915 cooling help

VincentVega · 03-29-2005, 07:41 PM

I've searched and found some great info on setting up a cooler for my 915 but still have a few questions. As it sits I will be picking up a Tilton or similar pump, some braded hose a small cooler along with a gauge and sending unit for peace of mind. The cooler will be mounted to the engine lid, or possibly in the left rear fender. The remaining questions are:

-I've read about using a spray bar, where can I get one of these? Are modifications needed to the case to use one? The only thing I've found was $$$, from an RSR.

-If I dont use a spray bar what's the best location to install a return to the trans, at the r&p? at the gear sets? Or does it really matter, the cooler oil is what's important?

-What is the best way to install the pickup and return bungs? Drill and tap the case to thread on an AN fitting? What fitting? Should one be welded on? If not welded, threaded and backed up w/ a nut and locktite?

This trans it mated to a 3.6 in a car that will see ~monthly track use so I want to set it up properly and hopefully have it last for a long time. The wevo internal gate seems like a nice mod, are there other internal mod's to strengthen the box I should consider 'while I'm in there'?

Thanks for any assistance!

Chris

Jeff Alton · 03-29-2005, 08:09 PM

Good questions, I am in the same boat and look forward to the responses.

Jeff

Bill Verburg · Bill Verburg's Garage

While a spry bar is nice, there is a virtual hurricane of oil in there. If you can get the return to spray at the leading edge of the crown wheel and pinion interface that is where the most heat generating stress is.

many plumb to the existing drain, I don't like that because it makes the fittings hang low

the late euro 915s have their i/o as pictured here

early 915s as pictured here

Here's a typical electric pump install, the cooler has been removed from the circuit to facilitate removal from the car

VincentVega · 03-30-2005, 06:19 AM

Thanks Bill, good information. Do you know what fitting is used at the front of the trans in the last photo (black fitting)? I assume the box in the photo does not use an internal spray bar, correct?

Thanks again

widebody911 · widebody911's Garage

Here's mine. http://rennlight.com/howto/trans-cooler/index.html

The next time I have the engine out, I'm going to make a couple of small plumbing changes to reduce the number of fittings.

Bill Verburg · Bill Verburg's Garage

I was hoping Hayden would jump in here, no I don't know what the fittings are. Not mine

wevoid · wevoid's Garage

Good information from Bill as usual.

I will offer one subtlety regarding the cooler return oil into the leading edge of the CWP mesh area. The highest temp is immediately after the mesh on both parts, also the introduction of excess oil as the gears lead into mesh can create very high hydraulic forces, enough to reduce the life of the gears, cause surface errosion. Cool oil would be best added to the trailing side as the gears come out of mesh.

As Bill says the "Virtual Hurricane" or as I put it in my favorite term "a whirling dervish of oil mousse" kind of defeats any real effort to have an effective oil spray bar system. I used a new analogy in a discussion the other day - "like trying to piss down the drain hole while your standing under the shower." It is unlikely that the oil from a spray bar nozzle makes it to the intended target. Unlike the piston oil squirters in a 911 motor, that operate in a relatively oil free environment inside the dry sump crankcase of the motor.

However the spray bar is a good way to fully distribute cool oil to many locations - think of it more as a multi location distribution manifold, rather than a discreet oil squirting device.

In terms of the black fitting on the transmission on the photo, I suspect that is a custom made oil return fitting. To return in that position is probably intended to socket directly onto a spray bar system, as that is where the spray bar will make contact with the front cover, if that axis is extended.

On of our current 2005 projects is a 915 cooling system. It will be somewhat modular and fill as many 915 cooling requirements as possible, including a no-disassembly-required kit, that will allow a 915 cooler system to be installed with the transmission in the car. No cutting, drilling tapping or welding required.

One of the flexible options incorperated is to have a spray bar option - also installed without disassembly of the transmission - just the front cover. To do this we had to come up with a machining operation to provide the port and bolt pattern for the oil supply to the spray bar. It looks similar to the black fitting in the photo.

Jerry Woods and I compared notes and agreed on what we will share as a universal port location, size and hole pattern.

It seems that the more 3.6l/915 transplant cars built, the more demand there is for 915 cooling systems. A system like Thom's is very effective and depending on what stage of your project you are at (transmission disassembled??) probably the most straight forwards option.

Regards

Hayden

Bill Verburg · Bill Verburg's Garage

I knew Hayden could give a better reply. The 915 cooling kit sounds like a winner. I wish that it had been available a few years ago, I would stil have my(reinforced) mg case 915 w/ Guard motorsport lsd

Jeff Alton · 03-30-2005, 03:07 PM

Cool, sign me up for the WEVO 915 cooler!!

Jeff

doozer · doozer's Garage

Porsche trans inverted in GT kit with tilton system spraying at each gear and ring.

Patrick Motorsports sells the parts.

VincentVega · 03-31-2005, 08:36 PM

Great info, thanks guys. The Wevo kit sounds very interesting.

Thom- Can you tell me what fittings you used to thread into the case? Also, are they just threaded in, or threaded and bolted or... ? Also, what is the side piece with the '915' on it? I noticed that pic on your site, who makes this?

Thanks again all!