High IAT2 temps and KR

Tim Moland

Well-Known Member
Hello fellow turbo cars....
I have a lnf turbo with an upgraded Z54 turbo installed. The car makes great power, and it's pretty fast. However, I am suffering from high IAT2 temps and Knock Retard. My tuner has said he thinks the high IAT2 temps is the cause of the knock, which in turn causes the engine computer to cut timing. I'm seeing up to 8 degrees KR under full boost. My tuner wants to only see up to 2 degrees and only momentarily. I'm seeing up to 130 IAT2 temps. Keep in mind, this is with 45-50 degree ancient temps. So my temps are around 80 degrees higher then ambient.
I have the front mount heat exchanger with NACA ducts(no fans) and the stock DF intercooler. I have switched to a high flow zzp intercooler pump and have done my best to eliminate all air in the intercooler system.
Is the stock DF intercooler /heat exchanger not up to the task? I'm thinking about mounting another heat exchanger in the engine bay area below the coolant overflow and having a fan in that one. It will add more volume, and it will cool more too, especially when sitting still. Then I'm thinking the intercooler is marginal for the power im making. But I'm having a hard time finding a intercooler that has a straight through design like the stock one, but bigger. Also, I'm on 91 octane. 93 and E85 are hard to come by here.
Have you guys had any of these issues, or is my car "unique"? I did not have hptuners with the stock turbo, so I don't know if I had this issue with the stock Ko4 turbo. I'm willing to spending money to fix this problem, I just need to know where to spend it.
 

Ross

Goblin Guru
I moved my cooler closer to the intercooler, and up into the fresh air. I don't know if the front is too restrictive, but I was worried that two 3" holes wouldn't provide enough air to the cooler. Plus the clear line allows me to see small air bubbles moving when the pump turns on.
20616
 

Tim Moland

Well-Known Member
I moved my cooler closer to the intercooler, and up into the fresh air. I don't know if the front is too restrictive, but I was worried that two 3" holes wouldn't provide enough air to the cooler. Plus the clear line allows me to see small air bubbles moving when the pump turns on.
View attachment 20616
And how are your IAT2 temps when under full boost?
 

Ross

Goblin Guru
Well the supercharger doesn't heat up the air as much as your turbo can. I haven't had any problems with KR or high IATs.
The supercharger can barely make the water warm.
 

Justin

Active Member
I think your problem is the intercooler. I believe its only rated for around 350 hp and since you have the z54 I'm guessing you are right around that. I upgraded my heat exchanger to alot larger one with a fan and my iat2 usually runs about 15 degrees above ambient but sometimes up to 30 degrees above if I am driving it hard for awhile. I have the zfr 6758 so it's the same size turbo you are running. Frozen boost has a type 10 intercooler that is rated for up to 600hp. It's the same shape as the stock one only larger. I think that the one I will be switching to, looks like it will work with minimal modifications to mounting bracket. Here is my heat exchanger, I still need to add a side scoop like some others have done here but I am hoping that a larger intercooler will solve my issue
20190817_161606.jpg
20190817_161002.jpg
 

Justin

Active Member
The core is 4 1/2" thick and its basically 12"×12". In order to fit it where I did i had to move my fuel tank over about 2 inches
 

ctuinstra

Goblin Guru
This is the setup on our first car. We have since lowered it and angled it. This setup worked great! Typically only 20 degrees above ambient, your not going to get much better than that unless you ice the water to bring it below ambient temp. I need to take new photos of the current setup.

Your situation reminded me much of my tuning experience on the dyno. My tuner only put a fan on the front of the car when the heat exchanger was clearly sitting on top of the engine right in his face the whole time. After about an hour of pulls, he could not figure out why he was getting a terrible knocking sound. I kept mentioning that the HE was getting way too hot but he didn't think so. I finally insisted that he put a fan on it and let the car cool down. The IATs were around 150! I was around 150 degrees myself at this point. Once the small fan was put on and it cooled down, the IATs where right where they should be and the tuning continued. So yes, the high IATs will cause a lot of issues and it's very bad for the engine.

All you can do is keep the water as cool as possible. Ours is never warm, the water is dang near at ambient all the time. Keep good flow. Beyond that, you would have to mod the intercooler or go to ice. We are using Water Wetter with water, no coolant. It's supposed to help with better surface adhesion or something. Not sure if it's just snake oil or not. Don't really notice any difference. Just no need to run coolant/antifreeze, this car will never see either temp extreme.



20624
 

Tinkles

Well-Known Member
Well the supercharger doesn't heat up the air as much as your turbo can. I haven't had any problems with KR or high IATs.
The supercharger can barely make the water warm.
Actually it is the opposite. Superchargers create more heat than turbos just by their design, besides the vortec/procharger style.

130* is not that hot. Supercharged Ecotecs will see up to 150* or more IATs temps. I do not agree with your tuner and honestly do not believe the IATs are the reason for the high KR(from my experience with boosted ecotecs). My 1st thought is too much timing advance for the boost level and fuel. 2nd is the AFR is too lean. I would like to know what your AFRs and timing advance is at WOT.
 

JERMzSS

Well-Known Member
I think your problem is the intercooler. I believe its only rated for around 350 hp and since you have the z54 I'm guessing you are right around that. I upgraded my heat exchanger to alot larger one with a fan and my iat2 usually runs about 15 degrees above ambient but sometimes up to 30 degrees above if I am driving it hard for awhile. I have the zfr 6758 so it's the same size turbo you are running. Frozen boost has a type 10 intercooler that is rated for up to 600hp. It's the same shape as the stock one only larger. I think that the one I will be switching to, looks like it will work with minimal modifications to mounting bracket. Here is my heat exchanger, I still need to add a side scoop like some others have done here but I am hoping that a larger intercooler will solve my issue View attachment 20619View attachment 20620
Where did you get this exchanger?
 

Wes

Active Member
I think the biggest problem with the front air/water setup is the two pipes passing through the center tunnel together will exchange a lot of heat and really heat soak on a dyno.
 

Tim Moland

Well-Known Member
This intercooler instead of the stock one.
It core is 202.5 cu.in instead of 110 cu.in. but you will have to find a few extra inches to fit it in.
Justin, you are running a much bigger Derale cooler too. Do you know what size that one is?
This!! I have looked on frozen boost several times and never ran across this intercooler. This might be the answer. Along with an extra fan cooled heat exchanger. Can't go wrong with 2 right? Extra cooling... Extra capacity.
 

Ross

Goblin Guru
Actually it is the opposite. Superchargers create more heat than turbos just by their design, besides the vortec/procharger style.
...
That is news to me. I tried to find out more info using google, but it is hard to find. I was thinking that his turbo would make more heat because turbo cars generally make higher boost numbers than the 12 PSI that my supercharger makes.

I did find one guys opinion saying the opposite:
"Also, if you just look at the case of a turbocharger vs. a supercharger in isolation the Lysholm supercharger is a more efficient compressor for equivalent power inputs than a traditional turbocharger because of thermal efficiency and the fact that it is a positive displacement pump. "
 
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