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Well, I'm new to my car, but know it well enough to know how it normally behaves. Today the weather hit 89 degrees - the hottest weather I've been in with it. I've never really felt like I needed to ask this car for more power (the 1.8 was a different story when I test drove it) in around-town driving, but today the lag was HORRENDOUS after shifting to the next gear at like 2500-3000 RPM. I felt like I needed to rev the heck out of it to find the power band since it didn't seem to be picking up with power til 2500 RPM instead of the normal 1800.

I owned a turbocharged Volvo before this model, and it was recommended that you use 91 octane in it (87 was the minimum). I tried 87 and it ran like crap, especially in the summer with AC on, so I usually used 89 and the powerband was pretty good. That one was a high-pressure turbo where it didn't even pick up til 2500 RPM with power, but the AC always exacerbated that lag to an extent.

My question to you guys is 1) Is this normal for these cars (AC creating a lot of drag on a really tiny engine?) and 2) Do they do any better in the summer time if I were to run say, 89 or 93 octane in it?

Thanks in advance!
 

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Run higher octane. The 1.4T engine in the Cruze has a lot of factory settings that allow it to run on lower octane gas, but it really wants 89 or 91. Try boosting your octane one grade at a time to see the differences.
 

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1) yes
2) yes
LOL. Welcome to my world. In a nutshell, hot Intake Air Temperature has less oxygen per mass (= less power) + the tune automatically adjusts the car to "run worse" (timing, etc.) when it sees hotness, to protect itself (much higher chance of knock). Also, not only is the a/c compressor working harder (load = drag) but the a/c condenser becomes hot and affects the inter-cooler which is behind it and sandwiched between the radiator. Basically it's a huge domino effect of running like crap in hot weather as with all turbo cars, especially those with tiny engines and turbos. Use 93 octane. Trust me.
 

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Right, all the same reasons with the other car. I'm sure running AC on a 1.4 vs a 2.3 also makes some difference I'm not used to yet.

I'll give 89 a try next tank and see how it does.

I'm hoping it will make enough of a difference as it did with the Volvo to not have to justify paying $.35 more per gallon for 93 vs 87 when it's already $4/gallon. That was one of the reasons I bought this car.

I don't drive like a speed demon, but I just want consistent response when I put my foot down to scoot into another lane on the highway.

Thanks for the replies!
 

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Yes - got my 2011 ECO 6M on July 1st last year so know what you mean about poor response, especially with the AC cranking. I agree with the higher octane helping. Also give the engine some time to fully break in. You might also look into the Trifecta Tune, even in ECO mode it greatly improves the driveability.
 

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I've owned over a dozen forced induction cars. I wouldnt say this holds true with every car. But, most of the turbo or supercharged cars can get heat soaked intercoolers, which, like explained above, will retart timing and even lower the boost to keep engine knock to a minimum. I put one tank of 87 in my car, the other 2 have been 91. Ill probably just keep pumping 91 into it.
 

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Run 93 in it. When I bought mine, they filled it with 87. Car had 4 miles on it, and it was a really hot day. I kept noticing the car was surging a bit on acceleration and seemed to lag (I could tell turbo would build boost, then ecu cut boost and come back). I emptied the tank the next day and ran 93. World of difference. Gas mileage greatly increased too.

Personally, any turbocharged car I have owned/dealt with would only get 93 minimum. Any grade lower meant driving under no boost or a hold over to get somewhere. Yeah, the ecu can adjust for octane grades, but it benefits the engine to run 93 especially with how this engine is in boost so much.
 
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I've noticed a big difference with the A/C on high versus any of the other speeds. The A/C compressor is clutched and variable displacement, and running it on high sets the compressor load to max. Add in the electrical load from the high fan speed (significant). And then figure than you usually only run max A/C when it is really hot out and you can see why it is a worst case scenario. But then again it becomes a bit of a challenge to keep the boost up - have to shift a lot!
 

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What everyone said. It is pulling timing. I noticed that last summer too.

Personally, any turbocharged car I have owned/dealt with would only get 93 minimum.
No 91? 91 Octane works fine if you have access to it. Sunoco sells 91 and 93, but 91 $.10-$.02 cheaper.

Also, the air conditioning stuff I can't say I've noticed screwing with the power....
 

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Gonna go against the grain here and say unless you are knocking or in a high temperature environment on a regular basis, the best performance will be made on the lowest octane level that doesn't cause detonation, i.e. 87 Octane, non-crap gas of course. Higher octane on a stock tune doesn't make much sense to me other than you will get a less explosive mixture and ultimately lower ECTs, so my guess is this is why those of you in a hot environment see benefits by increasing octane...you keep the ECU timing in the optimal range at which it doesn't pull any timing...which is good right, but otherwise, in boost, or cruise, the car is tuned for 87, the high octane maps in the ECU are set for 87, going above that untuned just will give you a little bit of safety margin so that the random knock that does occur doesn't move you toward the lower octane map, which can happen over time and performance will suffer, I still don't think it's worth the extra 20-30 cents a gallon.

As far as boost is concerned, the same is true, there is just less timing in those high cyl air mass cells to compensate for the increased density...which means under boost in normal driving conditions 87 should yield max power and economy.
 

