josephsc

I was at a track yesterday and encountered a new problem -- not enough engine cooling. My temperature was high enough to give me the ! warning. Strangely enough, just two weeks ago, the same car did double duty (running in two groups with two drivers) and gave zero trouble. My car have never given me this problem before, but I managed to temporary solve the problem by running cabin heater all the way up.

And then, I was just watching the news and figured out why my car was running unusually hot. It's because it's friggin' hot outside -- record-breaking temporature hot! 105 deg F at Thunderhill (man... how do guys in AZ handle this all the time?) The worst part is I'm going back in two days and it's supposed to be even hotter!

I'd really like to increase my engine cooling over the weekend when I don't have access to any parts suppliers except the local ones. I was feeling heat-stroked on the drive back (full cabin heat wasn't helping) -- and would like to avoid that.

I'll clean the radiator off of rubber and insect parts it picked up, but what else? What are some steps I can take that actually help? What would just be a waste of time?

* I'm currrently running 50/50 distilled water/coolant -- should I go to 80/20 or 100/0? Water wetter?
* Burping the radiator: just do the easy way with the bleeder bolt, or use a pressure radiator tester?
* Should I take off the thermostat at the water pump?
* Should I run without a bumper? That won't duct more air to the radiator, but directly towards the engine...

luckett

Well, actually it did hit the temp light at the track when we double stinted it. At the same time, the brakes were fading so I backed it off for a couple of laps and the temps came down. I believe I mentioned it to you, but maybe it was overshadowed by the drama of smoke pouring off the brakes.


Are you using a 968 radiator? I've never had a cooling problem with mine (well, except for that little heater control valve incident).

Is the space bewteen the bottom of the radiator and bumper sealed?

A splitter would help the cooling as would a big hole in the hood just behind the radiator or anything that creates a low pressure area to evacuate the air from behind the radiator. You could put a small lip on the bottom of the radiator.

The fan actually blocks some of the air flow thru the radiator, but you would have to pay close attention to cool down.

I'd go with some water wetter. Pure actually water transfers heat better than an antifreeze mix.

GlenL

Pure water plus wetter would be most efficient.
Just do it the easy way.

No!

No.

Make sure the radiator and condensor (in there?) are clean and the fans are working right.

If you've got aftermarket chips they'll advance the spark. This makes it run hotter. In that case you might consider going back to stock.

Better oil can help with this as well. Maybe go with Amsoil TRO2000 or other high-end synthetic.

josephsc

Thanks guys! I have my 'todo' list for this weekend now.

Chris, I didn't realize I was already running a little hot then. But yesterday, I was consistently running hot -- every session including the first one, unless I turned the cabin heat all the way up. And it's supposed to be 8 degrees hotter on Monday....

I hadn't thought about the radiator airflow and back pressure -- I think I might be able to tighten a couple of panels in there. BTW, it's a 951 radiator in there.

Hmmm... I didn't think about the oil -- makes sense though. I'm currently running Mobil One synthetic. Is that good enough -- or is Amsoil significantly better?

josephsc

One more thought:

I want the front of the radiator exposed as much as possible, right? Would cutting out the section of the spoiler between the foglamps help deliver more air to the radiator? Would that have any negative effects (aside from aesthetics)?

I also have an aluminum splashpan that goes behind the plastic one. This is the one that mounts behind the oilpan. I'm not sure if that would help with the back pressure since it's at the end of the engine bay...

GlenL

I think it does, and I've heard the same from others. Never have done a comparable test, though. You might give it a whirl. I am sure that the Amsoil 20w50 racing oil (aka TRO2000) gives better high engine temp oil pressure.