Oil Cooler confustion

atr911 · 12-19-2003, 09:59 AM

I'm looking for a front mounted oil cooler for my 78 911. I'm putting the RUF front bumper on and removing the fender mountd cooler and putting a front mounted version in. There will eventually be a 3.6 conversion on this car so bigger is better.

A few questions that I couldn't answer through searches:

1. What size and type is the best to use for the front mounted cooler. I'd like to keep costs within reason here.

2. Can the Oil cooler be mountedd to the bumper/valence or do I have to mount it to the actual front pannel of the car. If I can help it, I'd prefer not cut and weld but if I must I can live with that.

I don't mind creative answers (aslong as it's within reason) Shoot me some advice/links/whatever you might think will be helpful!

Thanks guys!

Adam

Chuck Moreland · 10:15 AM

I always advise that you put in the largest cooler that will fit, doubly true with a 3.6. A small inexpensive cooler wont seem so cheap when you have to replace it with a larger one to get more capacity. A setrab std-172 would be a good choice.

Mount it to the tub. You don't want all that weight being supported by a fiberglass bumper. It will crack.

For the cooler to be effective, you MUST provide a good exit path for the airflow behind the cooler. The Ruf bumper has more room than most, so you may get away with mounting as far forward as possible. However that leaves cooler more prone to damage. See Thom Fitspatrick's recent curb incident that destroyed his cooler.

The better choice is to notch the front of the tub behind the cooler, providing an exit duct ala factory '73 RS style. Then you can mount the cooler against the front of the tub.

widebody911 · widebody911's Garage

Why are you removing the fender cooler? Unless you're doing a slant-nose conversion, I'd say keep it.

Some people have installed a front cooler without cutting the trunk, but you don't get much airflow thru the cooler, which is what you really need.

Plus I'm just a maniac when it comes to cutting and welding.

I'm getting ready to re-do my cooler setup; I just picked up my new C2 Turbo bumper yesterday; I'll probably get started this weekend.

Here's how I did it with an RSR bumper.

http://vintagebus.com/howto/bumper-cooler/

Wil Ferch · 12-19-2003, 10:29 AM

OK...I have ( natch) a different view on air flow over a front cooler..

Many here are strongly focusing on the amount of air-space behind the cooler. I would say that it is MORE important to seal the perimeter of whatever size cooler you're using...even wth only 1/2-1" space behind it. It's the path-of-least resistance we're worrying about, and unsealed edges have ( IMHO) more of an effect than whether you have a small or large amount of structural stand-off *behind* the cooler ( that's still important though...but shouldn't be our primary focus).
--Wil Ferch

widebody911 · widebody911's Garage

Translation: it's not how deep you go, it's how tight it is on the sides

But seriously, on my IROC bumper, I'd used weatherstripping foam on the sides to control the airflow.

Quote:

Originally posted by Wil Ferch
OK...I have ( natch) a different view on air flow over a front cooler..

Many here are strongly focusing on the amount of air-space behind the cooler. I would say that it is MORE important to seal the perimeter of whatever size cooler you're using...even wth only 1/2-1" space behind it. It's the path-of-least resistance we're worrying about, and unsealed edges have ( IMHO) more of an effect than whether you have a small or large amount of structural stand-off *behind* the cooler ( that's still important though...but shouldn't be our primary focus).
--Wil Ferch

cowtown · 10:39 AM

Quote:

Originally posted by widebody911
Some people have installed a front cooler without cutting the trunk, but you don't get much airflow thru the cooler, which is what you really need.

I have to disagree with this (on the post-74 cars, at least). With a little thought, you can get well over an inch of free space behind the cooler with an RSR or RUF-style bumper. No cutting required. My thermostat never opens all the way, and the car (930 engine) will never rise above 180 degrees unless sitting still for a while.

There are some pictures of my installation here:

RSR bumper and Center cooler done! Many pictures inside

widebody911 · widebody911's Garage

Quote:

Originally posted by cowtown
I have to disagree with this (on the post-74 cars, at least). With a little thought, you can get we

Yup, well done. Maybe I'm just a little to quick to grab the cutting tools...

Just wait until you see version 2 of my front cooler setup, bwahahahahahaha!

cowtown · 12-19-2003, 10:44 AM

Thom I used your site as a reference point when I started shopping for bumpers. Also love the spring plate calc.

Can't wait to see the next version of your bumper.

Chuck Moreland · 12-19-2003, 12:21 PM

A 1 inch rear space might be okay for a street car in Ontario. Put that same car on the track in a warm climate and you'll see how inadequate it is.

Yes, seal around the cooler. But a clean, low restriction exit path for the air will make a huge difference.

Bill Verburg · Bill Verburg's Garage

There are quite a few variations exhibited by the posters here. I used a B&B, other have used Setrab, Mocal and Ruf. It's been my experience that a single B&B sealed at the edges so all of the air goes through the cooler w/o any tub modification is fine even on 100&degF track days even w/ a 3.8RS engine. As has been mentioned the tstat never stays fully open so engine oil temps stay ~85&degC at all times.

The caveat is that in really heavy stop and go traffic on a 100&degF day a fender mount w/ fan would be a real asset.

A short while ago there was a Ruf chin spoiler/oilcooler for sale over on Rennlist, it is a really slick setup.

It's my feeling that there is very little that can effectively be done to protect these things in a front mount position except to drive carefully.
Mine from the front

Mine from below

Ruf

Wil Ferch · 12-19-2003, 01:19 PM

Thanks Bill:
That's my point...I have a strong feeling that when comparing the relative merits of both aspects...forcing *all* the air through the cooler , even with a "small" air space behind it....will likely win ( my vote) over cutting / welding a clean exit path in absence of proper sealing.

Now *both*..that's the hot (pun) ticket !!!

---Wil Ferch

Bill Verburg · Bill Verburg's Garage

Thats the concern w/ fender mounts. It is very difficult to get adequate flow to them under any circumstance. As a consequence they need to be much larger than an equivalent (in cooling capacity) front mount.

cowtown · 12-19-2003, 03:22 PM

Quote:

Originally posted by Chuck Moreland
A 1 inch rear space might be okay for a street car in Ontario. Put that same car on the track in a warm climate and you'll see how inadequate it is.

I guess it all depends on your intended use.

I'd defer to Chuck on building a race car, where too big is never big enough. But a 24" Setrab, even with a 1" gap, is a huge amount of additional cooling capacity over stock.

I have not yet had the 930 engined-car on a track, but my stock '88 Carrera with fender cooler has never overheated at several Thunderhill DEs on 95 degree days. I think the Setrab will be more than adequate for doing DEs (my intended use).

But I'm not running any enduro time trials.