These L98's just do not like heat at all...

I could hot lap my LS1 and make consistant runs all day.

Took the IROC to the track Wednesday. The weather channel said 84 degrees before I left, and it rained really good for about 10 minutes, just before we got there, it was very humid.

I still had the 190 degree thermostat from winter installed. 'cool' was the gauge reading right below the second mark, and 'hot' was slightly above the second mark or higher. I'm guessing that mark is 190? It's between 100 and 220...

With the weather being how it was, I was expecting to only trap 95-96 mph. A friend of mine brought his stock STI and ended up running 96-98 mph, and another friend brough his stock 2001 5-speed GT and went 98mph. So I wasn't really that dissappointed when my first run of the day was a 14.2 @ 94 mph.

I made another run and made a smiliar time. The people I went with started to question me and my car ;) I told them I'd let the car cool down, and I'd make another run. So I let the car sit for about 45 minutes. The engine temp read 'cool'. Fortunately there weren't many people there, and I got right up to the lights. I knew if I waited in the staging lanes for even a few minutes, I'd be back up towards 200 degrees, and I'd have wasted the past 45 minutes letting the car cool.

I had a horrible launch but ended up running a 14.1 @ 101. Muuuch better. Nothing like gaining 7mph :)

I made another run right after that, and sure enough, I got a another 14.2 @ 94 :mad:

I let the car cool and ran a similar pass. Some orange second gen puked all over the track so I cut a 2.12 60 foot :rolleyes:

Here's the bottom line:


60 foot: 2.123 2.031
1 / 8 th: 9.09 9.075
m p h: 77.5 78.03
1 / 4 : 14.132 14.223
mph : 101.33 94.27


Questions:

Why is the car not pulling timing until past the 1/8th? My 1/8ths were all really close on every run, but my 1/4's....

The good news is, I put the 160 thermostat back in, and the car stays in the 'cool' zone even in traffic. I'll have to go back, and make sure the car runs consistant, then make some more runs and play with the tire pressures and such, and try to get a couple 13 second passes in.

Might be worth a try to unplug the AC fan controller and short across it to turn on both fans full time at the track. Keep the engine right on the thermostat temp. This is the connector at the passenger side frame on the smaller high pressure AC line.

Originally posted by tom2
Might be worth a try to unplug the AC fan controller and short across it to turn on both fans full time at the track. Keep the engine right on the thermostat temp. This is the connector at the passenger
side frame on the smaller high pressure AC line.


The fans are already set like this, and it didn't seem to matter if I had the second fan on or not.

No engine likes excessive heat. The ls1 dissipates it with that funny plastic-like intake manifold, and everybody else uses aluminum or cast iron, so it transfers the heat into the intake air. If you really want to cool it down, put a bag of ice on top of the plenum, and run a switch to the secondary fan and ground it at the track to run the fan in the staging lanes.

That TB Mod might help cool it down, maybe.

you ice on the plenum while it cooled?

I dont know much about your car but have you played with the tune at all? I have set my primary fan to turn on at 185 and off at 176 or so. Then if you get a fan switch to mirror what you set your primary fan at for the secondary fan, after that get a T-stat to match that and you should be in good shape. This is what I have done, since the lovely GM cars turn on the primary fan at 228* and the secondary fan doesn't come on until really hot, and I have had not troubles at all. Maybe hits 170* in traffic.

Mine wasn't pulling strong past the 1/8th, until I changed the Fuel pump and the valve springs, the valve springs helped the most..I was floating the valves at higher rpms and speeds..

Originally posted by onefastgta
No engine likes excessive heat. The ls1 dissipates it with that funny plastic-like intake manifold, and everybody else uses aluminum or cast iron, so it transfers the heat into the intake air. If you really want to cool it down, put a bag of ice on top of the plenum, and run a switch to the secondary fan and ground it at the track to run the fan in the staging lanes.

Actually, the aluminum block and heads of the LS1 transfer alot of heat out of the motor. The polymer intake is designed so that it doesn't transfer heat which keeps heat from the engine out of the intake charge. Does any OEM still manufacture a cast iron manifold for production vehicles? I agree with the ice on the intake though. :)