# Max Speed on ECO 6 speed manual so far?



## savethewave (Dec 17, 2011)

I have noticed that at 65 mph, I am at 2,000 RPM. If I equate that out to 4,000 RPM I would be going 130 mph and so on. So at 6,000 RPM it would be 195 mph. Now I know that is stretching it, but was interested in how far anyone has pushed their Cruze.


----------



## iCruze2 (Dec 16, 2011)

I've only taken my lt/rs 6 speed auto to 90-100. I'm not as young as I used to be, I don't go faster than that anymore LOL. Too risky to get a ticket


----------



## AkotaHsky (Feb 11, 2012)

127MPH is all she has put out for me. Dont think it can do much more.

2012 ECO 6MT

Sent from my PC36100 using AutoGuide.Com Free App


----------



## iCruze2 (Dec 16, 2011)

AkotaHsky said:


> 127MPH is all she has put out for me. Dont think it can do much more.
> 
> 2012 ECO 6MT
> 
> Sent from my PC36100 using AutoGuide.Com Free App


Probably a lot faster with a tune


----------



## AkotaHsky (Feb 11, 2012)

iCruze2 said:


> Probably a lot faster with a tune


My tune will be in by next week. Then Ill let you know in a short while.

Sent from my PC36100 using AutoGuide.Com Free App


----------



## Vetterin (Mar 27, 2011)

I saw a thread recently about the Eco's top speed and I think it was a little north of 127 mph (132-136 if I remember correctly) however I will not be the guy that verifies it!


----------



## obermd (Mar 3, 2012)

One of the car mags tested the ECO and found a limiter at 130 mph. They were in 4th gear at that speed, so I don't know if 5th or 6th can go faster or if aerodynamic drag will overcome them.


----------



## iCruze2 (Dec 16, 2011)

obermd said:


> One of the car mags tested the ECO and found a limiter at 130 mph. They were in 4th gear at that speed, so I don't know if 5th or 6th can go faster or if aerodynamic drag will overcome them.


Yeah, I'm pretty sure the speed governor is edited out on a tune(or can be done).


----------



## bh04 (Aug 5, 2011)

I've hit 115 in my 11 6A LT


----------



## ErikBEggs (Aug 20, 2011)

I got to 110 with my tuned 2011 LTZ. Still had plenty of juice left. Got there pretty seamlessly


----------



## iCruze2 (Dec 16, 2011)

Somebody step up and do it tonight!!!


----------



## AkotaHsky (Feb 11, 2012)

No tune yet. Should be here early next week.

Sent from my PC36100 using AutoGuide.Com Free App


----------



## nobog (Oct 25, 2011)

"Tuning" won't help top speed - maybe a tiny tiny bit but for the most part don't expect anything measurable. Here's why:



Read it - twice.

Jim


----------



## iCruze2 (Dec 16, 2011)

nobog said:


> "Tuning" won't help top speed - maybe a tiny tiny bit but for the most part don't expect anything measurable. Here's why:
> 
> 
> 
> ...


My computer warned me this site isn't safe, so I can't read it not even once!

Also, cars are restricted by speed governors due to suspension/tire standards. The vehicle is locked in by the computer to only go to a certain speed. A computer tune WILL disable that feature and allow the car to go faster. So that BS about the tune not being able to correct it is true BS!!!


----------



## obermd (Mar 3, 2012)

Whichever car mag tested the ECO MT reported the top speed was computer limited, not drag limited. If tuning removes the ECU limitation, then it will allow a higher top speed. The LTZ was drag limited at 127, so unless the tune improves high end power, you won't see a much of a difference.


----------



## obermd (Mar 3, 2012)

nobog said:


> "Tuning" won't help top speed - maybe a tiny tiny bit but for the most part don't expect anything measurable. Here's why:
> 
> 
> 
> ...


MS Security Essentials reports Trojan:JS/BlacoleRef.W at the link you gave.


----------



## iCruze2 (Dec 16, 2011)

obermd said:


> MS Security Essentials reports Trojan:JS/BlacoleRef.W at the link you gave.


Good to know it's not only my computer. This guy trying to ruin our computers with false information to top it off!!!


----------



## Skilz10179 (Mar 22, 2011)

nobog said:


> "Tuning" won't help top speed - maybe a tiny tiny bit but for the most part don't expect anything measurable. Here's why:
> 
> 
> 
> ...


Not going to click your link, just going to say you're wrong.


----------



## obermd (Mar 3, 2012)

Skilz10179 said:


> Not going to click your link, just going to say you're wrong.


Skilz,

As a moderator, can you get the link deactivated to protect members from inadvertant infections?


----------



## Aeroscout977 (Nov 25, 2010)

Link removed.


