Oil Cooler - Rear Trunk, How I did it. Options

[MAD914]

First off, I wanted to say a big "thanks" to everyone who takes the time to post stuff. I've solved a lot of problems by searching the site. I've mainly been lurking and working, but I thought I'd do some posting of my own to solicit some opinions before firing up the engine. Please be gentle in case I've screwed this up deluxe.

After seeing what had come before me, I wanted to mount the oil cooler so that it would have cool air from the top of the car, instead of hot air from the bottom of the car. I wanted to take advantage of the same "roof-suck" effect that theoretically draws air into the engine compartment. The downside is, I have to sacrifice the rear trunk. No big deal really - I'm not going cross-country in the car.

Anyway, here is what I came up with:



I'm using a Canton filter that's mounted in the engine compartment where the battery tray used to be:




As for the oiling system, I mounted a Setrab dual-fan cooler in the rear trunk, and I'm using a 2-quart cable-actuated Accusump. I wanted the cooler to have cool air from the top of the car instead of the hot air from under the car, so I made holes in the trunk wall to the engine compartment. I've also installed a 180-degree thermostat (the fans turn on at 190 degrees). The lines from/to the engine itself are AN-8, but the system plumbing is all AN-10 to add volume and reduce flow resistance. The canister filter is positioned so the oil enters from the side, and air is purged out the top. Likewise, the cooler fills from the bottom so air is purged out the top as the oil rises up the slope of the trunk. Check valves are installed to stop oil drain-back into the engine, and to prevent the discharge from the Accusump from going “backwards” through the cooler and filter.




Here's how I laid out the installation of the cooler:



And the rough placement:



I'm hoping this might help someone, and I'd also like to hear any words of warning from folks who know more than I do (it's a large demographic).

Thanks!

[screenguy914]

I appreciate you're thinking out of the box and expect it should work in your application.

However, I would have more doubts if the cooling bits were attached to a large displacement (+2.7 liter) flat six. Some thoughts come to mind with admittedly more experience with 911s than 914s.

- At speed, air pressure is highest at the center-front of a vehicle, less so anywhere else. Any change in air flow direction (and turbulence) diminishes air flow to the cooling equipment.

- -12 AN hose/fittings should be the minimum ID for air cooled engines, especially if long runs are employed (reduces oil pump wear). While many 911 owners use -12 hose for add-on external coolers, the factory oil cooler hard lines are closer in size to -16 hose ID. Historically, external coolers were deemed necessary on 911s once engine displacement reached 2.7 liters and/or when engine output reached the 100 HP/liter threshold.

- I think fans in the "push" mode are more effective than fans that are in a "sucking" position, but I'm open to more data regarding this. In addition, the fan housings themselves pose their own restriction to clean air flow through the cooler, esp. when the fans are OFF.

- Not sure the difference in "hot" air near ground level is that much different from air temperature 2' higher that eventually flows over the hood>roof>trunk.

Admittedly, the cooling requirements between these engines are probably different enough to render my suggestions as mere "nice-to-have" rather than mandatory features. Therefore, this is one of those FWIW thoughts.

Sherwood