Z/28: improving radiator and oil cooler?

[brt3]

I'm curious if anyone else has considered a custom radiator and/or oil cooler, just to drop temps a little? I'm not overly concerned, except that I tend to run in places that often have extreme temps. Thunderhill at 104 degrees tends to stretch the outer edges of the envelope, if you know what I mean. Being new to the Camaro universe, I'm not sure -- given that this is only a thought, at the moment -- who to contact regarding a custom radiator and oil cooler.

Just wondering if anyone else is already researching this, and I'm going to head over the the Moreno Build Thread to see who they turned to for these products...

[2SSRS@Gen5diy]

how hot is your car running?

[brt3]

At Thunderhill we ran a two-day event on the new circuit. It was so hot the track began breaking up in spots, and the car peaked at 285 to 290 on oil temps and 245 on coolant temps. No warning lights, except that A/C was unavailable, but I felt like this was probably pushing things just a bit. I'd like to have just a little more cushion, if possible...

[White_SS/RS]

Did you remove the water tray under the hood extractor? The oil temp looks fine but your water is pretty high.

[brt3]

Originally Posted by White_SS/RS

Did you remove the water tray under the hood extractor? The oil temp looks fine but your water is pretty high.

Yes, I did make all the changes for track usage specified in the owner's manual...

[Zfatuated]

brt- you unintentionally swapped the temps didn't you? Should be 285-290 oil, 245 coolant?

[brt3]

Originally Posted by Zfatuated

brt- you unintentionally swapped the temps didn't you? Should be 285-290 oil, 245 coolant?

Oops; proof that when overworked I do NOT multitask well...

[McRat]

Thoughts:

The AC kill is apparently programmed to 5000 rpm stock, if I'm reading the HPTuners file right.

If I wanted to Be Cool and Run Cool, I'd try these things first:

Reprogram engine electric fans
Install 160°F thermostat
25% coolant PLUS a bottle of water wetter.

Program AC to 7100rpm cutoff, BUT program to 90% throttle cutoff.
This way, the AC runs anytime you are at part throttle, regardless of RPM.

Then, go to the bigger coolers. Bigger coolers add weight in the nose.

[brt3]

Originally Posted by McRat

Thoughts:

The AC kill is apparently programmed to 5000 rpm stock, if I'm reading the HPTuners file right.

If I wanted to Be Cool and Run Cool, I'd try these things first:

Reprogram engine electric fans
Install 160°F thermostat
25% coolant PLUS a bottle of water wetter.

Program AC to 7100rpm cutoff, BUT program to 90% throttle cutoff.
This way, the AC runs anytime you are at part throttle, regardless of RPM.

Then, go to the bigger coolers. Bigger coolers add weight in the nose.

Great points, all. Except for one thing; changing the 'stats voids the warranty. I was hoping to run one or two seasons under warranty, before starting to play with the performance by (maybe) giving Katech a call. I'm thinking about one of the Moreno crash-bars up front, so that might be balance the increased weight of the bigger coolers...

[backtotintops]

I will do the water wetter next but at 82 ambient I got oil to 292 and coolant to 243 with factory coolant mix and rain shield out in 30 min run. No warning lights.

If you do want custom..try http://www.rondavisradiators.com

[Zfatuated]

"Engine Cooling System Messages

A/C OFF DUE TO HIGH ENGINE TEMP
This message displays when the engine coolant becomes hotter than the normal operating temperature. To avoid added strain on a hot engine, the air conditioning compressor automatically turns off.
When the coolant temperature returns to normal, the air conditioning compressor turns back on. You can continue to drive the vehicle."

So programming the compressor to run regardless of engine temp is a good idea?

And I'll follow that up with a question that deeply perplexes me: if all that it required to reduce the temperature of a loaded engine operating at high rpm's was a thermostat that opened at a lower temp, why even bother with a radiator? You get my point? I am seriously not trying to be an ass but how does this suggestion keep cropping up from people who would otherwise appear to understand mechanical things? Do people clearly understand the function of the thermostat, it would seem not.

High temps when loaded (and heat dissipation capacity) are not affected by the temp at which coolant flow is "switched on". Thermostat has no effect on the capacity of the cooling system to transfer heat to the atmosphere.

Furthermore- An engine will suffer greatly accelerated wear by running it too cool! A specific engine is designed and manufactured (tolerances) to operate at a specific temperature range. It's just as risky to over cool it as under cool it. It would be great to have one of the GM engineers step in and educate us on the facts of this engine but that's not likely and in the meantime I'm sure as hell not going to think I can outsmart them (and roll the dice) by altering what they programmed into the ECU.

