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Discussion Starter · #1 ·
Hi,

So, there already are aftermarket intercooler threads on here I've read (mostly).

I still have a few questions:

1- Can a larger than stock, aftermarket intercooler be installed without any updates to the FI system or ECU?
2- Where does the ECU receive the IAT (Air intake temperature sensor) signal? Is it after the turbo/ before the intercooler, after intercooler, or inside the 'carburetor'?
3- The weather in SoFlo is way too hot. I want to install a larger intercooler, to have better performance mainly during extreme hot days like over 100F. Will it work without any ECU mods?
4- Will my MPG numbers be affected by installing a larger intercooler without any other modification to the vehicle?
5- Will I notice performance gain, or performance hesitation switching the stock intercooler for a larger one, due to the air being cooler and perhaps the car running leaner?

Thank you!
 

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I don't have answers to your questions, but I think your first question should be, "How efficient is the stock intercooler?" It's always wise to know the baseline before you start modifying. I have viewed the temps on my torque app, and it seems to me that the stock intercooler is very efficient - usually only a couple degrees. Maybe you should get a scanguage and check the temps. It would be interesting to see what you get in SoFlo on a hot day.
 

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Discussion Starter · #3 ·
The stock intercooler works fine under 85F. And has a marginally lower performance between 85-95F. But above 95F loses too much efficiency. Above 100F it's even hard to accelerate in 5th gear to 75MPH on an interstate on-ramp (what would be ok at 80F in 6th, is not even at 100+F in 5th).
Once temps get above 105F, the car is hopelessly underpowered, and feels like you're riding a 1.2 liter NA on a cold day on the highway.

The ZZPerformance intercooler is much larger than stock.
A lot of users on the forum have suggested to just change the hoses to metal pipes, but I don't have any specs for that. The metal should easier cool down the incoming air than the rubber hoses that insulate the heat.
 

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People usually go ZZP because the CX one has issues with couplers leaking. Haven't much info on the BNR one, just the ZZP one is listed on their site.
 

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Hi,

So, there already are aftermarket intercooler threads on here I've read (mostly).

I still have a few questions:

1- Can a larger than stock, aftermarket intercooler be installed without any updates to the FI system or ECU?
2- Where does the ECU receive the IAT (Air intake temperature sensor) signal? Is it after the turbo/ before the intercooler, after intercooler, or inside the 'carburetor'?
3- The weather in SoFlo is way too hot. I want to install a larger intercooler, to have better performance mainly during extreme hot days like over 100F. Will it work without any ECU mods?
4- Will my MPG numbers be affected by installing a larger intercooler without any other modification to the vehicle?
5- Will I notice performance gain, or performance hesitation switching the stock intercooler for a larger one, due to the air being cooler and perhaps the car running leaner?

Thank you!
I will do my best to answer all of your questions based off my knowledge of multiple platforms.

1 & 3- Yes. You can install a larger aftermarket intercooler without needing a tune. However, for maximum benefit of the new part, it is recommended.

2- My guess would be before the turbo, however don't quote me.

4- It shouldn't change, however its possible since you are changing the make up of air density entering the engine.

5- Short answer, no. You will not notice a performance GAIN, as with the stock tune, your ECU limits you to the stock map in regards to hp/tq. What you will notice, is less bogging down due to heat soak.

As for what you should get, CX Racing is absolute garbage. Had one on my brother's Cruze, and it was a horrible fitting, cheap kit. I've never heard anything negative about the ZZP kit, however I've heard mixed reviews on their other products, mainly their big brake kit, and I've heard their customer service isn't that great.

My personal recommendation would be BNR [Bad News Racing] through Jerry. I don't know if his kit has been real world tested against the ZZP kit, however he is a Florida local, and the main guy to go to for a tune, which will help you out in the long run as he will be able to assist you better than ZZP.
 

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The stock intercooler works fine under 85F. And has a marginally lower performance between 85-95F. But above 95F loses too much efficiency. Above 100F it's even hard to accelerate in 5th gear to 75MPH on an interstate on-ramp (what would be ok at 80F in 6th, is not even at 100+F in 5th).
Once temps get above 105F, the car is hopelessly underpowered, and feels like you're riding a 1.2 liter NA on a cold day on the highway.
Maybe you've addressed this, but the question is what is the temperature difference between the outside air and the air exiting the stock intercooler? And can a aftermarket do enough better to make a performance difference? After all, short of adding ice, you can't make the air going into the engine cooler than the outside air. The best you can do is make the difference as small as possible. But at some point you reach the "diminishing returns" where the cost of improving it is too much for what you get.
 

