TORQUE CAPACITY
89-99 AWD DSM: The factory torque rating for the 89-99 DSM transmission is roughly 250 ft.lbs of torque.
Recommended clutch that holds around 450 ft.lbs of torque for the daily driver who street races and occasionally goes to the drag strip. Shockloading a set of gears with excess torque will severely reduce the number of cycles before the teeth fail and must be kept to a minimum.
5 speed EVO-4/9: The EVO is a production version of Mitsubishi’s famed rally car and while many people tend to think of it as the ultimate drag racer it was clearly not designed for it. The EVO 5 speed transmission is rated for 380t.lbs of torque but you still need to be careful when you dump the clutch because the strain that is placed on the drivetrain can fatigue critical parts. These parts are: 1st gear, input shaft and transfer shaft. Just don’t dump the clutch too aggressively and you’ll be fine. Also, keep in mind that more is not always better; using a clutch that is capable of holding way more torque than what need will only reduce the service life of the gearing. I recommend using a clutch that holds no more than 600 ft.lbs of torque due to the limitations of the rest of the drivetrain. Shockloading a set of gears with excess torque will severely reduce the number of cycles before the teeth fail and must be kept to a minimum.
6 speed EVO-4/9: Use caution with the 6 speed transmission that was used in the 05-06 EVO as the rated fatigue limit is just under 290 ft.lbs of torque and I find it impressive that this transmission is capable of even that. I recommend using a clutch that holds no more than 400 ft.lbs of torque if you are wanting to get the most life out of it.
TYPES OF CLUTCHES
DAILY DRIVER: OEM style clutches are best for daily drivers who are looking for the longest clutch & drivetrain life. Clutch life will vary with how you drive. The torque capacity must properly chosen so that the clutch slips before parts break. More about clutches can be found on this site later. Sprung hub type clutch discs are recommended because they reduce transmission chatter from the harmonics of the engine making their way into the transmission. These harmonics will make the transmission chatter because of the backlash between the gear teeth and will wear out the gears and splines on the input shaft as well. This is why OEM clutches use sprung hub damper assemblies. However, sprung hub assemblies are not designed to cushion the drivetrain from shock loads and the damper springs can get damaged from hard clutch dumps. This is also compounded when aftermarket clutch manufactures increase the clamp load of the spring plate without doing anything to strengthen the damper assembly. To avoid damaging the sprung hub assembly one must learn the classic slip-dump method.
ROAD RACING: Single disc puck style clutches shift the best for road racing or autocross period. Don’t even think that a twin disc can outshift a single disc when it comes to road racing unless you are willing to spend 4x’s more for a high-end racing clutch than what a well designed single disc clutch would cost. The reason for this is due to the low mass clutch disc, it reduces the amount of work the synchronizers must perform making them last longer. They can be driven on the street and offer decent service life as long as you’re not launching the balls off the car. When choosing a single disc puck style clutch, the less number of pucks the less rotational mass the disc has. Don’t get too caught up in how many p.s.i. the pressure plate has, instead be more concerned that the clutch has the proper amount of torque capacity for you application.
DRAG RACE: Carefully make your decision when choosing the torque capacity and pay attention to the torque capacity data provided as they are important when it comes to the life of your transmission, transfer case and rear differential assembly. Racing type clutches are intended for hard core racers, where all that matters is winning the race and rebuilding or replacing parts often is part of the game, not daily drivers where it needs to last tens of thousands of miles. If you drive it on the street you should consider using a full face organic clutch disc for longer service life. Puck style clutch discs can be used in a daily driver but don’t expect it to last.
RULE OF THUMB: THE CLUTCH IS SUPPOSE TO SLIP BEFORE DRIVETRAIN PARTS BREAK. IF YOU DRIVE IT ON THE STREET, USE A CLUTCH THAT IS SIMILAR TO THE ORIGINAL EQUIPMENT.
RACING TYPE CLUTCHES ARE FOR RACE CARS, NOT DAILY DRIVERS. CHOOSE YOUR CLUTCH WISELY AND REMEMBER THE MORE YOU ABUSE IT THE SOONER THEY WEAR OUT.