Oil temps and autoxing

[Porsche virgin]

Let me start out here: Yes I did a search.

My car runs at nice normal temps on the road, but when I'm autocrossing, it seems to run too hot. It makes sense, I drive really hard and then just come to a complete stop and let the car bake. But the other day, it was only in the mid-70s. I'm a bit concerned about autocrossing when the temps rise into the 90s, as they certainly will here in lovely NYC. For reference, I have used someone else's picture. My car was somewhere between the yellow and red lines.

Any thoughts? Is the temp OK, and I'm just being paranoid? Should I leave the motor running between runs? Should I open the engine cover between runs? Should I spray water on the trombone oil cooler to try to further cool the oil?

I'm going to get a CHT gauge, just to keep track of temps soon.

Thanks.

[bigbrotherjohn]

Opening the engine cover might help as should spraying water on the oil cooler. You could ice your intake too for a few extra horsepower, haha. Do you ever autocross with NASA Northeast? I went last sunday and there were no porsches there except for me and my father's. There will be another NASA NE autocross in july at the PNC and another at giants stadium. PM me for more info if you want, i should be bringing my 912.

[edward993]

AutoX taxes oil cooling because it's high-rev work and you never get enough speed to shed much heat. Thus, I would find "between yellow and red" normal as this translates to maybe 210-220 degrees. But I would, indeed, worry for hotter days. The trombone just doesn't offer enough cooling for the street (in hot climates), let alone for a track event ...IMHO.

Edward

[Emission]

With a trombone, you need air movement (the car needs to be moving) for best cooling effect. An Auto-X really doesn't get the right type of air (constant high speed) over your cooler.

Your "RED" line is still below my panic point of 250 F. (which is about where the highest white line is).

My suggestions:

Idle for a minute or two after your run.
Open the decklid between runs.
Run synthetic oil (better high heat protection)

If you are really freaked, you can always switch to a better cooler and an electric fan.

[Chuck Moreland]

Between the red and yellow is about 200 F, about perfect. Nothing to worry about at this point.

Remember, you temp is regulated by a thermostat. At 200 F, the thermostat may not even be fully open. When ambient temps reach 90, you may not see much increase in temp.

Note too that Autocross is of such short duration (typically about 60 sec runs) that it does not tax the oil cooling system very much. Drive like that on the track for 20+ minutes and it's a whole different story.

Do continue to monitor your oil temps and come back for more info should the temps rise significantly above present levels.

[Porsche virgin]

Thanks for the quick responses. I'll keep an eye on it, and I promise not to freak out until it hits 120 deg C.

bigbrotherjohn, I usually race with PCA-NNJR and SCCA-NNJR.

[edward993]

Hmmm, 60-sec runs, eh? Makes sense that you won't get be getting the car too hot then.
(...I've done an AutoX exactly once and we got 20-minute runs!)

Edward

[vash]

a 20 minute AX run?? dd-damn! that is alot of friggen cones.

[HarryD]

My car, which does not have an external cooler always spikes up at AutoX. I never see much above 220 so I do not worry. Once the car is warm, I shut her down between runs as there is not much cooling for my gal below 3000 rpm.

Relax and enjoy the ride!

[cary]

You need to tinker with your heater blower. I have mine converted to the old manual levers. Tossed the auto heat in the junk can.
After an ax run I lift the lid and run the heater blower with the engine off. It seems to keep the engine from heat sinking.
It likes having the air blowing over the fins.

Works for me. I've axed at up to 100 degrees.

[Porsche virgin]

Funny. I turned on the heat, too, thinking that it would at least get pull the heat away from the exhaust while I was sitting in place. It is the first thing I do when a water-pumper gets hot. I had my engine running, though. I'll turn it off, but leave the blower running next time.

Does anybody think that the Heetsheets work? I've read the reviews here, and there is no consensus. My question is, how well do they work when you are sitting still, like in traffic. It seems to me that they would at least divert some of the heat away from the engine.

[cary]

Run it for a little bit just to flush the air through with the BIGGER engine fan. I usually leave mine running for about 2 minutes.

Not real technical, but works for me.