Wanted: Parts & Photos of Manual Transmission Coolers

[Stan.Shaw]

I want to add a cooler for my race car transmission. I am interested in what others have done, ideally with photos and parts lists

Chassis is a stripped 80 Euro S
Transmission is a 90 GT

Any thoughts appreciated, thanks!

[Danglerb]

How about improving the airflow over the transmission case via duct or fan or both?

[Stan.Shaw]

Not sure that that would help enough. I will take the proven path on this, as others have already used coolers and I don't want to break the trans.!

[rhjames]

Stan--

I would recommend you install a cooler in the cockpit, somewhere not near you, and then run a naca duct from the right window with duct down to the cooler---something like a nascar setup. You could also go so far as to install an electric fan for extra cooling, an oil pump to make sure the oil circulates well, and a puke tank for extra oil capacity (that will aid in cooling as well).

engine oil coolers are typically installed ahead of the radiator support (with a grill opening to feed it) as they run a lot hotter than the tranny oil.

only problem with putting coolers in front of the radiator is you cut the air flow to the radiator. extra coolers need to be where the air flow is, but not restricting flow to the radiator, so your choices are limited.

---Russ

[ROG100]

Stan,
The 85 to 86 IIRC used a transmission cooler in front of the rad. Could that not be used?
Roger

[928drvr86.5]

Originally Posted by ROG100

Stan,
The 85 to 86 IIRC used a transmission cooler in front of the rad. Could that not be used?
Roger

Yes, and I just replaced mine with a C&R from 928intl because the Behr started leaking at the passenger side endtank (like they all do eventually). I could possibly offer it up cheaply, all it needs is the endtank seal replaced, which is about $100. The rad. core is in decent shape and flows freely.

[ROG100]

What I am talking about is nothing to do with the radiator.
Its a small cooler about 12" x 6" mounted at the front of the car.
I am assuming it was an addition to the cooler in place on the right side of the radiator just like the later cooler mounted in front at the top of the radiator.
Either of these coolers - heat exchangers - could be adapted to use for the manual gearbox.

Even easier, and much better, rip out the POS manual gearbox and replace it with the far more superior 4 speed auto which has all the connections for the cooling circuit in place 8>)

[rhjames]

OH Roger......

rip out a stick for a slushbox.....?????

damn that makes me cringe......


---Russ

[Fabio421]

Stan

One of the European guys have done this conversion. I believe it was Erkka. Maybe drop him a PM and ask. Please post what you learn as I was thinking about doing the same at a later date. I was under the impression that you could still buy the parts from a late model car to make the swap. The diff. cover needs to be changed to accept the pump. Then of course theres the pump, plumbing and exchanger. I was planning on mounting the exchanger in a rear wheel well with a duct going to it on my widebody. I'll see if I can dig up any info on it.

Good luck.

[Danglerb]

What sort of temperatures are we talking about?

Why is it a concern?

[Stan.Shaw]

Originally Posted by Danglerb

What sort of temperatures are we talking about?

Why is it a concern?

Don't know the temperatures, but know that stroker motor 928 racecars blow up transmissions, cooling is one way of decreasing that possibility. I anticipate 500+rwhp if I ever finish this build

Sorry, Roger I am not going to replace the manual with an automatic. Weight would be one issue, but in a race situation even the latest automatics (triptronics) are still beat my manuals in road race situations. I could envision a nice automatic GTS in my future though, not to replace my small fleet of manuals, just to complement them.

I don't see any reason to consider using stock 928 parts for the cooler as they would likely be more expensive, less available and not designed for my intended use anyways.

A few racers have done this before me, so I am just chasing what they have done already

[Fabio421]

So you don't want to use stock parts? Not even the pump and cover? Are you planning on going electric instead?

[Stan.Shaw]

Originally Posted by Fabio421

So you don't want to use stock parts? Not even the pump and cover? Are you planning on going electric instead?

I haven't investigated the stock parts, but can't imagine it would make any sense for me. There isn't much stock about my car now.... All the pumps I have seen are electric.

Edit: I missed the cover part of the question. Yes, I intend to stay with the stock cover. The simple solution is to plumb to the front fill plug and pull from the rear drain plug.