----------



## nobog (Oct 25, 2011)

Sorry about that link - it was "good" last time I checked - but no, I am not wrong.

1. to double your top speed you need 8x the power
2. engine modifications will have a much greater impact on acceleration (which is directly related to power) than top speed 
3. air resistance and rolling resistance are the two main retarding forces against your vehicle - mainly air resistance.

Unfortunetly that link does not work, it explained the relationship of horsepower to top speed to drag coefficient. I believe I have the entire contents on my work computer and will post it Monday, Then you can think what you want. 

Jim


----------



## parish8 (Mar 11, 2012)

a tune is going to remove the limiter and add something like 50hp. it is going to pick up a fair amount of top end. no one is expecting the car to go twice as fast. 

i would expect to see something like 10+mph more from the previous unrestricted top speed with the tune but we dont really know what the unrestricted top speed is right now.


----------



## Camcruse (Oct 4, 2011)

Am I the only one who thinks what is this person thinking going 127MPH and trying to go higher?

The reward (which is nothing more than bragging rights) is not worth the risk.


----------



## ErikBEggs (Aug 20, 2011)

Camcruse said:


> Am I the only one who thinks what is this person thinking going 127MPH and trying to go higher?


Nope. Honestly, I try testing new versions of my tune on the street and almost crap myself and that is just to 60 mph. I save it for the track, but the Cruze never gets past 90 mph there. Sooo yeah... LOL I'm content just following the speed limit.


----------



## nobog (Oct 25, 2011)

*top speed*

This is rather long and it says _Copyright David Baker and Puma Race Engines_ everywhere but since his web site site gives a virus I will post it here, it is very good info - moderator please delete if you think nec but once you read it you will understand my comments about tuning and top speed, so here goes:


When a car moves along a flat road the engine has to work to overcome two main resistances - air resistance and rolling resistance (the drag in tyres, wheel bearings etc). The top speed of the car is determined by the amount of engine power available and the size of these retarding forces. The math to work out these equations for an actual vehicle are very simple. In order to calculate the top speed we need to work out the size of the retarding forces. 
[h=3]ROLLING RESISTANCE [/h]Defined as the force needed to just start a car rolling on flat ground this force is mainly a function of vehicle weight. You can measure it yourself fairly easily with a pair of bathroom scales or a spring balance. Just hold the scales vertical against the rear bumper and push until the car starts to move. You might find that once the car is rolling the force needed to keep it just moving falls slightly. This lower force is the number you are after. Copyright David Baker and Puma Race Engines 

For most cars the force in pounds can be estimated as follows: 
Rolling resistance (lbs) = vehicle weight (lbs) x 0.012 to 0.015 (I usually take 0.013 as a good average) 
Obviously if the tyres are flat or a wheel bearing is half seized this force can alter a fair bit but we will see later that it is air resistance that is the main obstacle to top speed so even a large error in the rolling resistance calculation won't matter much. Rolling resistance is taken to be a constant i.e. not varying with vehicle speed although this is really somewhat of a simplification. For an average car weighing 2500 lbs this force is therefore in the region of 33lbs. 
[h=3]AIR RESISTANCE [/h]This is a function of the frontal area (fA) of the car and its coefficient of drag (Cd). Often car magazine tests show these numbers and all manufacturers will have the data if they can be persuaded to release them. Most modern cars have drag coefficients between 0.3 and 0.4 with a few really streamlined ones as low as 0.28 or so. The Cd is a measure of how "slippery" a shape is as the air goes round it. Copyright David Baker and Puma Race Engines 
Frontal areas tend to lie between 19 and 23 square feet for European cars (we can exclude 4 wheel drive yank tanks and similar from this exercise because who cares how fast they go anyway?) 
The drag in pounds goes up with the square of speed and can be calculated from the following formula: 
Air resistance (lbs) = fA x Cd x 0.00256 x speed squared (speed in mph) 
Average family cars have a top speed of 120 mph or so these days so let's have a look at the size of this force at that speed. We'll assume the car has a frontal area of 21 square feet and a Cd of 0.35 

Air resistance (lbs) = 21 x 0.35 x 0.00256 x 120 x 120 = *271 lbs* (at 120 mph)

As you can see this is a much larger force than the rolling resistance. In fact rolling resistance only makes a major difference to vehicle dynamics at very low speeds (under 60 mph or so) and means that heavy cars use more power and therefore have poor fuel consumption at low speeds. At higher speeds the air resistance becomes paramount and so even heavy cars can show good fuel consumption if they are well streamlined. 
[h=3]POWER REQUIRED [/h]The final step is to relate the drag figures above to the power required to overcome them. If we add rolling resistance and air resistance together we get total drag in pounds. Power required is then calculated as: 
Power (bhp) = Total drag x mph / 375 
We could if required split the power into the amounts needed to overcome each drag separately. The equations would then become: 

