What are some good strong clutches people are using? My car is procharged and I disintegrated a 450tq clutch. I have a time constraint due to an upcoming PCS over to England (Air Force) and I have about 5 1/2 weeks. Anyone know places with good deals or military discounts? My budget is screwed now due to a last minute problem. THANKS!!!!!! I know someone can help. I need part numbers for clutch and flywheel and I have no idea what to buy. My car is a 1996 Collector Edition Lt4 Zf car.

 

Ok.. ive got lots of good advice:

You want spec stage 3+ clutch and the spec pressure plate that comes with it.

This is what I recently installed on my procharged 93. its workikng great.

Also. they include a throwout bearing that appears to be well made. not sloppy like the acdelco made in china ones.

That said, I was lucky and had a left over acdelco nos made in usa throwout bearing. im using that one and have the spec one as a spare.

You can buy the clutch kit direct from spec.

The only issue I had was the current spec pressure plate required about 11 Grams of weight taken off to balance it. thats on the high side. Spec hd attempted to balance it but their balance was incorrect. so take it to an experienced machine shop and engine builder to have it balanced before install.

Also might be a good time to get rid of the heavy . Useless dual mass flywheel. use that pos as a boat anchor. use the alum flywheel.

Now about gear noise...its not caused by the flywheel likke so many people here think. The countershft rattles front to rear on the zf and the flywheel dampens it. the dual mass does a better job dampening it vs. alum flywheel. thats why so many people here hate the alum flywheel.

Zfdoc sells a thicker main shim for the countershaft that dampens the noise. do this mod and the zf stops being noisy.

I was amazed at this mod and my alum flywheel rattle went away. totally silent. btw trimming trans countershaft with a thicker shim washer is nothing new to sportscars or unique to c4.

If you go with something difft than I recommend be sure you go sprung hub clutch if you ditch the heavy dual mass flywheel for a single mass flywheel.

Somebody out there Has a push type clutch now for c4. Itd be interesting to get experience from those people running that. I think it might be intended for stockreplacement though and not perf. But I am not sure.

Finally..do not listen to the bs that one guy out here is spewing. I believe he is trying to steer people into products that he is connected with....though he does a great job rebuildikng slave and master clutch cylinders.

Good luck and thank you for your service

 

Actually the gear chatter in the ZF has to do with the size of the gears and other aspects of the transmission's design. Without the DM flywheel power pulses from the engine cause the gears to "clack" together under light load (low RPM) and in neutral. With a SM flywheel, the lighter the flywheel the more energy that goes directly into the transmission and hence more noise. The thicker shim will help with play in the transmission during shifts and under varying loads but the rattle comes from something different.

My current set up has the lightest flywheel available couple with a fairly light centerforce clutch and it is very noisy in the above situations. Nothing to worry about as it is not detrimental to the life of the trans....the car will just sound like it has a diesel engine in it.

And before you tell me it's all in my transmission...it's a brand new "optimized" blue tag from ZFDoc....with the thicker shim. Just my .02

 

the noise rattle on mine went away when I went to the thicker shim.

To be clear: the rattle on mine was not during gear changes.

The rattle was during acceleration, esp. wot low gear or lugging it in too_high-of-a_gear.

Again, I was really surprised that the rattle went away with thicker countershaft shim and my alum flywheel

Now is it possible that your rattle is due to gears and I had a really loose countershaft that benefitted a lot from the thicker shim? Thats possible.

Mine is a reman blue tag

What about your centerforce clutch...is it sprung hub? If not that could be why youj have rattle.

I have 12 Lb alum fidanza flywheel and no rattle anymore

 

I'd suggest that since it's a car that will be "with you" for awhile and also the fact that the C4 hydraulics are of questionable manufacture these days I'd have a conversation with McLeod regarding there 1345 "release package" with maybe one of their dual disc packages. Have the conversation with "them" - their ZF replacement isn't the typical "universal" release package it's actually a bolt on to the ZF using the guide-tube retainer. There's shim packages to accommodate fit and it's a very precise piece. Their support I understand is very good. You're required to give them some exact dimensions for the initial install.