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Discussion Starter · #7 · (Edited)
I presume that the stock intercooler isn't working optimally, because of the heat soak issue.
Heat soak should not be a problem when the intake air is nearly constant.
The higher outside temperature, the lower the efficiency of the intercooler is, and I think it's saturation point is around that 95-100F range (where the efficiency curve changes more drastically).
An intercooler the size of stock, will never cool down the air to outside temperatures. There's always a differential. That differential will be smaller with a better, larger intercooler, but I don't know if the ZZ is better than stock or not.

One thing mentioned, on other forums as well, is that the intercooler hoses are heat-insulating, and that changing part of the hose with aluminum tubes, and keep eg: rubber elbows, should improve efficiency. Especially the hose coming from the turbo into the intercooler needs to be swapped to aluminum for increased cooling, as the highest temperature delta is right after the turbo.

Going over the numbers again,
my car has 50k miles on it, and probably has another 50k miles to go, before I will want to buy a new one.
At the current rate of $2.25/gal, and with predictions of it rising to $3.25 a gal in the near future, for a new car, to change the intercooler to have +2 MPG at best, your budget will be about $500. For a car with 50k Miles on it, $250 is the budget, that within 100k miles the car will earn back in fuel savings.
That is with the positive outlook of about 2MPG gain; but fuel costing over $2,50 a gallon will actually make it easier to gain back the money faster.

So I'm looking at a $250 budget here.
I'm not going to find an intercooler for that price that's worth trying out.

My car is a 2011 eco model.
I don't know if I have the same issue as others have, a hose connecting the turbo to the intercooler that's insulating.
If that is the case, I might want to look at swapping out that inlet hose for an aluminum one that fits the stock cooler, as that will help cool down the hottest part of the air from the turbo.
If there are ways to further cool down the hose, like by welding or soldering a heat sink on it, or mounting it on a part of the steel frame that is relatively cool compared to the air, it would help as well.
 

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The higher outside temperature, the lower the efficiency of the intercooler is, and I think it's saturation point is around that 95-100F range (where the efficiency curve changes more drastically).
Um, how are you calculating efficiency? The formula is ( t(in) - t(out) ) / ( t(in) - t(ambient) ). As long as the airflow is cooled to near ambient, the efficiency is good. As long as t(out) tracks t(ambient), the ambient temperature will not affect efficiency. That's not to say it won't affect engine performance, since a higher air temp going to the engine is still an issue, but there's only so much you can do when the ambient air is hot.

Where efficiency falls off is with higher RPM. Intercoolers struggle with the higher airflow - there's more hot air to cool and less time to do it in. So you might want to consider how much of the time you spend at higher RPMs.

You might be interested in this page that showed a aftermarket intercooler didn't help a BMW until 4000 RPM.


An intercooler the size of stock, will never cool down the air to outside temperatures. There's always a differential. That differential will be smaller with a better, larger intercooler, but I don't know if the ZZ is better than stock or not.
Yes, there will always be a differential. But unless you've looked at t(out) - t(ambient), you won't know if the intercooler could be doing better or not. If it's within a few degrees, put your money somewhere else.

Now, I haven't read your other posts to know what kind of gas you buy, but at those temps, I'd be putting the highest octane I could find into the car. 93 if you can find it. 91, otherwise. It will make a world of difference. While the car is rated for "regular" the stock computer will take advantage of premium. With high ambient temperatures, the car will be forced to pull the ignition timing and/or boost to prevent destructive pinging. The Cruze in 100F weather will show it's appreciation for higher octane.
 

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Discussion Starter · #9 · (Edited)
I don't calculate the temps.
I notice the performance loss as I ride.

