Well, I would say I have been very easy on the clutch so far, No launches over 3000 rpm and only one or two at 3000. No clutch drops. The clutch does seem to have a tendency to lockup too slow and I have smelt it after it slipped too much... I backed out of the throttle a bit to let the clutch catch up that time.

The other day I was changing parking spots at the office and had to back up a few times and pull forward a few times, revs never got above 2500 but I smelled the clutch for sure, and so did the guy that was with me.

The thing is to get the clutch to engage without a lot of chatter and vibration it requires a fair amount of slipping, at least when the car is not warmed up. The chatter seems to have gotten worse in the last month. And the car was taken on a 100 miles drive by one of the dealer techs to make sure my stalling problem was "cured" about a month ago so I hope he didn't glaze the thing (could have been me as well but I have no idea how he drove the car so...).

I only have 2500 miles on my car. I've had plenty of cars with with performace clutches:
87 rx7 turbo with ACT
83 street ported rx7 with aluminum flywheel and racing beat clutch
90 miata with BEGI Turbo and ACT clutch
98 contour with Fidanza Flywheel and CLutch master stage 1

Of all these, the EVO is the easiest one to "smoke" the clutch and the most difficult to engage without chatter.

I have yet to remove the restrictor (I think that is the biggest culprit in the tendency to over slip) for fear of voiding my warranty, but If mitsu isn't going to warranty any more premature failures then I may as well in the hopes that I can extend the life of my cluth.....

 

Can you put up some how too's and pics maybe if you decide to remove the restrictor. Thanks.

 

After 2K miles mine feels fine but fragile: it really doesn't bite hard when the clutch is popped, instead it slips a lot, producing a horrific smell. Also, I have a friend who is an engineer and did some development work on the Evo for his company, which is a supplier to Mitsu, as part of the conversion to US specs. He says the transmission is the Evo's weak link. My theory (and it really is just that) is that to mask that problem, Mitsu went with an even weaker clutch since that would go first, is not covered by the warranty and thus would save the company the costs on the transmission, which is covered by the warranty.

 

What/where is the restrictor? I gather it is in the hydraulic path? I don't see the part mentioned anywhere in the clutch section of the FSM.

So far I have had no trouble or even smell with the clutch, but I'm probably easier on the car than most.

Dan

 

This has to be the best thread on here that I have encountered to date. ACT, thanks for taking the time to troubleshoot this. Hopefully, we get the problem solved and Mitsu does something like reward your company with a contract to replace all Evo 8 clutches with a better setup that you design. That would be great. Win/Win situation for all of us.

Great thread.

Josh

 

Clucth is already starting to slip (3100 miles) plus the clutch throw-out bearing is already going out (that was about 2500 miles)

 

Oh plus 2nd gear syncro already grinds at higher RPM shifts

 

Hey I started it.
Seriously though, ACT involvement in this thread is monumental. It's not often you see a manufacturer share information like this and try to help determine the cause. Most people just want to sell what they have that's better. This of course is no shot at the other vendors on here, I think we are all lucky to have some really good vendors on this site.

 

Where's ACT based out of, California? I wonder if they would want to use my Evo as a test bed for some prototype assemblies. I will be living across the US in Mississippi come October, but if they could work out something with somebody they know locally on the MS coast, I would volunteer my car for various projects. ACT has always been strong in the DSM community and I would love to see them continue with the progression of the 4g63 with the Evo.

Josh

 

Oh, and timzcat, thanks for getting the ball rolling. This is a strange problem that needed to be addressed. You da man!

Josh

 

Aww, thanks man.

Well I took the restrictor out today.
The difference is pretty clear, I can actually feel the engagement now as compared to before. There is a pic below.
Taking the airbox out is the cleaner way to do it cause you aren't under the car and brake fluid. I just figured I'd take the 2 bolts out and remove the slave cylinder and do it on the bench.
Bleeding the system was a *****, I was by myself. Ultimately what worked best was taking the bolts back out of the slave and putting a hose from the bleeder in a container of fluid. Then I just pushed the pushrod in and out and got all the air out real easy. Of course I did take the cylinder off so I probably introduced a lot of air.

 

What is this restrictor that everyone is talking baout and what are the potential gains for it?

 

Is that the restrictor plate??

 

There already is a how-to in the how-to section called clutch restrictor removal. ( at least i think it's in the how-to section)

 

Yes that is the restrictor and spring. You can see the flow is allowed through the hole in the center and around the outside.

To answer the othere question, the restrictor is there to slow the fluid travel back to the master cylinder from the slave cylinder.
The reson it is there is if you drop the clutch it will not engage all at once and will be slowed because of the restrictor.

I was somewhat opposed to the removal at first but now that I did it, it feels a lot better on engagement. I haven't smoked my clutch yet at 2000 miles (never smelled it) and I am hoping now that it is well broken in and the removal of the restrictor it may actually last for some time. Now I may actually run the car soon.