I've no "first hand" and I have a spare OE/GM for my car but I had a lengthly conversation with them regarding another build. That build ended up being an A4 vs the M6.

It's expensive but I'd think it's a "done once" and then just a normal maintenance issue.

Have your conversation with "them" not a vendor - from start to finish they'll be there to answer all questions. The 1345 is the bearing/slave and they have a package that also includes their recommended master.

 

The only problem with the mcleod twin disk and push type hydraulics is I dont believe that clutch is a sprung hub.

Violent launches and gear changes become rough on the d44 Without a sprung hub doing the job that the dual mass flywheel was doing.

Also. without a sprung hub, rattle might be worse.

All this said, I might be wrong and maybe mcleod is sprung hub.

I think spec has a twin disk setup and push type hydraulic for c4. I do think it is sprung hub or has an option so (i called them and asked i think)I think its fairly new and id feel like a true guinea pig.

 

All of the SM flywheel dual disk clutch set ups that I've seen utilized one sprung hub and one solid for the street enthusiast (I've been exposed to mostly RAM Clutches though). My centerforce is a sprung hub for the SM flywheel which you really want to avoid shock loading of the driveline.

I do like the combined TO bearing/hydraulics but generally there are a few issues installing those. First you have to increase the size of the master cylinder (even when the marketing gloss says you don't, the tech specs will call for a 3/4" bore min), second you have to do the math to properly shim the unit as that shim sets part of the compression of the overall transmission (the units that don't replace the collar do not have this problem) and third, R&R'ing the unit now requires the transmission to be removed. When I went to the single mass/centerforce combo I strongly considered this route (factoring in the cheaper conventional style clutch and the deal the companies would give on their aluminum flywheels, it would have saved me money).

In the end the amount of modification to use purely aftermarket parts (retrofitting dead reliable OEM units would be different in my mind) while locking myself into having to pull a trans if I had issues with the slave just outweighed the positives. That's not even getting into the difference in TOB travel to disengagement that also favors the pull style clutch.

Back on topic for the OP; I do really like the centerforce DF clutch but I do not believe it would do well behind a boosted car (maybe I'm wrong, you could ask them) but my biggest beef was that it kept getting pushed back on back order status for a better part of a month. In your situation you may have better luck but mine shipped a solid 3 weeks after they said it was going to be built and shipped. Just something to think about.

 

All of the SM flywheel dual disk clutch set ups that I've seen utilized one sprung hub and one solid for the street enthusiast (I've been exposed to mostly RAM Clutches though). My centerforce is a sprung hub for the SM flywheel which you really want to avoid shock loading of the driveline.

I do like the combined TO bearing/hydraulics but generally there are a few issues installing those. First you have to increase the size of the master cylinder (even when the marketing gloss says you don't, the tech specs will call for a 3/4" bore min), second you have to do the math to properly shim the unit as that shim sets part of the compression of the overall transmission (the units that don't replace the collar do not have this problem) and third, R&R'ing the unit now requires the transmission to be removed. When I went to the single mass/centerforce combo I strongly considered this route (factoring in the cheaper conventional style clutch and the deal the companies would give on their aluminum flywheels, it would have saved me money).

In the end the amount of modification to use purely aftermarket parts (retrofitting dead reliable OEM units would be different in my mind) while locking myself into having to pull a trans if I had issues with the slave just outweighed the positives. That's not even getting into the difference in TOB travel to disengagement that also favors the pull style clutch.

Back on topic for the OP; I do really like the centerforce DF clutch but I do not believe it would do well behind a boosted car (maybe I'm wrong, you could ask them) but my biggest beef was that it kept getting pushed back on back order status for a better part of a month. In your situation you may have better luck but mine shipped a solid 3 weeks after they said it was going to be built and shipped. Just something to think about.

 

Thanks for all the input so far. I really appreciate it.