The biggest loss isn't from pre-ignition,
Getting higher octane fuel is not going to help the performance loss at hotter outside temperatures, because it's not nearly as hot that the engine is pinging, or else the engine temperature should rise, and it doesn't.
Getting hi-octane is only going to help if you get BP or Shell premium, as they have nitrogen infused fuels (burn harder).
Shell gives about 5% and BP 10% more power, or efficiency, depending how you ride it, but that's also true for other vehicles without turbo or intercooler.
Even scooters benefit from the same power increase.


The power loss is not linked to the use of 87-octane fuel, but from hot air, being less dense, entering the engine, thus the FI system injects less fuel to keep the correct A/F ratios, that results in the biggest loss of power.

Despite the air being hotter, which would promote pinging, it is also less dense.
And with less dense air and fuel in, compression will result in less PSI than when air is colder and denser.

Part of cooling that air more down, will help make it more dense.
And the hose between turbo and intercooler is the area where most heat can be soaked out of.

As far as high RPM,
I notice that at 80F, the turbo kicks in at just over 2000RPM, to ~2700RPM.
At 100F, it kicks in around 2500RPM to 3000RPM.

As the air is cooled in the intercooler, it shrinks, and probably causes a pressure drop; forcing the turbo to reach higher RPM to be effective.

As for engine RPM, on the on-ramp to the interstate, to 75MPH, in 5th gear, that will be 3500RPM.
I know that the engine doesn't perform well above 3k RPM, so I always try to keep it under. But it has almost no acceleration in 6th.
So the added engine friction and heat losses in (manually forced) 5th gear, compensate for the added torque compared to accelerating it in what the automatic gearbox would recommend in 6th gear.
Even at 105F, 6th gear functions well to maintain speed, but it no longer has any overtaking power, or acceleration at these speeds.
 

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You might want to read this thread: http://www.cruzetalk.com/forum/34-gen1-1-4l-turbo/2992-gm-confirms-use-91-octane-fuel.html

Or for that matter, any of the numerious threads about octane on this board.

The Cruze is octane sensitive. In part because it's was originally designed for higher octane until the sales department overruled the engineers and made them adjust the programming.

Bottom line, octane DOES make a big difference in this car. It will only cost you a few bucks to find out for yourself on your next fill-up.

And if you decide to go for a tune because you feel the stock programming doesn't take advantage of the mods, you'll probably end up with premium anyway.
 

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Discussion Starter · #11 ·
Explain exactly how higher octane is in any way going to affect performance on the cruze?
That car isn't pinging. The engine block and air intake remain relatively balanced, regardless of the outside temperatures.

I already ran my car with Premium fuel.
But Premium fuel from off brands like racetrack, Mobil, Esso, and other no name brands, do absolutely nothing performance wise.

The only 2 brands are BP and Shell, and that's not because the fuel is Hi-Octane.
If anything, higher octane should lower MPG, when riding the car moderately, because it takes longer to combust.
 

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Explain exactly how higher octane is in any way going to affect performance on the cruze?
That car isn't pinging. The engine block and air intake remain relatively balanced, regardless of the outside temperatures.

I already ran my car with Premium fuel.
But Premium fuel from off brands like racetrack, Mobil, Esso, and other no name brands, do absolutely nothing performance wise.

The only 2 brands are BP and Shell, and that's not because the fuel is Hi-Octane.
If anything, higher octane should lower MPG, when riding the car moderately, because it takes longer to combust.
The Cruze was designed to run on premium. It has been confirmed multiple times before from factual data, not just anecdotal. The computer will pull timing and boost like crazy in hot weather with 87 octane to PREVENT pinging, hence the reason it's not. Higher octane gas does not take any appreciable amount of time longer to burn when ignited with a a spark plug. Higher octane can and will help your car's performance and gas mileage.


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Explain exactly how higher octane is in any way going to affect performance on the cruze?
I had to look it up: "The octane rating of gasoline essentially tells you how much the air-fuel mixture can be compressed before it will spontaneously ignite." In a small-block turbo charged car, air-fuel mixture will get compressed beyond what a normally aspirated engine would do. With a higher octane gas, the computer can be more aggressive about trying to get more power before having to pull back to prevent pinging.
 

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I put a tank of 87 in my 2012 a week or two ago just because I didn't want to go to the cheaper 93 oct station further away, but didn't want to pay the 90c/gallon difference at the station I went to.

