Really you are not adjusting the hydraulics, you are adjusting how soon the pedal engages the hydraulics. The pedal has an adjustable rod that pushes on the master cylinder piston. The adjustment is simply changing the freeplay from the rod to the piston.

 

The theory that the restricter causes premature wear makes sense... but I had removed my restricter valve at my first oil change, right at 800 miles on the car.

The clutch still croaked before 4500 miles. Like most the disk still had lots of meat on it, but it was glazed as were the pressure plate and flywheel.

 

I am looking at this from strictly a design point of view. I don't won a EVO (but I will take donations). In calculating torque capacity of the clutch it rates at around 350 ftlbs. The car only makes about 278 according to the ads. That extra 25% should be enough to hold even when it gets glazed or worn a bit so the natural conclusion I come up with is the restictor. Some cars only have a 10-15% reserve in clutch torque capacity. I have a lot of prior experience with the friction material that is used for this application and I know it's top notch stuff so I don't think you can blame the disc. Of course these torque figures are approximations based on assumed friction coefficients, etc. Basically, it is not going to be an exact number.
AWD is murder on clutches since you don't have wheel spin to dampen load. I don't think torque capacity is the issue. The clutch should hold the power. It may be how hot the clutch is getting as it is slipping. An overheated disc (one that stinks) is basically melting the material away instead of wearing it away. This makes for rapid failure.
Regarding springs, actually the torsional vibration is harder on the centers than the torque. You will notice that the spring center is designed much tougher than most V8 cars. This is because of the extreme torsional vibrations that occur in 4 cylinder and especially turbo 4 cylinder engines. Given the beefy design of the OE disc, I don't anticipate many problems with center sections.

 

Changed the clutch @ 32k on my evo 6... after a few hard launches around 30K. Before that it was fine...

The stock clutch is soft/glazes easily and seems to be geared towards easy daily driving. If you do any sort of performance driving etc... get an uprated clutch. Thats just how it is in land.

 

If the disc is still fairly thick what croaked? I think you are a little misled when it comes to glazing. Glazing is normal and beneficial to long clutch life. Proper break in actually is performing the glazing process. As one person said though the pressure plate has to have enough clamp load to conpensate. If you want I can check out your parts and test it to see what is going on.

 

2Cool do you still have the old parts, that would be sweet to actually have them test the parts (like if the clamping load is maybe off).

I understand what you mean by glazing. I guess more appropriate term would be the heat checking? It's pretty obvious that the flywheel and pressure plate have some signs of overheating. Most clutches don't look that bad after 80K miles, let alone 4500 miles.

Understand ACT that I am not trying to argue with you, I am just trying to come to the best conclusion we can about the clutch (collectively) that is possible. This helps everyone here.

 

The clutch disk is glazed. The clutch no longer workee, is broke.

As in, it slipped like a fat chick in a jello wrestling contest.

No friction, engine revved 2 or 3K up from where it was cruising on throttle depression (clutch pedal not engaged) then the car "caught up" with it after a few seconds. Acted like a serious stall convertor in an auto car.

Now, whether this was due to the glazing, or if it was due to the pressure plate giving up, idunno. Same effect. Clutch broke.

And yes, I still have all three pieces, saved em in the Exedy box. Nothing wrong with the flywheel that resurfacing won't fix, and I may have a use for it later.

 

I think we got the point.

 

I could make a clutch look that bad in about 5 minutes if you want. Actually, I made one look a lot worse in 6 seconds doing material testing on a dyno, but that's another story. Like you said, it's a matter of heat. BTW, I take no offense to your comments even if you were arguing with me. I love the dialog especially when it comes to clutch tech. because there are so many misconceptions out there.

 

I will resurface and rebalance the flywheel if you send the parts to me. How's that for a deal? Sorry, this is not an open invitation for everyone who has a burnt clutch. For a clutch to have that much slippage either the pressure plate is real low on clamp load, the disc was super hot at the time, or super thin, or the pedal adjustment was preloading the hydraulics.

 

If it is not worth it to you 2cool, I'll chip in for shipping so he ACT can see this clutch and let us know his results.

 

Works for me, just email or PM me an address to send it off to. I am curious as well what exactly caused the failure.

 

what are the advantages of taking out the clutch resritctor?... i hvae about 9000 miles on my car and it is starting to slip... doesnt removing the clutch restricter void warranty also if im not mistaken... wat the hell does it actually do also??? im going to need a clutch soon also... and i damn sure aint goin to get anohter one from mitsu...MAYBE thats y mistu said only stock clutches may be used to keep tranny warranty.... bcuz they knew people would b comin in for clutches left and right.... honestly i dont really like mitsu... i think they're all robbers... but ne wayz... im goin need a clutch soon.... and i dont really want to pay 1500 just for a clutch.. i want a stage 3 or stage 4........ but i want to b able to drive it good....

 

one comment, one question.
IMO people with modified cars shouldnt be responding/voting to this thread since it seems that were all attempting to figure out if mitsus clucth is ****. so, it doesnt make sense to voice opinions on the clutch if you have changed the vehicle perf. specs.

Attention SCCA people....would an aftermarket clutch affect the class that you would have to run in??

 

Question for ACT:

Does it make sense for a tranny leak to cause all of my tranny fluid to leak out and cause my clutch to burn out and to ruin my tranny? This is what Mitsu told me. But the replaced both under warranty. If this is true then i would appreciate an explanation!