Front Cooler air flow

[Jbabic]

I understand that airflow is everything to a heat exchanger.

I am wondering if anyone has seen a huge difference in having a front oil cooler in the fender without a hole cut out in the front spoiler and then with a hole cut out.

There appears to be enough of a gap to achieve airflow, but then again, a bigger whole may make a ton of difference

Thanks.

[APKhaos]

The 84-89 Carrera has a built in hole - where the fog light sits - so it is easy to do the test by removing the fog light.

- removing the fog light helps reduce temps
- fairing in the area between the bumper and the cooler helps a lot more by forcing all of this air through the cooler
- the combination of the fairing and a larger hole is the most effective, but try the fairing before you start cutting your valence.

You may still need to cut to get more air, but at least you have maximum effect from the airflow with the fairing. Make a simple fairing from light gauge Al. Fix it to the bottom of the valence and the oil cooler mounting bolts. I can post a pic if this will help.

[VincentVega]

There's also a notch in the bottom side of the bupper for this reason as well. I like this approach as it's not really noticable.

[APKhaos]

Chris, do the earlier cars [pre-SC] have the bumper notch? Not sure what year he has, so its hard to tell what he has at present.

[Emission]

Removing the front right fog light makes a huge difference in cooling - as long as the car is moving.

I didn't like the asymmetrical look (minus on foglight), so I bought the Pelican oil cooler air scoop. It also works very well (maybe slightly less than the removed fog lamp). I plan on making a fairing to plug the hole on the bottom to force air through the cooler. Remember, all of these only help when the car is moving!

[APKhaos]

Just to restate....the fairing alone improves cooling more than removing the foglight [alone]. The combination is best of all, and maybe the scoop is just as effective as removing the foglight. I only do this for the track, where the looks aren't as important as maximum cooling.

And yes, this gain is when moving - only. If you are overheating in traffic, the fan route is the only solution. Search the archives for Spal to find plenty of good info on after-market cooling fans.

[JMPRO]

I read somewhere that the Porsche engineers decided that the tire , turning at a high speed causes a vortex of air that turned with the tire, This caused a low pressure area behind the oil cooler and naturally the air will flow from the high in front of the cooler to the low in back of the cooler. The cooler scoop and removing the headlight provide a cooler source of air for the oil cooler because the air is collected higher off the ground where it can be several degrees cooler than what goes under the valance. I tried various kinds of ducting after i installed the cooler scoop and found no measurable differance in temps over the reduction from just the scoop alone.Some of you engineers may be able to address the vortex issue, it just made sense to me.
Jerry
By the way, i make the "Cooler Scoop" so take this with a grain of salt.

[APKhaos]

I think quite a few people on this board have seen measurably improved cooling with the fairing in place. The guy who suggested it to me has been building 911 track cars for many years. His observation was that the fairing was more effective than a second [driver's side] fender cooler in his Carrera.

Would be interesting to test the scoop vs the foglight removal. Anyone done that [aside from JMPRO who might be a pro-scooper]?

[JMPRO]

Tony, i haven't tested the difference, but i would guess you would get simular results. The fog light opening is larger but the air is being scooped up closer to the ground and is not as direct a flow as the cooler scoop. The scoop opening is small but will flow about 550 cfm at highway speeds, and not to forget the cool factor- the scoop looks neat and a hole in the valance is just that, a hole.
Jerry
I have plenty of scoops in stock, no waiting.

[jmz]

you can take the driving lights out of the bumper too.

[Adam]

This is a good thread. I'm glad I decided to go the whole hog with my cooler install...



I pick up my 911 tonight after having the Carrera Cooler fitted, with a large electric fan (one of Keith Epperley's alloy-framed, 1.8A 12v jobs), aluminium stone cover/fairing and foam seal (not pictured). I was toying with the idea of maybe getting a JMPRO scoop for next summer, but I think it'll only be necessary for track days, which I'll do later this year.



What's the general opinion? With Seine Systems Heet-Sheets, will this solve my cooling problems? We get pretty hot weather (upto 115ºF in summer)...

[Emission]

Adam,

That looks beautiful. I am confident, especially with an electric fan, you'll have plenty of cooling.

Unfortunately, my limited (third car) budget prevents me from spending more than $150 on the cooling issue. I have many other areas of the car that gladly suck funds from my pockets...

[911pcars]

Adam,
Boy, am I glad you installed the fender-mount oil cooler. HeetSheets, by themselves. won't provide the substantial effect a cooler can provide. You did the right thing with a proper oil cooler. Still, as others have suggested, airflow behind the fender is marginal, so the more you can direct to this area, the better. My first choice would be a front-mounted, in-the-bumper cooler. No fan required, oil temps. should not exceed 220ºF.

Let us know how it works out.

Sherwood Lee
http://members.rennlist.org/911pcars
www.seinesystems.com

[Adam]

Sherwood,

The highest temps I've seen have been around 220ºF as it is, but that sort of heat terrifies me in a 2.7. I fitted the HeetSheets last year and noticed that they prolonged the buildup of heat, but once hot, it wouldn't cool down at all. For short trips into town, on hot days, I could actually get where I wanted to go without the nagging worry of excessive heat. In short, they did what they advertised, and did it very well. The trombone just sucked!

I'll give you all an update on how it goes. I've also had a duct-style wind deflector fitted to the base of the cooler to direct air up from under the car to the cooler.

Thanks for the compliments!