Holy crap. Such a difference in power delivery at low RPM. The timing pull is immediately noticeable on the early engines, especially with the plugs that do let the car pick up lower in the RPM range without knocking. Power delivery up to about 3000 RPM just felt neutered.

So far the 16 doesn't seem to care. I'd love if it ran on 87 year round.
 

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Discussion Starter · #16 ·
The Cruze was designed to run on premium. It has been confirmed multiple times before from factual data, not just anecdotal. The computer will pull timing and boost like crazy in hot weather with 87 octane to PREVENT pinging, hence the reason it's not. Higher octane gas does not take any appreciable amount of time longer to burn when ignited with a a spark plug. Higher octane can and will help your car's performance and gas mileage.


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Now THIS I can understand.
It's a computer error then, since the cylinders and engine as a whole, really don't raise a degree at all.
The cooling capabilities are spot on for the car.

I can think of 2 ways to solve it.
1- Risky: Trick the computer to change the temp sensor, to make it believe the incoming air is actually colder than it is.

2- Safe: Somehow make the incoming air cooler.

Since a decent intercooler is too expensive, all I can think of, is a way to cool the air flowing from the Turbo to the intercooler.
If that hose could be made from metal with fins on, it'll cool the air considerably!


For those who say that the stock intercooler is working well enough, it isn't.
It's obvious to me, that the car works best, and pulls most at 75F.
Anything above is degrading performance.
At 85F there's still enough performance left to ride it like normal.
At 90F there's a noticeable performance loss.
At 95F it becomes annoying
and at 100-105F you haven't got enough power to accelerate on the on-ramp of an interstate with the rest of traffic.

So if the intercooler was doing it's job, the computer won't have to need to compensate for the heat.
but it does.

Anyone has any more experience with parts that could cool the air better than the stock intercooler system, by cooling down air coming from the turbo into the intercooler?
 

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For those who say that the stock intercooler is working well enough, it isn't.
It's obvious to me, that the car works best, and pulls most at 75F.
Anything above is degrading performance.
At 85F there's still enough performance left to ride it like normal.
At 90F there's a noticeable performance loss.
At 95F it becomes annoying
and at 100-105F you haven't got enough power to accelerate on the on-ramp of an interstate with the rest of traffic.
That's because the ambient air temperature is higher. As @ChevyGuy said, the intercooler cannot cool the intake temp below the outside air temperature. A bigger intercooler, more fins, metal pipes, heat wrap, nothing will cool it below the outside air temperature. Even if you spent $1000 upgrading the intake system, you will still get better performance when the outside air temp is around 65-75.

Anyone has any more experience with parts that could cool the air better than the stock intercooler system, by cooling down air coming from the turbo into the intercooler?
You could setup a system to spray cold water onto the intercooler. Check this out.

https://www.enginebasics.com/Advanced Engine Tuning/Intercooler Sprayers.html
 

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Discussion Starter · #18 · (Edited)
Well,
I highly doubt that the intercooler cooling down the air to ambient is staying cool, when it has a Turbocharger on one end, compressing air in, making the entire cooling element heat up.
THe air coming in the engine has to be at least several tens of degrees hotter than ambient, and more so, the higher the outside temperatures become.
Delta T increases as outside temp increases.
And while I totally believe that up to 75-80F the temperature coming in the engine is pretty much hand warm, any outside temps above that, and the air coming in the car becomes hot.

I was more looking into perhaps pre-intercooler tubing that could cool down the air a bit before it enters the intercooler.
Doesn't have to be much. Perhaps 1ft of metal pipe, where a sink can be clipped or welded/soldered on.
 

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Well,
I highly doubt that the intercooler cooling down the air to ambient is staying cool, when it has a Turbocharger on one end, compressing air in, making the entire cooling element heat up.
That's actually the great thing about having an OBDII reader and the Torque app. The torque app can actually show you the air temperature at the intake and charged air temp after the intercooler. You can actually see how well it is doing. On my Cruze, there is usually about 2-3 degrees difference between the air intake and the charged air temperatures. It does go higher when I sit at a stop light, but even a larger intercooler won't fix that. But a sprayer might. I have actually considered making a sprayer a couple times. It would be nice to spray down the intercooler after sitting for a couple minutes at a light.
 
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