Track whores with MRs?
Jan 29, 2008, 08:24 PM
#721
A few years ago when I first started rebuilding the 6 speed transmissions I had an opportunity to speak with an engineer at Mitsubishi about the 6 speed. They are well aware of the skepticism that surrounds the 6 speed but that doesn’t change the fact that the transmission is rated for 290ft.lbs of torque. I know... I didn't like to hear that either and it would have been nice if they shared that with us, the end users who can't stop thinking about the EVO.
Jan 29, 2008, 08:54 PM
#722
A few years ago when I first started rebuilding the 6 speed transmissions I had an opportunity to speak with an engineer at Mitsubishi about the 6 speed. They are well aware of the skepticism that surrounds the 6 speed but that doesn’t change the fact that the transmission is rated for 290ft.lbs of torque. I know... I didn't like to hear that either and it would have been nice if they shared that with us, the end users who can't stop thinking about the EVO.
This rating is what the transmission can deal with for the duration of the intended service life with an OEM clutch. We can assume that the intended service life would be just far enough to get through warranty. Sure you can shove more torque through the 6 speed but the number of cycles that the transmission can withstand before the probability of failure catching up to it will be less & less. This is the S/N fatigue curve and transmissions can’t escape from it either, especially when you’re attempting something that it wasn’t designed to do.
The whole trick is knowing the bleeding edge and backing away a few steps. In the case of the 6 speed I wouldn’t want to make it take anymore than 400ft.lbs if you are looking to get the most life out of it. Think of it like revving a stock block 4G63 past 8k, sure you can do it but for how long?
Jan 30, 2008, 08:19 AM
#723
The 290ft.lbs rating is not the torque at which the thing blows up. It's much higher, I've done destructive static load testing on the 6 speed transmission and the torque numbers that I can achieve before parts fail is above 1000ft.lbs in some of the gears but it varies from gear to gear. Now understand this is where they fail immediately.
Jan 31, 2008, 11:02 AM
#730
When using 9310 and other high nickel type steels, there are problems with getting the hardness to Rockwell high enough so that the parts don't wear out and Cryogenic treatments can raise the hardness by several points. A retired engineer that does our Cyrogenic work can raise the hardness from 60 to 63RC which needs to be tempered out but what gains are found from complete conversion of austenite to martinsite is probably negligible because we are still putting enough force on the gears to yield the metal. I'm not saying the Cryogenics don't work, they do when done correctly, but the gains that I'm looking for so you guys can put twice the torque through something that wasn't designed for aren't going to be found by this process. It's still more cost effective to switch to a 5 speed if you really want to make that kind of power and have a transmission that last.
Feb 3, 2008, 12:25 PM
#732
I do not use a cooler, I do not launch the car. At least half the miles are from road course or weekend warrior on/offramp abuse i nthe northeast. I spend most of my time in 3,4,5 gears.
Sure, one day I may have a problem, but I'm going on year 3 and the only parts ever needing replacement was an A/C sensor ($40 part) and the equivalent to my harmonic balancer (odd, right?!?!).
Don't live in fear, drive smoothe and enjoy your car.
Feb 25, 2008, 04:46 AM
#734
Does the cooler prove to help reduce fatigue and keep temps down on a 380-400ish whp car? Is it worth the expense to install on a dd car that sees maybe 5-8 track events a year? Or would I just be buying minimal time if any? Also if I were to do the cooler and eventualy switched to the 5 mt, I would imagine I could just as easily still use the cooler right?
Feb 25, 2008, 07:50 AM
#735
Does the cooler prove to help reduce fatigue and keep temps down on a 380-400ish whp car? Is it worth the expense to install on a dd car that sees maybe 5-8 track events a year? Or would I just be buying minimal time if any? Also if I were to do the cooler and eventualy switched to the 5 mt, I would imagine I could just as easily still use the cooler right?