One of the fixes Porsche's engineers implemented to keep the new GT3 engines from blowing up was to program into the ECU an RPM restriction until the engine reached full operating temps, because too cool is bad!

To each his own but folks should be crystal clear on the big picture.

Originally Posted by McRat

Thoughts:

The AC kill is apparently programmed to 5000 rpm stock, if I'm reading the HPTuners file right.

If I wanted to Be Cool and Run Cool, I'd try these things first:

Reprogram engine electric fans
Install 160°F thermostat
25% coolant PLUS a bottle of water wetter.

Program AC to 7100rpm cutoff, BUT program to 90% throttle cutoff.
This way, the AC runs anytime you are at part throttle, regardless of RPM.

Then, go to the bigger coolers. Bigger coolers add weight in the nose.

[Zfatuated]

PS- You've got a full factory warranty right now.

Start mucking with all this stuff...and you don't.

[brt3]

Originally Posted by Zfatuated

...And I'll follow that up with a question that deeply perplexes me: if all that it required to reduce the temperature of a loaded engine operating at high rpm's was a thermostat that opened at a lower temp, why even bother with a radiator? You get my point? ... High temps when loaded (and heat dissipation capacity) are not affected by the temp at which coolant flow is "switched on". Thermostat has no effect on the capacity of the cooling system to transfer heat to the atmosphere.

An interesting (and civil) discussion. I don't know if this will add or detract, but I agree with your last two sentences above except for the idea of thermal inertia. Temperatures could continue to rise after the thermostat opened, whereas a lower switch point might result in slightly less overall temperature rise.

That said, my point is conceptual and I will let people with more experience discuss the pros and cons. I've always read about switching thermostats but have no practical experience with doing this mod...

[McRat]

Originally Posted by Zfatuated

"Engine Cooling System Messages

A/C OFF DUE TO HIGH ENGINE TEMP
This message displays when the engine coolant becomes hotter than the normal operating temperature. To avoid added strain on a hot engine, the air conditioning compressor automatically turns off.
When the coolant temperature returns to normal, the air conditioning compressor turns back on. You can continue to drive the vehicle."

So programming the compressor to run regardless of engine temp is a good idea?

And I'll follow that up with a question that deeply perplexes me: if all that it required to reduce the temperature of a loaded engine operating at high rpm's was a thermostat that opened at a lower temp, why even bother with a radiator? You get my point? I am seriously not trying to be an ass but how does this suggestion keep cropping up from people who would otherwise appear to understand mechanical things? Do people clearly understand the function of the thermostat, it would seem not.

High temps when loaded (and heat dissipation capacity) are not affected by the temp at which coolant flow is "switched on". Thermostat has no effect on the capacity of the cooling system to transfer heat to the atmosphere.

Furthermore- An engine will suffer greatly accelerated wear by running it too cool! A specific engine is designed and manufactured (tolerances) to operate at a specific temperature range. It's just as risky to over cool it as under cool it. It would be great to have one of the GM engineers step in and educate us on the facts of this engine but that's not likely and in the meantime I'm sure as hell not going to think I can outsmart them (and roll the dice) by altering what they programmed into the ECU.

One of the fixes Porsche's engineers implemented to keep the new GT3 engines from blowing up was to program into the ECU an RPM restriction until the engine reached full operating temps, because too cool is bad!

To each his own but folks should be crystal clear on the big picture.

Most all digital engines are programmed to shut off the AC at WOT or RPM, regardless of water temp. Even many of the carburator engines had an A/C switch that shut off the AC clutch at WOT.

The "Too Hot" mode is Too Hot. Not only does it shut off the AC in most digital engines, it goes into Protect Mode, limiting throttle and or timing until it drops below the recovery point (programmed). If the temp continues to climb on most GM products, it goes into Limp mode. Often this is under 50hp, just enough to get you to safety even with a dry engine.

What I am talking about has nothing to do with Protect or Limp modes. It has to do with how the AC is turned off for performance reasons.

If you want to stay cool in your car, and if in fact I'm reading the file right (I don't have my car yet), having it shut off at 5000 rpm means it's not going to be running much if any while racing. Because even when you are on the brakes, the AC is off most the time.

Now, I might have read the file wrong. I'll double check. But I'd rather leave like the other LSx engines and turn it off at WOT, not RPM.