Looking for information on Rapid Cool oil cooler for Porsche 911

[flatsixcrazy]

Hi.
I came across this aftermarket oil cooler made by the Rapid Cool, Ca, back in the days. I'm looking for any information on the performance of this oil cooler unit and where it is mounted. Has anyone used these oil coolers on their early 911 track car before? And where was it mounted? And how'd you like or didn't like it? The box has a picture of what looks like a 1966 911 and the instructions has a template of a mounting bracket (probably) for a Porsche 911. Thanks in advance. Andy

[edmayo]

I wouldn't think it was meant for the engine, fitting sizes don't look big enough.

[Harvey Weidman]

We sold that cooler for 912s and 914s. It was a serpentine style mainly used in VWs.
(I still have one from my sand buggy) The give away is the line "Oil capacity increased to 4 quarts"
We mounted them above the transmission on 914s and behind the shroud on 912s.
The Hayden manifold style cooler sold at the same time had better cooling results....
They wouldn't work on 911s as Ed said. The dry sump requires much bigger tubing/fittings....
H

[Rob R]

I had one just like that mounted above the back window of my Baja Bug in 1980. AN 8 fittings. I thought it looked cool, in reality probably not the best placement.

[savaden]

I have a cooler like that on a thermostatically controlled branch of a full flow circuit. It is mounted vertically in the front of the rear wheel well on my 912. It adds plenty of cooling capacity, so that I have never had a problem with overheating. Since the fins are spread apart there is no need to force air through the cooler.

SV

[DG58INNM]

I had a personal experience with one of these coolers, long ago. When in college, a close friend bought a '76 911S with one of these installed. This was a very nice, one owner, low mileage car, only a few years old at the time. The owner told us it was installed by the dealership (in Austin, Tx) because the car tended to run hot (typical 2.7 thing back in the day). The car did run cool, but the car had a very strange squealing/gurgling sound at idle, which was especially loud when the car was cold. My friend drove this car for a couple of years, but didn't put many miles on it. One day it lost power, and appeared to be low on oil. He put oil in it, and started driving again. It immediately leaked and smoked, ran hot, and eventually caught fire. This was about the time he went off to law school, and he towed it out to his father in-laws farm and it sat in the barn untouched for a couple of years. Finally he called me and asked if I knew anyone interested in buying it. I bought it, not knowing what was wrong.

After I started poking around with the car, I found the engine was filled to the brim with oil. Thought it was just overfilled. Drained it. Fixed the burned wiring. Car immediately filled the case with oil and got hot. Poked around a little more. Couldn't figure it out. Pulled the motor and tore it down. Eventually, there it was, way down in the center. The oil pump housing was split on the scavenge side. The forensic autopsy determined that the RapidCool cooler was too restrictive for the high volume 911 oil system. The restriction caused extra force on the pump gears, causing the pump shaft to wear the housing, galling and binding up and cracking the housing, which of course prevented the return of oil to the tank. All that odd squealing and gurgling was oil being forced through the cooler, lines, adapter, and the bouncing of the pressure relief valve in the oil filter.

I repaired this motor, with all the correct upgrades, and fitted the factory thermostat/lines/trombone. Afterwards it was one of the nicest driving 911s I ever owned. My wife and I drove it for many years afterwards. A Cockney Brown car, which I always thought was a lovely color. Foolishly sold it about 20 years ago, and got $10K, which at the time was pretty good money for the much maligned 2.7.

The short version of this is that RapidCool cooler does not flow enough oil for the scavenge circuit and should never be used on a 911.

[platas]

What a cool story, i wonder where that car is today ?

[flatsixcrazy]

Thank you for sharing the information. Looks like I'll be saving this cooler for my 912 instead.