Pictures from weekend @ Willow Springs, too hot - questions... Options

[campbellcj]

Here's a few (kinda lame) pics of my cooler setup. Note that the shrouding at the front spans all the way between the headlight buckets, and then tapers back to the width of the cooler itself. The taper is nearly 10" IIRC so I figure this gives a bit of "ram" effect. Also I don't have a pic with the top shroud piece removed, but as mentioned before the cooler is laid-back at approx 45 ° angle. The entire trunk floor section behind and under the cooler (back side) is cut out and flared slightly.

[campbellcj]

It's hard to see in this pic (black on black) but the inlet opening goes all the way between the headlight buckets axis as well, and is approx 6-7" high, covered with a medium mesh (small enough to keep significant pebbles or large bugs out).

The spoiler factor is interesting; I hadn't thought of it but it seems logical that a tiny stock valence would allow substantially more airflow to pass under the car vs thru the cooler. I will probably go to a spoiler about 1" deeper than this one if I can find one I like.

[campbellcj]

Oops forgot the pic

[TimT]

Here is my front end set up.. I formed a piece of aluminum to the shape of the IMSA spoiler on my car. I then riveted some 3" belting to the aluminum..

With this, the air has really only two places to go.... over the car, or through the oil cooler..

With the car at rest there is two inches of clearance....My friends tell me that at speed, the rubber is almost touching the pavement.. and under braking is scrapes the pavement.

My seat of the pants report tells me this works..

[TimT]

forgot the pic

[Howard]

3 Dumb questions
Shouldn't the oil get to at least 220 to burn off water vapor and contaminants?
And isn't any decent oil sold today good to 300 or more without breakdown?
Don't modern water cooled engines today get the coolant to 240 plus in the cylinder head? My V8 does, so why would the oil be cooler?

[campbellcj]

I dunno all the answers to your great questions Howard (by any stretch), but IMHO yes it is "optimal" to get the aircooled engines to 210-230°F and hold them there. I suppose if you religiously change the oil and filter every 3K then it's not all that horrid if the car runs at 180-200 all the time, either. It's really the repeated 240+ conditions that we all should try to avoid, per most of the pro's. The -4's without auxiliary oil coolers seem to shoot up to 270-300 very quickly in hot track conditions so this is a very real issue for many of us.

Regarding the modern oils, I don't know what claims are actually made or proven by the manufacturers, but I have been led to believe that synths are "good" to 250 or above whereas dinos rapidly break down once they see 240-250 temps.

It is an interesting topic, as my Audi regularly sees 225+ oil temps, and is a turbo car as well, yet the factory oil change interval is like half a million miles or something...call me "old school" but I usually change the oil about 2-3 times as often as "required" on most of my cars.

[Howard]

The web is a dangerous thing...

Motor oil \"facts\"???

[J P Stein]

On a 911 motor, the temp sensor is located at the front of the engine....not quite at the end of it's journey thru the engine. It still has to go thru the spray bar in the cam housings and thus help cool the heads.....the hot stuff. It has already gone thru the engine oil cooler at tthe start of the journey. God knows the temps when it gets sucked up by the scavenge side of the pump.

So....the temp gauge is just an indicator, not a final or the hottest temp of the oil. Personally, I happy as a clam to see a max reading of less that 212 on the gauge....usually, it's less than 185f. That temp will not boil off water/gas, but it will still evaporate it in a hurry.

[siverson]

An update for everyone who was wondering what the result was. Took my car to the dyno a couple weeks ago, and it turns out my Autothority chip was -way- off for the modifications I had, and the car was running dangerously lean and had a strange power curve.

So, that's my best hunch as to why I had such high on track temperatures. Rather than throw more money at the Motronic with a custom chip, I decided to get this... Vrooom!

Busy with moving and work right now, but should have it put together in 3-4 weekends...

-Steve

[seanery]

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