You know what? I bet the clucth issue is a very simple miscaculation on Mitsu behalf, and would be almost impossible to prove.

I bet the step height was off on a batch of these cars. IF it is off by millimeters, the clutch will die VERY FAST, and may not fully disengauge fully when you shift (SOUUND FAMILIAR?!?!?!?!?) or never fully engauge so you are always slipping in some form.

I broke mine in perfectly and my car didn't even see boost until 2000 Miles on the car. The cutch does indeed need to be broken in properly, especially on these cars, not like a truck of fart wagon. You can tel when the clutch needs to grab, took me two weeks, cuz I had a LOT of Highway driving....

 

I wish it were that simple. There is no step on the EVO so it kind of hard to screw it up. In testing the pressure plate, even if the pressure plate of flywheel was off by 1mm which is about .040" (a lot) then the pressure plate has lots of clamp load and lots of working range left. Release has nothing to do with step either. Hydraulics self adjust for whatever position the pressure plate is in. This is why release doesn't change as the clutch wears (until it gets really bad).

I believe it's possibly a combination of things. Let's review:

Pressure plate and disc = Tests adequate for power and has good design and materials. Clutch size is 240mm which should be alright.

Restrictor = slows down clutch engagement to prevent transmission damage. It burns clutch instead. Transmissions are under warranty. Clutch isn't.

AWD = Very little tire spin, harder on clutch.

Hydraulic line = Long rubber line designed to reduce negative feedback (vibration) to driver's foot. Also reduces positive feedback making it difficult to modulate clutch consistently.

Stock flywheel = Pretty light (about 14lbs) for spunky feel. As a result this makes the car harder to launch. More clutch slip required. Not really thick which makes it harder to absorb heat.

Gearing = Possibly geared too high in first for us spirited drivers. Requires more clutch slippage.

Wear limiter on pressure plate = Stops are built into the pressure plate to allow only a certain amount of wear. Once the disc wears to this point, the clutch is done. Most other clutches keep wearing until you are out of the pressure plate's working range or down to the rivets of the disc. Normally a clutch gets worse and worse until this point. Not the case with the EVO. Clutch feels fine one day and slips like crazy a couple days later.

Driving habits = Many people buy the EVO to go out and race it, whether it's down the street or on track. How can you resist that urge to plant your foot to the floor and feel the force plant you in the seat? Many Ricky Racers (sorry to anyone named Ricky) don't have a clue how to drive and not break parts (or burn clutches). It sure doesn't take a whole lot of time to burn up a clutch, any clutch, if you do it right.

Nuf said. Sorry to get windy again. Bad habit.

 

Here is a few picks of my clutch master stage 3. The disc is made by exedy and is a Steel backed Segmented Carbon/Kevlar material. It is being installed by the dealer.

 

Flip!

 

Disc closeup. If you look close you can see the Exedy logo on top.

 

ACTman,
This pressure plate looks very similar to yours. Do you know if it has the same clamping force or what the clamping force is. I guess Clutch Masters uses Exedy parts to make there pressure plates too.

 

yeah i agree the 1st gear in this car definantly leaves something to be desired for launching at least.

it is tall enough to be of use in some auto-x corners tho... vs lugging the crap out of it in 2nd... but if they changed 2nd haha..

yeah i just bring the rpms to where i want them... keeping throttle where it needs to be to keep them steady, then roll on the power quickly as i let out the clutch... i get to full power well before the clutch is totally out... the rest is just controlling how much you slip the clutch without overheating it and frying it.


just a quick question for actman... does leaving the car running between runs help ventilate / cool down teh clutch or does it make very little difference?? at some small auto-x's you can almost runs in fast enough that the clutch seems to start build up heat.

one thing a lot of people are gonna notice i think is even if they put in a great big grabby clutch, (assuming tranny& driveline is strong) dropping the new clutch isn't gonna do much else then just cause it to bog... especially with the light flywheel and sticky tires. time to practice those launches :-p

it took me about a clutch back when i was 17 to learn how to launch my first awd. i used to be into the street race scene too which is gHeY!!

 

Just got home from the track last night. Im at 2200 miles. The clutch is totally gone. I am going to take it in to mistu this week. I can only hope for the best.

 

It's got our name, it's balanced, ACT packaging and is SFI Certified...yup it's ours. It must be the one we made for Johnson at Ultimate Racing in Canada, correct? I can see evidence of some work we did on it for testing.

Exedy is the only manufacturer of pressure plates for the EVO.
Aftermarket companies (stock or performance) use them to avoid the estimated $200,000 or more in tooling cost. Exedy also has a patent on the release bearing design.

 

I don't really think it matters much since there is nowhere for the heat to ventilate to. The heat basically soaks into the flywheel and pressure plate. Now it would be a different story if the belhousing was ventilated and had a fan to push air through it.

 

Oh sorry,
I mean this pressure plate and your yellow one pictured above.

 

Dirk-

Say some guy pulled his restricter, swapped to the stainless line, and never "launched" his Evo. Also, say this guy has good stop technique for redlights- foot off the clutch and car out of gear with brake depressed, never leaving the clutch engaged unless he is shifting. But maybe he does road race and play around on the street from a roll sometimes. Will quick shifts at WOT cause excessive wear if he lets out of the gas 100%, puts the clutch to the floor while upshifting and release the clutch when the shift is complete? Is there any hope of him drag racing his Evo safely with the restricter pulled and SS line installed?

Sorry for the long explanation there, but I am wondering what a good way to prolong clutch life and still have fun with the car? Over the past few years, "this guy" has been much more damaging on his synchros and trannies (only lost one of those) than his clutches (he's never killed a clutch in 15 years), probably because of driving style.

Any advice you can offer from your professional opinion is GREATLY APPRECIATED!!

Sincerely,
Seth

PS: The tall first gear and the light flywheel thoughts are very interesting. They certainly make a lot of sense.

PPS: The only trouble "this guy" has seen out of his clutch/tranny/driveline in his Evo, is an upshift grind on the 1-2 upshift if he is hurrying the shifter a bit too much. He only did it twice and felt really bad about it.

 

Simply put, the clutch only wears and gets hot or damaged when it slips. It doesn't matter how much power or rpm the clutch sees once it is engaged (unless the clutch cannot hold the power). You can shift fast or slow but if the clutch is allowed to engage completely before seeing high load (accel or decel) it will last for a long time. The only problem with that thought is that the job of a clutch is to slip in order to make smooth shifts and take offs. The trick is to not let it see too much load during that slip time and keep the slip time brief. For the clutch's sake, the more load (power) the clutch see, the quicker you want the slip time to be, but the harder it becomes on other parts. Of course this is the reason Mitsu. uses a restrictor. Make sense?

 

Yeah, it's a Mazda disc. Personally, I don't like how wimpy the springs are compared to the EVO disc but the EVO discs are more expensive and availability is limited to Mitsu. right now.

 

Well the clutch in mine started is road to EVO heaven about 3 weeks ago and on Sunday packed it in!!
EVO VII with 24000KM on the clock............thats just not right! Its a F-up I tell you.