I have it and so far, I'm not very happy with it on the street. I wanted to get feedback from others also.

I wanted a "streetable" clutch that would hold my power (~800 whp/tq) and while it does hold, it's not very streetable. The engagement is all the way at the top and is maybe 1/2" from the time it starts to grab to full engagement- making it suck on the street (a lot of hills here which REALLY sucks ). The fact that there is no travel in which to "modulate" the engagement, it makes it no more than an on/off switch. It would be nice if they had the geometry between the pedal travel and pressure plate travel better for easier engagement and better street manners. Not saying I want to slip the hell out of it all the time, but it could have better engagement points if it is intended for street use.

Anyone else using it and notice the same thing? Spec has been very cool to deal with, but I kind of wish I went Tex Exo Skel after talking with others about how they engage.

 

I should add, this is in an 05 GTO, so there is no adjustable master or anything being used. I was thinking of modifying the rod from the master and the clutch pedal to change the pivot point for better engagement/less travel, but I feel the clutch should work properly in the car, not the car being made to work with the cluch.
Joe

 

Joe, are you sure you don't still have the shim in place from your previous single disc? If so then that would explain the higher release point. Let me know. Thanks,

 

Positive. The shim is on top of the old clutch on my work bench . It certainly isn't a bleeding issue either, unless I should add some air to lower the pedal lol. Thanks.
Joe

 

I have not talked with anyone else that has mentioned a high pedal. Though, the window for engagement is smaller, my personal experience with this unit lead me to think of it as very drivable and quite progressive. I realize that perception is a large part of one's perspective and this may be the difference. Where are you located? Let me know and I can make a recommednation of a dealer near by that may be able to work with you.

 

You told me that it is normal for it to grab high over the phone . I don't know what a shop will do differently, but I am in Milford, PA.

I agree it is all perception, but it certainly is not progressive. The people that have felt/watched the engagement from the point it grabs to the point it stalls just shake their heads and ask "how could you drive this?"- and we are all car guys who have used everything from stock clutches to 2900 pressure plated 4 puck solid disks on the street and they have all been easier to drive than this. There is no "feel" to the pedal, once you feel the plate start to grab, it is done and the "spring pressure" from the plate is gone. I'm really concerned with how it will be as the disks start to wear.

 

OK, I just talked to Justin over the phone and he said that it should not be grabbing this high. Ugh.. Frustrating stuff here. Maybe I'll have to take a video of where it grabs and where it stalls out at (full grab) to show you guys to make sure it isn't a perception thing.

 

TTT- anyone using this clutch???

 

I just installed a twin disk in my 02 camaro last night. I have been having some clutch slippage problems and this clutch has fixed that problem. It does however have the same engagement as you have described. It goes from disengaged to fully engaged in the last 0.5" of pedal travel. I have been measuring the finger depth on several clutches and I believe the fingers are too close to the throwout bearing. I will be making a spacer to move the transmission back about 1/8" to see if it corrects the problem. I will let you know. It will most likely be about a week before I can get it done.

 

What I dont get is why you would have such a high end clutch and not be running an adjustable master cylinder. I suggest you pick one up. That will help a lot with your engagement issues, even with the small engagement window, having the pedal engage in mid travel will make it so much more driveable.

 

yeah, I have about 1/16" clearance between the throw out bearing bottomed out and the fingers- spec says this is normal, seems too tight to me?

Let me know how this works for you, I was just going to get the throw out bearing machined down a bit and give that a shot.
Joe

 

In my case, an adjustable slave is not available for the GTO. Also- I can thread mine, but it will lower my pedal height since my master is "returned" fully and it is what stops the pedal on the top end- the pedal does not hit the bump stop, it is all in the master. If I shorten the rod, it will just bring the pedal down, not change the piston position in the master.

I am going to see what happens if I give it more of an air gap between the tob and clutch fingers, if that does not help, I may modify my pedal and master cylinder pushrod to give it a better engagement.
Joe

 

Hmm well interesting. I just installed a tex exocel twin disc. I just just got the car going with it literally an hour or so ago. Quick review. ...well lets see ,it goes into gears like butter no complaints with that. Pedal pressure is firm but liveable would not call it light. And again this is at 20miles on the clutch. It makes a metallic whirring noise when clutch is pushed in..kind of neat and don't really bother me.
Chatter and engagement. It seems to be engaging think around half way or so up. It engages hard and it will chatter or grab pretty badly. I stalled it and had some big chatter and jerkiness and no way in heck would try to break in this clutch in heavy traffic or on hills today. I will try to put a few hundred on it in semideserted parts of town and do lots of starts and stops and that type of thing.I drove it a bit and cooled it down a few heat cycles. I got on the car a bit to 6000 but can't see that hurting it. won't be getting on it much though until 500 miles is on there I think. I also think you have to be meaner to the clutch after some break in stuff to take out the chatter on these clutches. and things have to adjust. I hate adjustable master crap.I blame that crap on taking out my cartech clutch. The modified stock master would not hold setting and let the clutch slip and drag until it destroyed it. And in only a few thousand miles. And it didn't smell when it was doing this being metallic type. So didn't really know it was doing it.
I like the tex uses stock hydraulics. One less thing to mess and for me thats a good thing.
So right now I am not totally happy with my tex twin for street use either and wondering maybe should have just got the tex single. But hoping it gets better fairly fast and of course I will also get used to it. But right now it does feel pretty on /off to me also. And for guys that said no chatter from the get go on the tex twin..well not sure why I got quite a bit. I have only 3.42 gears also not 3.73 or 4.10., HIgher gears help and thinking of getting some 3.73 likely when get new rear end.