Power to overcome rolling resistance = weight x 0.013 x mph / 375 

Power to overcome air drag = fA x Cd x 0.00256 x mph cubed / 375 

Hopefully something of major importance should be clear from the above. We already know that it is air resistance that is the major element in this equation and we can see that we need to incorporate mph cubed in the power equation for air drag. As a simplification therefore we can say that power required is closely related to mph cubed - i.e. to double the speed of a vehicle we need 8 times the engine power. Alternatively we can express this as top speed is a function of the cube root of engine power. This means that engine modifications will have a much greater impact on acceleration (which is directly related to power) than top speed. Also that is why an old engine which is down on power might accelerate slowly but still have close to its original top speed. So next time your mate tells you in the pub that he put a K&N air filter in his car and the top speed went up by 10 mph you can explain exactly why that isn't going to be very likely. 
[h=4]Examples: [/h]Let's say we want to increase the top speed of a car by 10% - how much extra power do we need? Increase in power required is related to increase in speed cubed - i.e. to 1.10 cubed = 1.33. So we need about 33% extra power to achieve 10% increase in top speed. Copyright David Baker and Puma Race Engines 
Alternatively let's say we tune an engine and achieve 10% extra power - how much will top speed go up by?. Speed is proportional to the cube root of power - i.e. to the cube root of 1.10 = 1.03. So speed will only increase by about 3%. 
What this all means for you hopefuls who bolt on go faster goodies like chips, exhausts and the like. You will see hardly any increase in top speed. To get significant increases in top speed requires serious engine surgery. 

*IMPORTANT NOTE:* 
The power calculated above is power delivered to the wheels and NOT flywheel power - i.e. we need to allow for transmission losses to get back to engine power required. Transmission losses will be the subject of another article but for brevity we can take the following as good assumptions. Front wheel drive cars will lose 15% of the engine power as transmission and tyre losses and rear wheel drive cars will lose 17%. This assumes manual gearboxes and I could care less how fast autos or 4 wheel drive cars go ! 
So divide by 0.85 or 0.83 as appropriate to convert from wheel bhp to flywheel bhp. 
[h=3]TABLE FOR AN AVERAGE CAR [/h]The math above is so simple it should only take a few minutes to put together a spreadsheet to work out the power required at any speed for your own car if you have the weight, Cd and fA. To give an idea of power levels required for an average car I have put together the table below. It assumes a car weighing 2500 lbs with driver, 21 square feet fA, 0.35 Cd and front wheel drive so transmission losses are 15% of the flywheel power. The other thing that can be estimated from this power requirement is the fuel consumption. A well designed petrol engine running on a lean cruise fuel/air mixture should have a specific fuel consumption of between 0.50 and 0.55 lbs weight of fuel per horsepower generated per hour. At very low throttle openings the consumption will be a tad worse because the cylinders aren't filling completely which hurts efficiency. This means that small engines will always produce better economy than large ones, partly because at a given road speed they are operating closer to full throttle and partly because their smaller (and/or fewer number of) cylinders will waste less power, and fuel, in overcoming internal friction. An imperial gallon of fuel weighs about 7.5 lbs (those puny American gallons are about 20% smaller). From the speed and flywheel power requirement we can now calculate the expected fuel use per hour and therefore the mpg. In practice the estimated mpg for very low speeds will be optimistic because most engines aren't working very efficiently at such small throttle openings. The same will apply to the mpg for very high speeds because most engines are getting close enough to full throttle to require a richer full power fuel mixture up there. The table is therefore only a rough guide of course and obviously the real world steady speed economy is different for every car. It hopefully makes the point though that the best way of improving your mpg is just to go slower! Copyright David Baker and Puma Race Engines 

SPEED (MPH)
FLYWHEEL POWER
REQUIRED
MPG
30
5
97
40
8
76
50
12
60
60
19
48
70
27
38
80
38
31
90
52
26
100
69
22
110
90
18
120
114
16
130
143
14
140
176
12
150
215
10
160
258
9
170
307
8

