Better cooling for oil cooler

[cmcfaul]

I have a small Mocal radiator oil cooler mounted in the front fender. I have heard that with the right shrouding it will work better (force more air through it).

Can someone tell me or show me how it should be "correctly" installed to get the max amount of air through it.

I basically took the loop out and put the Mocal in.

Thanks,

Chris
73 911 E

[Vincent Hill]

Look at the design of the stock Factory cooler. Also consider mounting a fan you can turn on and off in traffic or when you have the AC on.

[ossiblue]

If your car is the 73 E in your signature and you still have the battery box, you will be hard pressed to fabricate a decent shroud and it will be virtually impossible to put a fan on the cooler. What you might aim for is a deflector of some sort that deflects air from under the battery box to the gap facing the cooler. I have a cooler in my 73.5 with a 2.7S engine that is a bit smaller than the factory carrera cooler and the fit is snug between the wheel and battery box but there is a space between the cooler and box. I've not had any overheating problems to date, but I don't track the car and have yet to get stuck in mid-summer SoCal freeway gridlock.

[DRACO A5OG]

If you do put a front fan, consider placing piece of ABS plastic to seal the bottom so the air can be isolated to the cooler and not just blow straight down. Plastic can be bolted on using the two housing bolts on the bottom of cooler mount.

[cmcfaul]

the battery box is there. I think there is room to fit a fan but would like to first explore natural air flow options. The only time I need more cooling is on the track. I think if I seal the bottom and sides air will be forced through it. Does that sound right?

Chris

73 911 E

[prebordao]

I also replaced the loop with a Mocal, but only some months later did put a shroud on.
Basically I sealed the bottom between cooler, body and bumper with a piece of Coroplast cut to measure. Coroplast is an extruded rigid plastic that is very light and easy to cut (however near as strong as abs, but I think is enough).
The hot weather is only now starting, but I already noticed some improvement when pushing hard, since puting the shroud.
Mind, for heavy traffic only a fan will help...

[cmcfaul]

I am going to go to Home Depot and see what I can find the will work. I will start with sealing the bottom as prebordao recommended. Someone else had said the same thing.

Chris

73 911 E

[Grady Clay]

Chris,

If your issue is track-only, consider the Rubbermaid Solution.
This is easy, temporary, inexpensive (<$100) and VERY effective.

Another is to change the crankshaft pulley-to-fan pulley ratio.
Your 911E has a 1.3:1 ratio.
There are various parts that can increase the ratio to as much as 1.83:1 as the ’75-> 930 Turbo and others.

For your cooler, with the Mocal is there room for the Factory protection plate and seal?
In spite of its restrictive appearance, it improves the air flow through the cooler fins.

Be sure the fins on your cooler are absolutely clean.

What front bumper do you have?
If you don’t have the ‘S’ bumper, you can remove the fog lights or covers to improve air flow.

Find a damaged RF turn signal assembly (with wires) and lens.
Cut it apart and make an air ‘scoop’ while retaining a turn signal.
You can temporarily install it for events.

Best,
Grady

[cmcfaul]

Hey Grady, You crack me up with the rubbermaid solution. You have been pitching that for a long time. I have actually been considering it for years. It might not be as effective here in VA where humidity is so high.

I do have the S bumper but don't want to do anything to distract from the stock appearance.

There is plenty of room for anything. The cooler has at least 3 inches of clearance everywhere. It is about half the size of the Carrera cooler so even with the stock shroud it will need significant fabrication.

Chris

73 911 E

[prebordao]

My cooler is bigger (44 rows), so it fills most of the available area. Also, I added one of the air scoops that pelican sells. Here, in europe, its legal, as it replaces a rubber strip and not the turn signal.

[cmcfaul]

This is what I have. It's the 19 Row.

Chris

73 911 E

[BK911]

On my '73.5 mostly-track car I cut out the battery box and the back of the light housing, and fab'd up some sheet metal to force the air across the oil cooler. On the street with the headlight in place, only the air from the horn grille blows across the oil cooler. But on the track with the headlight removed, a LOT of air blows across the cooler.

On my '71 street car, I am leaving the battery box in, but I am cutting out about half of the front of it, most of the back of it, and making a plenum to force all the air from the horn grill across the oil cooler.

Every little bit helps!

[cmcfaul]

My father raced this car extensively at Bridgehampton and Lime Rock in the 70's and 80's, in the highest class, with no fender cooler or any other mods at all. Made it 100k + miles before the first rebuild. I did it once and temps were north of 260. He must have done it 50 times with no ill effects at all. when asked his reply is that it's a Porsche and that is what it's designed to do.

I just completed a rebuld because of a burned piston that is partly the result of high temps (and higher compression) so I don't want to repeat. In retrospect I wonder how he did it.

Chris
736 911 E

[Grady Clay]

Originally Posted by cmcfaul

Hey Grady, You crack me up with the rubbermaid solution. You have been pitching that for a long time. I have actually been considering it for years. It might not be as effective here in VA where humidity is so high.
Chris 73 911 E

The Rubbermaid Solution is not particularly ambient humidity dependent.
Yes, it works better in a high desert.
Because the temperatures are so high across the engine fins (compared to ambient), all the water changes phase.
That is where the heat absorption occurs. Study that thread.

Try it.
You will like it.
No more "north of 260" and burned pistons (detonation?)

If nothing else, you will have a spare VDO washer pump.


Best,
Grady

[Vincent Hill]

Originally Posted by cmcfaul

My father raced this car extensively at Bridgehampton and Lime Rock in the 70's and 80's, in the highest class, with no fender cooler or any other mods at all. Made it 100k + miles before the first rebuild. I did it once and temps were north of 260. He must have done it 50 times with no ill effects at all. when asked his reply is that it's a Porsche and that is what it's designed to do.

I just completed a rebuld because of a burned piston that is partly the result of high temps (and higher compression) so I don't want to repeat. In retrospect I wonder how he did it.

Chris
736 911 E

Remember, He was using Leaded Gasoline and the Ethyl Corporation raised the Octane. SO the Fuel did not burn as Hot and everything had some protection and last, He was Smarter than you (I know that I am still trying to catch up with some of the things my dad did and still figure out how he did it??

Short story is in the 50's he drove Kaisers and every year on his way from Ohio to New York to go to school (NYU and My Mom Columbia) he would get pulled over on the PA Turnpike for driving over 120 MPH! The last time I remember seeing all of the steam coming out of the 55 ford Police car that pulled him over!. My question still is, WHERE Can you go that fast in a car of that period and still stay on the road? I have driven from Ohio to Breezewood many times and still do not see many places where I want to do that even in the Porsche!

[prebordao]

[midnight911]

my solution...that worked...