On 2G DSMs, there is a restrictor mounted on a spring in the slave cylinder that keeps the clutch from disengaging too quickly. This isn't a problem until you try to launch the car. Instead of having a clutch that grabs, the clutch just slips badly when you let the clutch out quickly. It is there to keep the the driveline from getting too much of a shock. But the stock clutch doesn't grab well enough to give it a bad shock anyway.

I was browsing the Evo parts database program when I came across the same exact restrictor on the Evo. This could account for some of the premature clutch deaths in Evos.

Here is how to remove it. There is a hydraulic line that travels from the master cylinder to the slave cylinder. A banjo bolt attaches this line to the slave cylinder. Remove the banjo bolt (probably a 14mm head). Once you do this, fluid will start to come out of the line. So try to cap it by shoving a large vacuum cap through the line. Be careful because brake fluid WILL eat paint!

It looks as if both the brake master cylinder and clutch master cylinder are fed by the same reservoir. If it starts to get low, fill it back up with some good quality brake fluid. I like valvoline synthetic.

Now for the actual mod. Use a magnet or a wire to remove the spring and restrictor from the hole in the slave cylinder left by the removal of the banjo bolt. Now bolt everything back together.

You will have to bleed the slave cylinder once again. But if you kept the reservoir full, the brake system should be fine (even if you didn't, the brake system would still be fine because of how the lines attach to the reservoir).

Here is a detailed description of the removal on a 2G DSM:
http://www.jumptronix.com/2g_go_fast...emoval_faq.htm

 

Interesting post. I would hazzard to guess, based on posted 60' launch times, that clutch slippage resulting from hard launches has not been a real issue with the EVO. Some owners have purposefully been slipping the clutch in order to maintain revs and not bog when launching. This technique, while effective, is known to cause excessive clutch wear and premature failure.

 

Thanks for the investigation and post - was wondering if we had this restriction.

Wonder if the clutch cylinder restriction has any thing with the reported problems with fast shifts - i.e. perhaps it slows disengagement or ??? Anyone hear about this issue affecting shifting on DSMs or WRX?

Also, seems like clutch engages pretty close to floor (because it is new I suppose) and this may effect fast shifts. Clutch is no doubt self-adjusting.

 

Really? My clutch engagement point is very high up off the floor on my car, and took some getting used to compared to my 95 Talon AWD which grabs an inch off the floorboard. I've heard that high engagement points lead to quicker clutch wear since the disc may not be fully engaged when the pedal is lifted. Any other EVO owners have a high clutch pedal engagement?

 

I too had a Talon (95 TSi AWD), and that clutch grabbed very close to the floor. My Evo's clutch grabs pretty high up. Almost too high for my liking. My Integra R grabs right in the middle, which I feel is good, but it's just personal preference.

I think I'm going to try this mod to see if it does make the clutch grab quicker. Kinda tired of smelling clutch on launches.

 

This is the valve in question:

 

Same here FWIW. Clutch enagement on the EVO is so high as to be annoying. I'm betting that does contribute to premature failure. I'm not touch

 

Same here FWIW. Clutch enagement on the EVO is so high as to be annoying. The Talon and Eclipse...right off the floor. I'm sure this is adjustable as it was on the DSMs, but I don't feel like crawling under the dash on this car. If Mitsu wants it that high, then so be it. If it fails, it's gonna fail well before the warranty period ends and I'll get a new one out of the deal. They'll learn eventually.

Oh, on topic stuff... This mod has been done for years on the DSMs. It's been so damn long since I did it on mine, I don't remember the results. I'd love to hear what someone who currently has grinding high rev 1-2 shifts on the EVO notices after doing this mod...

Thomas Dorris

 

The WRX does not have a restrictor.

Like others have said, my old DSM (95 eagle talon AWD) had a very low clutch engagement point.

 

I am going to adjust it lower myself since Mitsu will probably say it's a wear item and you just abused it causing it to wear prematurely. I'm not so sure you will get it covered unless you can prove otherwise.

 

I like where it grabs. My svt contour was real high also loved it guess I just got use to it.

 

Yeah, Bill, your clutch was just abnormally high. I just kept letting it out and giving it gas and thinking, "why aren't we moving yet?" It would be difficult going from a Talon to an Evo with a clutch like that.

Thanks for letting me take a drive, though. I had a blast!

 

The 2003s do
VV

 

If the clutch is engaging "too" high it may not be gripping %100......

Sounds like a problem waiting to happen. Clutch should be no higher then 3/4 to the top.

 

really?