ZF 6 speed
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,437
Likes: 1
From: Gainesville Fl
ZF 6 speed
i went to ZFdocs website and they have a lot of helpful information there. i am curious though about this tranny anyway. i know it isnt rated at a terribly high amount of power but how much can it take if well taken care of? what kind of rwhp? what kind of 1/4 mile ETs can it handle? i know ZFdoc can rebuild it with cryogenically frozen parts for even more strength but how much does this cost? is it worth it? he also has a shifter for it. is this better than the B&M or the hurst model available? please tell me about this tranny in high hp applications (500hp+)
Melting Slicks
Joined: Mar 2002
Posts: 3,108
Likes: 126
From: S.L.C. UT
Re: ZF 6 speed (1996man)
Mine runs 10's with a stock black tag (89-93) ZF. I have had no problems. 94-96 aren't quite as strong as the earlier ones. The early ones had straight cut gears which made them stronger but they are noisier.
Thread Starter
Melting Slicks
Joined: Dec 2001
Posts: 2,437
Likes: 1
From: Gainesville Fl
Re: ZF 6 speed (tpi 421 vette)
10.18 huh? i guess thats a testament to their strength! i wish i had a stronger one though(earlier model) does anybody know how much ZF charges to rebuild them?
Le Mans Master
Joined: Aug 1999
Posts: 7,339
Likes: 137
From: WilkesBarre PA
Re: ZF 6 speed (1996man)
Bill just gave me a price of $25-3500 for a stock rebuild. I'm only putting out 400RWTQ and just had a problem with my clutch, which messed up my 4th gear syncro.
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Drifting
Joined: Aug 2000
Posts: 1,614
Likes: 0
From: Colleyville Texas
Re: ZF 6 speed (1996man)
The ZF transmission seems to have a pretty good track record for high HP/TQ strokers and nitrous applications in the late model C4 Corvettes as well.
The rear end parts seem to be the weak link. Most guys change out to the automatic for this reason. The C5 six speed transmission seems to be better on the rear end.
On a side note, the C4 beam plates have eliminated the play and helped eliminate the pushing to the right during burnouts for my ZF. Taking out the slack, per Bill, does theoretically lessen the shock to the rear which should help breakage some. FWIW
The rear end parts seem to be the weak link. Most guys change out to the automatic for this reason. The C5 six speed transmission seems to be better on the rear end.
On a side note, the C4 beam plates have eliminated the play and helped eliminate the pushing to the right during burnouts for my ZF. Taking out the slack, per Bill, does theoretically lessen the shock to the rear which should help breakage some. FWIW
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: ZF 6 speed (Red Rocket)
I have beam plates, and they work as advertised. Amazing.
There is one other modified shifter out there... it's the factory one modified in some way.
I have the Hurst and LOVE IT.
The B&M seems very popular with drag racers and the Hurst, popular with road racers/autox/street folks.
I built up ZF will take much more punishment than an equivelent T56...
There is one other modified shifter out there... it's the factory one modified in some way.
I have the Hurst and LOVE IT.
The B&M seems very popular with drag racers and the Hurst, popular with road racers/autox/street folks.
I built up ZF will take much more punishment than an equivelent T56...
Safety Car
Joined: Apr 1999
Posts: 4,623
Likes: 2
From: Ohio
Re: ZF 6 speed (bogus)
I have Bill's modified factory ZF shifter. It's a real joy, and the way it should have been built. The effort is virtually the same as stock, but shorter and MUCH, MUCH more precise. It almost "knows" what gear you want to shift to. With all due respect to the many that have "the Ripper", there is NO comparison.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: ZF 6 speed (1996man)
The Hurst is about 120.00 (check Ebay, Chris, forum member and inventor, sells them there).
The Ripper is about 190.00...
I don't know about the others.
Oh, the ZF gears are not "straight" cut, they are helical, but the angle is very slight... the angle increased in the later models...
The Ripper is about 190.00...
I don't know about the others.
Oh, the ZF gears are not "straight" cut, they are helical, but the angle is very slight... the angle increased in the later models...
Drifting
Joined: Feb 2002
Posts: 1,952
Likes: 2
From: Little Rock Arkansas
Re: ZF 6 speed (bogus)
The ZF is as strong a manual as put in ANY production car... The "Black Tags" are stronger than the "Green Tags" but not by enough as to make a critical difference. I've gone 9.90's on a stock cryogenically treated (that's what my company does) ZF with no problems. The biggest weak spot in the ZF is the syncros. You HAVE to shift a ZF properly (that means using the clutch) in order for them to have a long life. Bill does killer work on ZF's, I've spoken with him at length about them. I would love to have his cryo business but I believe he has a company close to him that would save him shipping the components to me...
-Jeb
-Jeb
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
Re: ZF 6 speed (RichS)
Jeb Is it posible to cryo a complete/built ZF? Or do you need to do the peices as it is built? Thanks.
There are some components that are slip fit. they have to be heated and others cooled... then pressed together. so I would wonder what would happen if all the components were frozen at the same time.
Drifting
Joined: Feb 2002
Posts: 1,952
Likes: 2
From: Little Rock Arkansas
Re: ZF 6 speed (bogus)
No, as a matter of fact it does NOT have to be broken down into the component level. We routinely do complete tranny's, engines, transfer cases, and diffs. The only thing I ask is that you make sure there is NO fluid left in it; not because it negatively affects the process but because it stinks up my shop when we put it in the tempering oven.
The process itself acts as a dimensional stabilizer and we typically see less than .0005" change in clearances during the process, all of which go back to their original dimensions upon completion (and stay there!). There is no temperature variation in cryogenic processing for different alloys (and some composites); the only differentiation comes during the retempering process. Some alloys we do not retemper afterwards (low temp heat treatment- 300-350F). We've never had any issues with processing complete components.
-Jeb
The process itself acts as a dimensional stabilizer and we typically see less than .0005" change in clearances during the process, all of which go back to their original dimensions upon completion (and stay there!). There is no temperature variation in cryogenic processing for different alloys (and some composites); the only differentiation comes during the retempering process. Some alloys we do not retemper afterwards (low temp heat treatment- 300-350F). We've never had any issues with processing complete components.
-Jeb
