CHJ In Virginia

Last weekend I was running a NASA event at VIR. The ambient temps were 95 Deg + and the car was running coolant temps in the 220-230 Deg range and oil temps in the 265 range at the end of a session. The car seemed to be down on power a bit due to the heat. I decided to take advantage of the on site Dyno facility at Viper Engine and Drivetrain lab on Saturday afternoon. The dyno graph of the 4 pulls is below.



Cooling and the temp of the engine coolant played a major factor in the power production. The car has complete factory stock intake, engine, exhaust and programming. I am running a DRM exterior oil cooler. The first three runs were performed with coolant temps between 225 and 230 Deg. This was to simulate the actual track conditions of the day. Best HP was 351.1 and TQ was 330.1. Cooling off the temps to 205 on the 4th pull produced a substantial increase in HP and TQ. Max rear wheel HP 366.6 and max TQ of 350.2. Increases of 16.5HP and 20.1 TQ !!!
I know what my next mod will be a Ron Davis, Dewitts or other dual row aluminum radiator. Who has experience with the aftermarket radiator units and whose do you recommend ?

flycastinguy

I recently installed a Ron Davis in my C5Z and have run 3 events since. Coolant temps have been in the 200-210 range and oil temps in the 225-230 range. Seeing this, my instructor at CMP said "gotta love those Ron Davis radiators." Good luck.

Bob

John Shiels

before I set my car up properly with coolers from DRM I could see it going flat after 10 minutes of running hard. I have said this many times before here.

Rob's 73

At about 230 the ECU will add fuel and pull timing. On top of that, at 98 degree intake air temp the ECU will also pull timing.

OCCOMSRAZOR

I use the LG Supercool Radiator with the oil cooler. I ran at an event last Thursday in 102 degree heat. Track temps were above 120 degrees. The highest coolant temp I saw all day was 207 and oil temp was 247.

I run distilled water and water wetter and have no air conditioning condensor in front of the radiator so your results may vary.

But, it's a damn good radiator.

0Randy@DRM

We have seen some of the same results on our dyno. It's just the way it is. The ECU does most of it, but even with all that tuned out, your results are going to be about the same.

We use Ron Davis radiators all the time, fit, finish and cooling have been great!!!

Randy

mgarfias

Ron Davis all the way. Those things are works of art, and work really well too.

AU N EGL

If your running with that much heat, would mixing some 100 octane help? say 4:1 93:100 or 50:50 ?

Rob's 73

The only way it will help with power is if you tune for it (i.e., don't let the ECU pull the timing or add the extra fuel). The octane will help prevent detonation as it is.

wtknght1

Most of us in T1 use the Ron Davis and it is very good. I think any good aftermarket version with a high capacity will work very well. There are several you can get though with different features...such as an integrated oil cooler...integrated tranny cooler, etc, etc. Don't forget about the tranny and diff!!!

Running down here in the south (100 degs, 100% humidity), I just don't think you can get enough cooling.

0Randy@DRM

We suggest using a tick of race gas in just about everything at the track. With the heat, long pulls over and over, the rpm and pounding the crap out it. It just is a little safety at the end of the day. A few gallons of race gas per tank, is one of the cheapest things about a track day. Pump gas is crap and sometimes you get a bad tank of it.

Randy

0Randy@DRM

I'm sorry

AU N EGL

That is what I thought and what I have been doing. about 4:1 93:100 octane

fej

Do you think that cooling off the oil/coolant temps also allowed the intake temps to drop enough to let the computer throw some more timing back in? The stock tune starts pulling timing at around 85* if I remember right, and the reduced underhood temps may have brought the intake air temp down enough to contribute to those gains.

Don't get me wrong, I think lower operating temps will help make power, just wondering with a stock tune if the air temp was not a factor as well.

Thanks for the info
Fej

Rob's 73

factory 03 Z06 tune pulls 1 degree at 98, 2 degrees at 104, 3 degrees at 113, 5 degrees at 122. My IATs with a Blackwing and vented hood run about 3 degrees higher than ambient.

Another thing that can rob power is if you trip CAT Over Temp. You can then command an afr as rich as 11.7 to 1.

fej

I thought my 01 pulled earlier than that, but you are probably right Rob, thanks for the clarification

Fej