So after a number of tests using our prototype ZChip tuning tool and trying to validate the results with some quartermile runs on the dyno, the +98whp and +93wtq proved just too much for the stocker. The Evo X would drive fine, but once you heat up the disc a little bit, then launching was out of the question.



Our clutch made it to a measley 5500mi before it said "no". Now its still got 95% of its life left, however we are not interested in a unit that we cannot fully test our results with. Back on the shelf the stock unit went.

We decided to move to an ACT single disc unit we have had a lot of luck with on the Evo 8-9's. Cars proven to run 11.2-11.5's in the quartermile. Interestingly, we learned that the Evo 8-9-10 all share the same input shaft size and spline count so Evo 8-9-10 discs are interchangeable. We have not determined whether the pressure plate is interchangeable. It has a different part number, but appears to look the same with the same bolt pattern.



Anyhow we decided on the ACT HD-TTP version clutch which we have tested to 575hp or so. With our tenured experience installing, tuning, driving over 100 units here a year, we steered clear of the XT pressure plate as it most always exhibited issues in shifting and lockouts.



We retained the OEM flywheel, however two days after the install of the clutch, we received ACT flywheels in stock for Evo X. Our OEM unit was new enough to be reused and the factory flywheels are pretty lightweight as it is.



In the process of the install, as we always do, the fluid was changed in the transmission and transfercase. We opted for our usual dose of Redline Fluids and in went the heavy shockproof in the TC while we used Redline MT90 for the transmission.



Greatest news of all is that it appears that the Redline MT90 has CURED the notchy grinding shifting from the factory's inability to choose the correct fluid for the Evo X application.



So far we have about 750mi on the clutch, have test launched it about 8-10 times and its working great. We have a stockload of these units available if anyone is interested in the street version or our special HD-TTP road/race version clutch.

 

So in summary: The stock clutch can not handle the ZChip - at least in a repeated launch scenario?

 

The stock car cannot handle the stock clutch in stock form with launching.

 

Doesn't surprise me... the stock unit cannot handle repeated launches on a stock car for a long time.

Makes me wonder how the SST transmission is going to hold up to a moderately modified car.

 

Scott, this is great news! Is it possible that the new clutch assembly also contributes to smooth shifting?

My seat of the pants impression is that the stock clutch assembly is draging ever so slightly. You can feel the car move as you shift from N to 1st.

 

The factory X clutch "feels" weaker than the stock Evo 8 - 9 clutch.

Part of it might the extra 300lbs it weighs.

 

Scott, but did the stock clutch ever feel to you like it was draging a bit?

 

Nice work!

 

Excellent write up.

 

Awesome! Now the car launchs well, you should take this to the track to see how it does. With the extra 100hp, this should be able to put down an easy 110mph trap speeds! I'm dying to see what this car can do....

 

Hmmmm....

 

so this is the bone stock evo x you are testing the z-chip in.

 

Scott's Evo has no mods other then the Z-chip and an MBC.

 

This is correct.

 

I gave the stock clutch one more try Wed night, just got back from the local strip.

It was turbo weather and I pumped the tires to 45 PSI and even went through the burnout box to get the tires wet. I held the ASC down for 5 sec to get all the traction assist settings off and make my first run. All of these things should have spun the tires since it was 60 F outside.

At 24 PSI or 2 PSI lower than at the shootout on 93 pump I ran a 12.91 @ 108.59 with a 1.87 short time... I'm getting 15 psi at 6k rpm stutter and no matter how fast I release it, the torque this car is laying down just wrecks the clutch. It was spin city to 7k then in 2nd it slightly spun then climbed up. Third and fourth seemed fine for that run but when I let the car cool for the next run it barely held at all and I couldn't apply power until third gear.

These stock clutches are the worst matched piece o crap I've ever seen. Any street launch with their factory supplied 2 step has resulted in a clutch burning smell and that was when it was stock. I'm calling my friend at the dealership and see if they will cover the install if I provide the parts, it's worth a shot at least and with 3k on the clock this is just unacceptable for a performance car.