So good luck on you twin disc. Some twins are supposed to be street twins some more pure race. Mcleod street twin comes to mind. But then again mcleod uses the adjustable masters.

 

First off I am not trying to bash SPEC but I have never had one of their clutches (ones that can hold serious power) that I have been happy with they all seem to be very "grabby" and hard to drive like a normal clutch. I switched to a street twin from McLeod and love it. The clutch drives absolutely fantastic and can hold whatever I have to throw at it (Dart based stroker sbf w/ twins). I hope you can get your setup to work. Good luck but if it doesn't look at the McLeod product.

 

I have to admit, I was very nervous about spending that much money with a company that seems to have such a hit or miss reputation, but after speaking with Jeremy, I felt comfortable about it. I can't say I "regret" getting it since it does grab and hold my power very well, just could have been better IMHO as far as the engagement goes. After hearing how the Tex ExoSkel is working for a couple of friends, I do kind of wish I went that route, but this isn't bad enough for me to want to just yank it out and lose $1400. I'll deal for now.

Does anyone know what the gap is *supposed* to be according to GM specs between the throw out bearing and pressure plate fingers? I thought it was supposed to be 1/8", 1/16 sounds awfully tight and leaves very little room for clutch wear.
Joe

 

I have made and installed a 3/16" spacer plater between the transmission and the bellhousing. The slave cylinder was basically touching the fingers of the pressure plate when it was bottomed out. This moved the slave cylinder back 3/16" and gives me some clearance. (could have machined the throwout bearing as well) As the clutch wears the fingers move closer to the slave cylinder and without any clearance the clutch will start to slip before it it worn out. The spacer made little difference to the point on the pedal where the engagement occurs. It still engages quickly (last 0.5" or so) but as it is breaking in it is chattering less. I have about 150 miles on the car and the clutch engagement is continuing to get smoother. The clutch has a nice firm engagement when shifting and handles the power without any problems. Overall I am very pleased with it's performance.

 

I have about 500 miles on my spec twin. It to engages at the top as described in this thread, but holds like a mother. My first issues would be it squeals at release on take offs. Second the throw out bearing knocks like hell when car is first started. I to would like for the clutch to release a little sooner, but I can deal w/ it where it is. I'm most concerned about the throw out bearing knocking. Good luck to all. Would like to here from the Spec rep. if you come across this.

 

I just put in a Spec super twin with the carbon graphite disks...LOTS of chatter and a high pedal as stated earlier, I hope it gets better, i only have about 80 miles on it so far...

 

I haven't checked this thread in a while. I just saw this post. 3/16" sounds like a lot, but if it was releasing fine, you'll be ok with it. How is it doing now that you have more time on it? My clutch started to slip in 4th the other night on the highway with around 4k miles on it. I have a feeling my "less than 1/16" air gap" that spec said was "fine" is gone and it is riding the fingers now. Gonna pull the trans and see about either a spacer or machining my slave down. This sucks. It is always the same "never heard of that before" story too from Spec.

I know Jeremy (spec01) is trying to help, but I had concerns about the clutch being so tight from day one and was told it was ok. If my disks are worn due to slipping from too tight of an air gap, I'm the one who has to pay for new disks because they'll pull the "it's not the clutches fault, it's the cars"- when I called them from day one with concerns about the gap being too tight and was told it was ok.

It seems that 99% of Spec issues I see are air gap related- too loose and people have shifting problems, too tight and the clutches slip prematurely. While a lot/all of this can be blamed on variances from car- Spec needs to at least put a note in the instructions that air gap measurement is critical for proper clutch operation and must be between .xxx and .xxx for proper clutch operation instead of making people think they can just bolt it in and go, then blame the car when there is a problem like they are known to do.
Joe

 

a standard single disc stg 5 would have been a better fit for your application.


you can't expect a clutch for these applications to work like a stocker does with lots of middle ground in the travel.

I am using a twin disc on my new build... haven't driven it yet but don't expect it to be much different from my old stg 5, which was very streetable. I got used to the on/off switch.