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Transmission cooling

Canadian_CD9A

10+ Year Contributor
807
480
Feb 10, 2012
Winnipeg, MB_Canada
I found some info that might be relevant to the DSM folks who want to do this. I was all set to use a Tilton pump & Mocal oil cooler to cool my transmission (and spray down the 3/4 cluster), but I realized that Mitsubishi did something different with their rally cars. They used a Mocal Laminova heat exchanger on the upper coolant hose to keep trans temps in check - tying trans temp to coolant temp should keep the fluid temp in a good range as long as you have a good radiator, and they’re quite efficient. Group A and WRC is about as harsh as it gets on transmissions, and this is what Ralliart did to keep it functioning. Food for thought.

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gsxitement

15+ Year Contributor
1,652
1,006
Dec 9, 2002
DOBBS FERRY, New_York
I found some info that might be relevant to the DSM folks who want to do this. I was all set to use a Tilton pump & Mocal oil cooler to cool my transmission (and spray down the 3/4 cluster), but I realized that Mitsubishi did something different with their rally cars. They used a Mocal Laminova heat exchanger on the upper coolant hose to keep trans temps in check - tying trans temp to coolant temp should keep the fluid temp in a good range as long as you have a good radiator, and they’re quite efficient. Group A and WRC is about as harsh as it gets on transmissions, and this is what Ralliart did to keep it functioning. Food for thought.

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That’s super interesting! Many water temps were insane at NJMP a couple weekends ago. Granted the high 90’s ambient temps aren’t typical, but it got to the point that even with the fans on, engine running and my blower fan blowing on the radiator, we had to start dumping bottles of water on the radiator to get the water temps to come down. But that would DEFINITELY help clean up the install a bit. Definitely an avenue to explore.
 

Canadian_CD9A

10+ Year Contributor
807
480
Feb 10, 2012
Winnipeg, MB_Canada
How would that be better than just adding an air-filled cooler?
The heat transfer coefficient is higher with a liquid than with air. This will tax the cooling system a bit more, but as long as your coolant temps never surpass 220*, your transmission will be perfectly happy. This can act as a pre-warmer for transmission fluid as your car idles, too.
 

gsxitement

15+ Year Contributor
1,652
1,006
Dec 9, 2002
DOBBS FERRY, New_York
The heat transfer coefficient is higher with a liquid than with air. This will tax the cooling system a bit more, but as long as your coolant temps never surpass 220*, your transmission will be perfectly happy. This can act as a pre-warmer for transmission fluid as your car idles, too.
Yeesh…..my coolant temps were at 250….and thats only cause that’s where the gauge stops. Working on some cooling system ducting and possibly an electric water pump.
 

Canadian_CD9A

10+ Year Contributor
807
480
Feb 10, 2012
Winnipeg, MB_Canada
Yeesh…..my coolant temps were at 250….and thats only cause that’s where the gauge stops. Working on some cooling system ducting and possibly an electric water pump.
Oof, that might even be hotter than an uncooled transmission. Is this on pump gas or E85?
 

Canadian_CD9A

10+ Year Contributor
807
480
Feb 10, 2012
Winnipeg, MB_Canada
100 octane. And only 15psi. Ambient temps were like 98°. Track temps were 130ish.
The E85 might bring your coolant temps down a bit (or even richening it up) but those conditions are abusive. I truly wonder how rally cars stay together at the Acropolis Rally, where it can get to 50*C/122*F. The stages aren’t as long, but the terrain and heat are just brutal. Racing is heat management.
 

gsxitement

15+ Year Contributor
1,652
1,006
Dec 9, 2002
DOBBS FERRY, New_York
The E85 might bring your coolant temps down a bit (or even richening it up) but those conditions are abusive. I truly wonder how rally cars stay together at the Acropolis Rally, where it can get to 50*C/122*F. The stages aren’t as long, but the terrain and heat are just brutal. Racing is heat management.
Yeah. It was insane. Not sure how the head didn’t lift or blow a head gasket. Not gonna go E85. Hard to get at the race track. And I have a couple other personal reasons LOL
 

turbosax2

Moderator
4,411
425
Nov 19, 2006
Mechanicsburg, Pennsylvania
Oof, that might even be hotter than an uncooled transmission. Is this on pump gas or E85?
Very doubtful. I see uncooled transmission temps that start to approach 300F at times. Keeping the transmission temp at coolant temps would definitely be an improvement, but I'm always wary of putting more load on the cooling system. Even with the extensive list of cooling mods that I've done, coolant temps can still approach 230F on a really hot day. This is during 20+ minute sessions, not time attack, so take that into account as well.
 

gsxitement

15+ Year Contributor
1,652
1,006
Dec 9, 2002
DOBBS FERRY, New_York
Very doubtful. I see uncooled transmission temps that start to approach 300F at times. Keeping the transmission temp at coolant temps would definitely be an improvement, but I'm always wary of putting more load on the cooling system. Even with the extensive list of cooling mods that I've done, coolant temps can still approach 230F on a really hot day. This is during 20+ minute sessions, not time attack, so take that into account as well.
When we were at gridlife NJMP, it was insane. My CEL comes on at 234°. It would come on and I would know I had two hot laps to get it done. Mind you, it would come on during my second lap. Out lap, half way through the first hot lap the light would come on, the end of that lap water temp gauge was pegged at 250 and oil temp was rapidly approaching that. One more lap…maybe 2 if I’m close to a decent lap time. Like I said….how the car didn’t blow a head gasket or lift the head I’ll never know.
 

turbosax2

Moderator
4,411
425
Nov 19, 2006
Mechanicsburg, Pennsylvania
When we were at gridlife NJMP, it was insane. My CEL comes on at 234°. It would come on and I would know I had two hot laps to get it done. Mind you, it would come on during my second lap. Out lap, half way through the first hot lap the light would come on, the end of that lap water temp gauge was pegged at 250 and oil temp was rapidly approaching that. One more lap…maybe 2 if I’m close to a decent lap time. Like I said….how the car didn’t blow a head gasket or lift the head I’ll never know.
You're braver than I am LOL I have the CEL at 225F then two other warnings on the RaceCapture, the final of which is around 235* I think. And that's when I definitely let out no matter what.
 

gsxitement

15+ Year Contributor
1,652
1,006
Dec 9, 2002
DOBBS FERRY, New_York
You're braver than I am LOL I have the CEL at 225F then two other warnings on the RaceCapture, the final of which is around 235* I think. And that's when I definitely let out no matter what.
We were pouring water on the radiator with the fans on, engine idling and my big blower blowing on it. That was the only was to get it to cool down. Taking it all apart this off season, so we’ll see how everything looks
 
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