So I decided to dig into this oil cooler topic a little more. I popped the hood after a spirited drive, and I could feel heat radiating on my face. I looked around. It wasn't coming off the exhaust (which I have well insulated), or the valve cover....... You guessed it. The trans was cooking. I can barely hold my hand on it.
Now remember, the trans robs 15-18% of the power through friction. Friction create heat. the friction heat generated from 15% of 230bhp is gonna be quite a bit more extreme than 15% of 140bhp.
So, I guess the next step is to install a temp gauge. And like I mentioned, the MZ0 I just installed has a 3rd plug about halfway up the case, kind of like a fill limit on conventional manuals. That would be a great location for a temp sensor.
But the bigger project ahead will be an actual oil cooler. I am not suggesting that I'd get a GReddy anything, but I'm posting a link as an example of what a kit looks like.
Greddy Oil Cooler Kit 2g DSM - Modern Automotive Performance
I'm starting to think that the excessive heat is very likely the cause of my 4-6 month lifespan on these M32s.