Oil Cooling Dilemma - Opinions Needed...

[IROC]

This is one of those situations where I know what the right thing to do is, but can't seem to make a decision...

My '76 has a 3.2 in it. Back when it had the stock 2.7, I installed the standard Mocal radiator-style cooler kit in the fender (with a fan) to replace the trombone cooler. It worked great - even on the track. The Mocal cooler just can't keep the 3.2 cool enough on the track (works fine on the street), so a couple of years ago I bought a larger Setrab cooler (a "150") and all the hoses and brackets to install in the same location as the Mocal.

I never got around to installing the Setrab but now that I am ready, I have decided that the best route would be to install it in the front bumper opening (IROC bumper) rather than the fender location. I talked to Chuck at Elephant and plan to get the hoses, etc. to make this work, but in reality the larger 172 cooler would be better if I'm going to go with the front bumper location.

So...am I wasting time using the 150 in the front bumper? Does anyone want a full kit to mount the 150 in the fender location (brand-new-in-the-box)? Should I just mount it in the fender as intended (I have all the parts to do that)?

Any insights appreciated...

[KTL]

Mike,

I think the 150 will be fine in the center mount position. The 172 is just about ideal for the IROC bumper opening from a size perspective, but the smaller footprint of the 150 still will work well. I'd be willing to bet the Mocal would be fine in the center position too. Moving the cooler to the front opening makes a huge difference in cooling effectiveness. Also be sure to bump-out (in) the chassis wall to create an effective flow path for the cooling air behind the cooler.

I run a less efficient Fluidyne large cooler in my '79's IROC bumper and it works very well. Engine never sees more than 210 even on the hottest of days. A fellow racer (cstreit) runs a small Mocal up front and his 3.3L N/A engine runs very cool, almost too cool. Both our engines are carb'd, so they can tend to run a little cooler if run on the rich side. Still, I think your 3.2 will see significant benefit from any cooler you move to the middle.

[Grady Clay]

Mike,

If the temperature issue is track only, consider the $100 Water vapor cooled 911 - the Rubbermaid Solution
You will find that this solves any cooling issue on the track.

Another simple upgrade is to change the crankshaft pulley to the 134 mm version (930 Turbo and ’78-’79 911SC) from your 127 mm version.
This turns your engine cooling fan faster and increases cooling at the source.

Reading your post, it seems prudent to install the Setrab 150 in the fender (with a fan and proper ducting).
This keeps a fender-mounted cooler so you don’t need a new bumper, etc.


What are you using for brake cooling?

Best,
Grady

[IROC]

Kevin - thanks for the real-world feedback. My feeling is that the 150 would be acceptable, but I'd hate to go through all the trouble to mount it and still be glancing nervously at the oil temp gauge on the track. Surface-area wise it is quite a bit larger than the Mocal and sealing it off in the bumper opening, etc., should really force alot of air through it. My preliminary measurements indicate that I have a decent amount of room between it and the tub...

Grady - I've previously read about the rubbermaid solution. One concern for me is the high humidity at most of the places I run. Dew points in the 70s are common. Having said that, I like the ingenious solution. I also never thought about the crank pulley change. It seems I ought to do that regardless. I have an IROC bumper now, and run 3" brake hoses from the openings to my cool-brake kit (that is a whole 'nuther issue - routing the brake hoses under/thru the a-arms...). Coincidentally, I was planning on doing a better job of routing the hoses when I had my bumper off for the cooler installation.

One thought I had that I'm sure (?) would work is to install the Setrab in the fender with a fan and then cut out my head light bucket and remove a headlight at the track. Duct everything in so all of the air from the bucket went thru the cooler. That extra airflow in addition to the fan should be fine, I would think.

[KTL]

How much room do you think you've got between the tub and rear of cooler? My Fluidyne is butted right up to the bumper opening and that leaves a couple inches behind. Previous owner notched the tub and replaced with sheetmetal to get more room behind to duct it downward. I'd like it to be ducted upward through the hood but my fuel cell and fuel plumbing locations don't allow for that right now.

The headlight modification is indeed an effective one too. Not a bad choice to go with, aside from a bit more work in tighter confines to seal it off for good forced ducting thru the cooler.

Yeah the brake hose routing is a compromise. Between the wiggly path of the hose and the obstruction caused by clamshelling a tube onto the A-arm brace rod, it's not an ideal plumbing job. But it does work. I know the 3 in. size is the standard to go with. But I found 2-1/2 is still fairly effective and gives you a bit more clearance between the A-arm and tub, where it's easy to smush the hose. We've found the key is to not restrain the hose and clamshell tube in that location. Let it float freely so it doesn't get smushed on suspension compression.

[BK911]

I had a 28 row fender mounted oil cooler installed. With the headlight removed and sheet metal ducting to force air across the cooler, I was seeing oil temps >220 on the track. Now with a front bumper mounted oil cooler, my oil temp barely reached ~190 at Barber last week in 95F ambient.

[Grady Clay]

Originally Posted by IROC

….
One concern for me is the high humidity at most of the places I run. Dew points in the 70s are common. Having said that, I like the ingenious solution.
….

Mike,

Ambient humidity is not an issue because of the high temperatures as the air (and water vapor/mist) pass through the engine cooling fins.
I addressed that question in the link.

For $100, try it. You will be impressed.

Best,
Grady