[lizard928s]

the stock little cooler on the 928 is just that, little, and brittle,

I have tried to remove a few of them, I think I got one out intact, the fittings on them always break off.

[Louie928]

Originally Posted by Danglerb

What sort of temperatures are we talking about?

Why is it a concern?

It's a concern to not break the transmission. Transmission temp measurements done on a track (Thunderhill) by a noted 928 performance guru saw 300+ degrees after a few laps. That temp expands the case and weakens it a bit. That puts the shafts further apart with more load near the tips of the teeth. The 928 tranny has bearings on each end of the shafts with no support on the center. 3rd gear is in the center and a goodly amount of torque will bend the shafts. With most of the load now on the tips of the teeth, they strip and look like a cob of eaten corn. Try to keep the tranny temp to less than 180F. Freeway driving in the summer will show about 150F with it going to 175F climbing a mountain. My cooler pump comes on at 170F. Mocal makes a good tranny oil pump. I put my cooler inside the rear bumper channel and plumbed fittings into the case, but I didn't want to alter the plugs so did it differently. I used the long narrow GT engine oil cooler for the heat exchanger. I duct cool air to the heat exchanger from low behind the right rear wheel passing around the fuel tank filler and up to the bumper channel. My motivation was to keep it hidden as much as possible and to use air as cool as I could get for the cooling. Air under the car is quite hot. Seems to work, but I wouldn't recommend anyone to do it like I did. Way too much work involved.

[Stan.Shaw]

Originally Posted by Louie928

It's a concern to not break the transmission. Transmission temp measurements done on a track (Thunderhill) by a noted 928 performance guru saw 300+ degrees after a few laps. That temp expands the case and weakens it a bit. That puts the shafts further apart with more load near the tips of the teeth. The 928 tranny has bearings on each end of the shafts with no support on the center. 3rd gear is in the center and a goodly amount of torque will bend the shafts. With most of the load now on the tips of the teeth, they strip and look like a cob of eaten corn. Try to keep the tranny temp to less than 180F.

Thanks Louie,

I like the idea of it being in the rear and routing air to it. I don't have a bumper support, but maybe I can hang it on the fuel cell support structure and route air to it from the rear quarter windows via naca ducts and some light ducting hoses.

I don't want to do anything dumb, is the detriment to doing so costly with regards to aerodynamics or reduction in down force. While my car is not necessarily well design with regard to aerodynamics, my intent with the front splitter is to improve, so I wouldn't want to duct air to a trans. cooler and make the aero significantly worse than it is.

[Louie928]

Originally Posted by Stan.Shaw

Thanks Louie,

I like the idea of it being in the rear and routing air to it. I don't have a bumper support, but maybe I can hang it on the fuel cell support structure and route air to it from the rear quarter windows via naca ducts and some light ducting hoses.

I don't want to do anything dumb, is the detriment to doing so costly with regards to aerodynamics or reduction in down force. While my car is not necessarily well design with regard to aerodynamics, my intent with the front splitter is to improve, so I wouldn't want to duct air to a trans. cooler and make the aero significantly worse than it is.

Hi Stan,
I doubt the tranny cooler will require so much air that it would upset the aerodynamics much +/-. Do you have the drawing that shows the pressure distribution of the 928? The high pressure areas and low pressure areas? Use that as a guide to where you could get intake air (high pressurea area) and where to locate the exit (low pressure area).

Louie

[Stan.Shaw]

I thought there was a drawing in the Projeck 928 book. I checked (the PDF version) and don't see it quickly. I will search the 'net.

[rhjames]

Stan-

I am still voting for the Nascar setup I described earlier.....

if you're running no windows, or at least windows down, you can use a naca duct in the passenger window, route a hose to the interior where you can mount the cooler (away from you) and then if necessary put an electric fan on one side of the cooler to make sure the temps don't get out of hand......

another thing to be looked into is trans fluids.

Synthetics will handle the heat much better than dyno oils, same way I use synthetics in my Peterbilt (I run temps as high as 300 plus on a hot Texas day with gross weights of 250,000 plus pounds.....)

Fluid thickness numbers are a concern as well- 50 wgt will not create as much heat as say, 90 wgt.....

[rhjames]

Louie--

does this mean your nizzazzzzz fenders will some with no cooler slot in them......?

--Russ