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Transmission cooling

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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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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.
 
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.
 
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.
 
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?
 
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.
 
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
 
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.
 
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.
 
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.
 
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
 
Installing a water mister system onto the rad and intercooler will increase evaporative cooling and could be boost or throttle % triggered.
If running a trans oil cooler set up, is there anything to consider for the amount of gear oil to add? Check valve help?
 
Here's my setup I put together over the winter:
  • TRE welded 1/2" NPT fittings on the transmission
  • Setrab 50-619-7612 cooler
  • Marco UP3 164-020-12 pump
  • Mocal AF8_240 filter (240 micron)
  • XRP -8 ProPLUS PTFE hose/fittings
  • Controlled by RaceCapture output based on trans temperature reading, currently set to turn pump on at 180F and off at 160F
  • 3D printed ducts/filter mounts/hose separators/spacers, etc.
  • I now used 3.5 quarts of transmission fluid
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I drove the car at Mid-Ohio this past weekend. The ambient temperature was only in the upper 70's but the cooler did great. This is a chart of all my sessions lumped together and you can see that the temperature got up to 180F, the pump would kick on, temps dropped immediately, and then either continued to drop until the pump turned off at 160F or maintained mid 160's for the whole session. We'll see what it does on a much hotter day but I'm pretty confident it will keep the temps under 200F and probably close to 180F sustained.
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The only problem I had is something at the top is weeping fluid while on the track. I wasn't able to reproduce it on the street, so I'm suspecting it's either something to do with sustained high speeds or RPM's and too much flow from the pump going on - not sure yet. After every session, the front of the transmission would be slightly wet from the leaking. Not enough to stop me from running, but definitely something I need to figure out.
 
Looks awesome!

What material did you go with for the 3D printed parts? I've been making functional parts from CF PETG and I see that's outside the engine bay but I'd still be worried about warpage where it touches the heat exchanger. Sooooo Nylon?

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I can't help but notice the "polygons" on your rounded edges. Can I guess that you are exporting your model as an .stl? Fun fact they don't have the resolution for curves and turn them into a bunch of short straight lines. Export and slice as a .step instead and they will come out mint.

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Looks awesome!

What material did you go with for the 3D printed parts? I've been making functional parts from CF PETG and I see that's outside the engine bay but I'd still be worried about warpage where it touches the heat exchanger. Sooooo Nylon?

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I can't help but notice the "polygons" on your rounded edges. Can I guess that you are exporting your model as an .stl? Fun fact they don't have the resolution for curves and turn them into a bunch of short straight lines. Export and slice as a .step instead and they will come out mint.

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Thanks! I use ASA for most of my functional parts and everything on this project. I'm kind of new to 3d printing so we'll see how it holds up over time. I do have high temp foam/rubber trim on the ducts where they meet the cooler, so the plastic doesn't directly touch it anywhere.

I use 3mf's for my models. I didn't realize the default settings from SolidWorks to exporting to 3mf's were lower when I did this, so that's why it came out with the polygons visible. I since have tweaked that, but I didn't feel like reprinting the ducts since they were a PITA. I'll play around with steps in the future, thanks!
 
OOoo nice. I've got a roll of ASA I haven't opened to play with yet. Also some PC that I'm scared to even try. 🙃 Great idea on the foam from an insulation and sealing standpoint. I should have realized that.

I'm on Inventor and it has an option under "Print" to 3D print but that always defaults to .stl so I just export it as a generic .step. I learned that trick from a Youtuber so just paying it forward. I'm super excited to explore more 3D printed solutions for the Galant.
 
RB Racing 03-1040 pump, MT-90 fluid and the filter I haven't decided what micron size to use yet.

Transmission is a DSM AWD with an EVO I 2.571 1st, 1.60 2nd, stock ratio 1.115 3rd and 0.833 4th. 2nd, 3rd and 4th I converted to double syncro and 5th gear is an EVO III 0.617.

Electric Oil Feed and Scavenge Pumps
Wow, where did you find the Evo 3 5th gear?
 
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