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As far as boost is concerned, the same is true, there is just less timing in those high cyl air mass cells to compensate for the increased density...which means under boost in normal driving conditions 87 should yield max power and economy.
It should, and it does in 95+% of circumstances.. but as temperatures get to 90+, it does have heat soak and timing issues. It won't knock on 87, but it will pull timing. We have data logs for it, experiments, even articles on it. So technically it isn't doing engine damage because the ECU compensates, but it does cause MPG / performance penalty in hot situations. The heat soak is less about the intercooler being poor as it is the position and type of intercooler it is. It is air-to-air, so high ambient temps really affect how easily it gets heat soaked. Make sense?
 

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Mine knocks slightly at 87 when going up hill, even in winter. That may also be partly because of the altitude. Finally found 91 and switched to it. So far on this first tank of 91 I'm over 46 MPG with no other changes to my driving. I was over 48 until the weekend chores driving hit.
 

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What everyone said. It is pulling timing. I noticed that last summer too.



No 91? 91 Octane works fine if you have access to it. Sunoco sells 91 and 93, but 91 $.10-$.02 cheaper.

Also, the air conditioning stuff I can't say I've noticed screwing with the power....

Well Sunoco is the only place around the state, well where I drive throughout state, that has 91. For the Cruze, I would run 91, but 93 is just more readily available to me.


Another thing I noticed was spark plug gap. I decided to toy with the gap, and move it to .034. Initially I had a nice torque feel but power felt off. Drove it a bit more to see if ecu was being affected by the change, and get it to learn. Well it runs so much better now. Gas mileage is up from 37mpg being a bit easy on it, to 40mpg driving normal and sometimes a bit hard (highway/city mix). Also checking into the the potential that there is arcing inside plug boot. Did notice a couple springs were bound up and not contacting spark plug completely.



@ECOmaniac, how exactly do you say higher octane is less explosive? All it is is fuel with a higher flash point. The Cruze can handle 87, as ecu will pull timing and could even cut boost being electronically controlled. The higher intake temps, and cylinder pressures from boost, would benefit from higher octane. 91-93 would bring the best out of the engine. Which one is optimal would require datalogging them. You could get same power/mpg figures from them, so if that was the case, 91 would be the thing to go with. 93 is readily available to me everywhere I go, so I just stick with it.
 

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One good idea to help mitigate the need for the AC to work as hard is to get the windows tinted, and when its parked outside, put up a sun shield.
 

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It should, and it does in 95+% of circumstances.. but as temperatures get to 90+, it does have heat soak and timing issues. It won't knock on 87, but it will pull timing. We have data logs for it, experiments, even articles on it. So technically it isn't doing engine damage because the ECU compensates, but it does cause MPG / performance penalty in hot situations. The heat soak is less about the intercooler being poor as it is the position and type of intercooler it is. It is air-to-air, so high ambient temps really affect how easily it gets heat soaked. Make sense?
Confused because this is what I said in the first paragraph, I agree! Not trying to refute the temperature issue, it's the exception to the rule so to speak. I tune my own cars and I tune them well, I don't do anything without solid evidence either for or against a change. I data log everything. The car I traded in for my ECO, 08' Grand Prix GXP 5.3L LS4, I removed the entire IAT/ECT timing reduction for all temps within standard operating range plus the next two iterations on the high temp end, resulted in increased performance in hot conditions with zero knock or overtemp conditions.. More than likely I'll be doing the same in the Cruze, if the data supports it...
 

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@ECOmaniac, how exactly do you say higher octane is less explosive? All it is is fuel with a higher flash point. The Cruze can handle 87, as ecu will pull timing and could even cut boost being electronically controlled. The higher intake temps, and cylinder pressures from boost, would benefit from higher octane. 91-93 would bring the best out of the engine. Which one is optimal would require datalogging them. You could get same power/mpg figures from them, so if that was the case, 91 would be the thing to go with. 93 is readily available to me everywhere I go, so I just stick with it.
Explosion was the wrong word to use, a gallon of 91 octane gas has less potential energy than a gallon of 87 octane gas for the same amount of base timing advance, which is exactly why gains are seen by increasing timing with higher octane and why knock is seen when advancing the same amount of timing with a lower octane gas. It's all about BMEP.

The OEM recommendeds 87 octane, not "it can handle it", it should not be pulling any timing on base timing tables if it was tuned properly by the OEM...what you are suggesting is that every person who drives off of the lot with a tank of 87 is going to knock considerably until the ECU timing is adjusted, I can bet dollars to pesos this isn't true. The OEM "high" octane tables should be set for the recommended octane level, i.e. 87 octane, unless you get a $hit tank of gas, or are in weird loading scenarios, you shouldn't knock. I still stand by the notion that 87 is sufficient for 90% of Cruze owners.
 

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The more we talk about data logging and tuning the more annoyed I get with HPTuners not having support yet. I can't wait to tap into this ECO.
I thought I read on the HPTuners board that they added support for the 1.4L.
 

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I thought I read on the HPTuners board that they added support for the 1.4L.
Negative - still in the works. There is a 1.4T thread that Chris @ HPTuners has been updating it sounds like they are finalizing things but haven't given a time table. On that note I'm going to ask for an ETA..
 
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