TAREK

I've heard that the limit of the 928 AT is 600 hp....and that the Corvette 6spd tranny is too big to fit in place of the 928 5 spd

BUT... is this also true for the 928 AT? Has anyone looked into possibly fitting a Z06 tranny in a 928 AT chassis?

Thanks!

hacker-pschorr

If you fold down the back seats I'm sure it will fit in there.

TAREK

ha! I could probably put it on top of the roof rack too!!!

no seriously, I do wonder how much chassis modification is involved to fit the 6 spd in there

TAREK

even with chassis modification?

DFWX

I join in the inquiry. What options are there for beefing up (stronger) the 928 tranny in serious terms - for which the only seemingly not geometrically costly option might be the Z06 transmission. For racers things such as cutting out the floorboards, moving chassis structure etc is just a necessity if required for the level of power.
Other than "too big", would a Z06 transmission (AT or manual) fit up without radical drivetrain interfacing problems?
OR any other transmission alternatives?
Mark

Tony

Spend your time, $$$ and energy to get 600HP first IMHO.
That alone will be a long enough and $$$ journey.

DFWX

I do not see 600+ rwhp as a particular challenge in my project and already have 80+% of components (ie $$ spent) for this. The challenge is holding it all together - the greatest challenge being the transmission/differential.
The front engine, rear transmission is so very rare that there are little (if any) options. How
a Z06 transmission/differential fits in terms of width to the transaxles etc would make a substantial difference as to the cost of such a swap.
What to do about the limited structural integrity of the 928 transmission (AT or 5spd) is about the most significant challenge on a serious build up.
Mark

Warren928

Someone previously mentioned having an AMG modified mercedes transmission parts installed in their shark. I don't know how much horsepower that helped with or who does them. Seems to me the easiest way would be to find a parts list of better clutch packs, gears, etc that will work in there and have them installed. There may be many custom shops that could do a build up but I only know of one. By the time you done modifying the shark to run a different transmission, you cost may eaceed spending money on the one you already own.

Pappy wrote an article about his AMG rebuild below and this would be my recommendation:
"The person who I trust the most is Steve Cattaneo. His business is called Master Tech Transmission and it is located in NY: http://www.mastertechtrans.com/
Steve is incredibly knowledgable and is willing to talk about your requirements. He goes beyond normal levels of detail. Call him if you have questions. He is a transmission specialist. Other people on the list will attest to his credibility."

TeufelHei

I spoke to the folks at Powerhaus II about regearing the 5 speed or creating a one-off six speed in the same transmission case. In both cases (for me) the costs were prohibitive. However, just like all things out there, $$$ talks. I recall (vaguely) the sum of $10-12k for the regearing.

Why would you want a 6 speed from a Z06? The top end gearing is terrible for our cars. With two overdrives, it would be nice for cruising at high speed, but performance issues would be best addressed by reinforcing what we've got.

If I were to spend my money here (if I had it to spend) I'd attack the material reliability, maybe change the gear set, and deffinitely have a new ring gear fabricated. Something in the 3.25:1 range comes to mind. If I was going to go for 6 speed (or more), the first five would still lead up to a 1:1 ratio, anything else after that can be overdrive.

Incidentally, has anyone looked at the BMW transaxles seriously for this?

Vilhuer

It's obviously possible to strenghten 928 5sp box but this gets seriously expensive quickly. Swaping in 6sp from Vette would probably be easier and cheaper too. On automatics AMG parts should be more than enough. Differential and drive shafts will need change on them also when numbers get high enough.

TeufelHei

By the by...how would one go about getting a Z06 tranny anyhow? I don't see a lot of wrecks out there, and I can't imagine them being cheap from GM.

goldknight

you can get teh tranny for around 1500.00 The sucker is about 1 inch longer then a 928 AT tranny. Bad part is the axle location is further forward the the 928 s. this means the thing stick back further to line those up. putting it into the bat. box or very close to it. Then theres the custom cross bar and torque tube.

other then that its easy.
on paper.

WallyP

Old hot rod saying (originally referring to engine swaps)...

Anything will go into anything, if you have a welding torch and a big-enough hammer.

jyoon

changin the r & p to 3.25 would not be a good idea imho. with the added power, it would be too short and you'd have to be shifting gears too often.

have you looked at a mustang tranny? or will that not hold the power? i'd try to stick with something domestic as the parts may be alot cheaper and easier to find.

Vilhuer

Almost all front engine cars have gearboxes mounted right after engine. This means almost all of them have bellhousing as integral part of gearbox casing. This would need to be made smaller to fit at rear of 928. Custon TT isn't easy and cheap to make either. Differential is also needed when using such tranny. Automatic 928's diff would probably be easiest solution but even it takes lot of work and custom parts to mount to any other tranny.