
> 
> Try a tank of 89 and see if it behaves any better (after regapping the plugs). No need to go for all out 91.
> 
> ...



Especially for the manuals you will feel a difference in reponse

Non tuned I recommend 0.035

Tuned should set it to 0.030 

The 1.8L feels better with 93 octane even when I wasn't tuned.

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## obermd (Mar 3, 2012)

brian v said:


> I would imagine that there would be many benefits to using a higher octane fuel , 1 a higher octane produces more energy . Better gas mileage should be one of the first attributes .


Common misconception - higher octane gas in general contains fewer BTUs of energy per gallon. What higher octane gas has is a reduced chance of premature ignition which is the cause of engine knock. The Cruze's ECU listens for pinging (light knock) and retards ignition timing to protect the engine. Retarding the ignition timing has the side effect of reducing HP and fuel burn efficiency. It appears that the 1.8 EcoTec engine also prefers 91 octane over 87.


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