[h=3]IN THE REAL WORLD [/h]People are forever claiming how fast their cars go based on speedo readings. Most speedos read way fast - the law allows a 10% error and most manufacturers set speedos somewhat fast so that you won't get get done for speeding and then sue them. I have tested a number of cars and the average error is about 5% to 7% fast - i.e. when the speedo shows 100 mph you are really doing about 93 to 95 mph. Many magazines do a speedo accuracy test as part of their report - have a look at Autocar tests or similar. Trying to calculate engine power based on speedo readings is a waste of time unless you know the speedo error. Small errors in measured top speed lead to much larger errors in calculated horsepower due to the cube law above. It is easy enough to find out what this speedo error is - any rolling road should have a calibrated roller which you can use to test speedo mph against true mph - ask the guy to do this for you next time you have your car set up. Copyright David Baker and Puma Race Engines 
Another way is to time the car against the motorway marker posts which are 100 metres apart. I find this is a perfectly accurate way of checking things if you hold a steady speed for half a mile or so (8 posts). You can do the math yourself though. 
Also bear in mind that if the wheels and tyres are non standard sizes then the speedo will not read the same either. Even tyre wear makes a difference with new tyres reading about 2% slower on the speedo than worn out tyres due to the change in diameter due to the tread depth. I had to recalibrate my speedo after fitting new tyres to get complete accuracy again. 
The other factor that always comes into play when anyone tries to find out the top speed of their car is a psychological one - you tend to ignore tests that show a low speed and only take any notice of ones where the car goes well. This tends to mean that the average person remembers the speed when the slope was slightly downhill and there was a tailwind - any other occasion gets forgotten as being a bad test. This isn't helped by the fact that a level road tends to appear slightly uphill to most people so when they pick a stretch of motorway to have a thrash on it is often a downhill stretch. 
[h=3]GEARING [/h]To actually achieve the theoretical top speed that a car with a given drag and a given engine bhp should be capable of does of course require that the car be geared correctly. In other words the engine needs to be at the rpm at which it produces maximum power at the theoretical top speed. However, having said that, it is all much less critical than people tend to realize. Because top speed is fairly insensitive to engine power as shown above, there will be only be a small decrease in speed for a relatively large drop in engine power. Most engines have a broad spread of power around peak rpm - for 500 rpm either side of peak the power falls very little. So provided that the gearing is close enough to fall into this 1000 rpm band at the theoretical top speed the car will usually achieve it or very close to it. Copyright David Baker and Puma Race Engines 

So for a car producing peak power at 6,000 rpm you will reach almost the same top speed anywhere in the 5,500 to 6,500 rpm area. In other words there is something like a 15% spread of possible gearing in top gear that will do the job. That is also why so many cars reach very similar top speeds in both 4th and 5th gear - it's just you get there a bit faster in 4th. For very 'peaky' highly tuned engines where power rises and then falls very abruptly, the choice of gearing becomes more critical. This is only of real concern to race type engines though.

As an aside the whole business of gearbox ratios for road cars is very much over-rated. There is a current fad for expensive 6 gear conversions which make next to no difference to the overall performance of the car. I might write an article on it one day but for now I will content myself with advising anyone considering such a mod to forget it. Spend the money on serious engine work instead. To go into the math of why such conversions don't show much benefit is too time consuming for now. Copyright David Baker and Puma Race Engines 
[h=3]SUMMARY [/h]It takes a lot of power to increase the top speed of a car significantly. The cube rule above is a good guide. You can't just change the gearing as so many people seem to think. If you look through a few magazine tests you will see that most cars show top speeds that follow very closely the figures shown in the table above. One more thing to bear in mind is the way magazines test cars. Often they do not have long enough test straights to reach the absolute top speed and when banked tracks are used these also tend to scrub off a few mph. Most of this applies only to very fast cars - i.e 150 mph plus machines. You have to read between the lines to see whether the tester thinks that the top speed shown is a fair representation of what the car in question could do.


----------



## Patman (May 7, 2011)

Had mine to @115 never saw a reason to go faster. Besides traffic/hills/police kinda put a damper on the activity!


----------



## spacedout (Dec 7, 2010)

Pretty old thread.... Seems the OP thinks leaving the car in 6th will get your highest top speed, this is not the case. I have had my auto to 105MPH passing a car on the highway, that was in 5th gear. Even then quick acceleration was non-existent, I should have red lined 4th before ever being in 5th.

I don't know if there is any computer limited speed but my guess with a 2012+ auto top speed might be in 5th if you get the RPMs up enough first. Pretty sure shifting to 6th with its 0.75 ratio would actually put so little power down you loose speed.


----------



## smcruze12 (Jan 21, 2013)

I got 131 / 211 kph in my 12 2LT 1.4 T. No tune just ZZP short ram


----------



## NickD (Dec 10, 2011)

If you watch programs on TV like Top Gear, will drain a 25 gallon tank in ten minutes driving over 200 mph. So what is your average mpg gallon when driving your Cruze at a low 110 mph?

Ha, I will take your word for it. Just like taking their word for my, my Supra is governed for a top speed of 167 mph.

Know my old 30 Olds would do over 90, 37 would top at 97, quit when my 41 Buick did over 110 mph. Use to be important to me way back when, but not anymore. Could fly a Piper Archer at 165 mph legally at 300 feet as long as I was 500 feet to the right of an interstate. That was cool.


----------

