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Corvette 6 spd in place of 928 AT?

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Old 10-05-2005 | 01:19 PM
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What about the BMW 6 speed out of a Z8? Pricey for sure, but doesn't that car have a rear mounted trans?
Old 10-05-2005 | 01:37 PM
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Z8 is all M5 underneath meaning gearbox is extension to the engine.
Old 10-05-2005 | 02:02 PM
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Originally Posted by TeufelHei
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.
I have a 3.09 gearset in my stroked GTS. That is overkill... 3.25 would be completely useless. For a big motor car, a lower numerical ratio would be preferred. 6k rpms just come to damn quickly. 5th is maxed out at around 140 mph. But boy is it fun getting there.
Old 10-05-2005 | 02:05 PM
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Scott, how did you get a 3.09 gearset?
Old 10-05-2005 | 02:12 PM
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Originally Posted by BrianG
Scott, how did you get a 3.09 gearset?

BG;

I got them the easy way, I bought the car with them in it.

Talking with builder (most of the stuff anyway) of my car, he mentioned that they were made as a one off by a US firm. There was a Pano article about 6-7 years ago where a Canadian firm made a few sets.
Old 10-05-2005 | 02:29 PM
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Originally Posted by Tony
Spend your time, $$$ and energy to get 600HP first IMHO.
That alone will be a long enough and $$$ journey.
Tony,
That can be resolved with a phone order to Jegs. Plenty to choose from crate motors over 700 hp NA at half the price and aggravation of a 928 engine. I'm having a bad 928 week. It won't take much to persuade me to go Porshev or all out rice at this point.
Old 10-05-2005 | 02:32 PM
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It would be nice if we could swap in a transmission like the Mercedes NSG 370 6speed.
With
4.46,
2.61,
1.72,
1.25,
1,
0.84,

It would even work ok with the 2.2 gears of the 4 speed auto. A 3.10 final drive would be perfect. I would probably look at doing this but don't know if this trans can take enough torque for the 32V much less a SCed one. The only spec I can find is 272ft/lbs. May be something just for the 16v cars.
This is the same transmission from the Crossfire but virtually all car transmissions have a long tail housing at the back that make mating it to the 928 automatic differential housing impractical/impossible. It is in the 2005 Jeeps as well. The Jeep transmissions do have a 6 bolt flange at back for a transfer case and this would allow for attaching the automatic's differential housing. The Jeep transmission retails for around $1650. With flywheel, clutch, throwout bearing, slave cylinder, and clutch arm the total is around $2200.00. The Crossfire trans is virtually the same trans with a different casing but retails over $3000.
The Rubicon version including the bell housing is about 1/4" shorter than the 928 4 speed auto. However the bell housing is one piece with the trans case. This means the clutch would be in the rear like the 968. The problem is that the bell housing would need 2-3 inches more space than the transmission tunnel of the 928 automatic allows at the front 4 inches or so of the big buldge between the rear seats. The remedy would be to cut an opening to give a little more space around the bell housing and then fashion new sheetmetal to cover those slots and reinforce the area.
Another issue is that the shifter sticks straight up and would enter the passenger compartment between the rear seats. You could easily build a linkage but still the linkage would be in the passanger's compartment. It wouldn't be that high and could probably be concealed pretty easily.
In conclusion at this point I would say it is a viable project for a 16v automatic that isn't concerned with rear passengers.

Andy
Old 10-05-2005 | 02:33 PM
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Originally Posted by 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.
That's what I like to hear. Monster garage makes it look easy. Not always elegant, but reasonably doable.

My superwidebody is ready for a good welder with skills of a surgeon. Can anyone here do it for a reasonable fee? I could learn welding and get it done myself, but I can't handle any more projects at this point.
Old 10-05-2005 | 02:38 PM
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who "broke" trannies due to high hp here anyway? Devek? Tammons? what exactly was the weak link?
Old 10-05-2005 | 02:40 PM
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Originally Posted by TAREK
.......a good welder with skills of a surgeon.... for a reasonable fee?

Hey, Tarek, share whatever it is that you're smoking!!
Old 10-05-2005 | 02:55 PM
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Originally Posted by IcemanG17
What about the BMW 6 speed out of a Z8? Pricey for sure, but doesn't that car have a rear mounted trans?
The new Aston Martin V8 Vantage (the new 928 to some) has a rear mounted 6spd. Maybe it's a reworked Ford box? If so it might be affordable.

EDIT: Just looked it up and it's a Tremec T-56 just like the Vet (and Viper too):
http://www.ttcautomotive.com/English/products/T-56.asp
Still, maybe the case for the AM is more suited for a shark? Malibu, when do you get your Vantage? Can we borrow it for a weekend to take it apart?

BTW: The beefyist T-56 they show is rated for 550 ft-lbs (although Hennessey make a viper mod that makes 1100 ft-lbs! http://www.roadandtrack.com/article....page_number=15 ).
Old 10-05-2005 | 04:01 PM
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Originally Posted by TAREK
....I'm having a bad 928 week. It won't take much to persuade me to go Porshev or all out rice at this point.
NO TAREK!!! Don't do it!

Do I need to come down there for an "intervention??"
Old 10-05-2005 | 04:35 PM
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Try this:
http://www.motodyne.com/frames/porsche_928_6spd.html
Old 10-05-2005 | 04:39 PM
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Originally Posted by jenyap
I was wondering when someone would bring up the (in)famous Robert Hack.
Old 10-05-2005 | 05:04 PM
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Originally Posted by 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.
WOW. OK
Seeing what Don Hanson and Marc Thomas, Mark Anderson and joeseph Fan have done and the time and effort it has taken in there NA cars to hit the 500-575 rwhp level, "all the power ''(pun intended) to you for an unchallenging journey!

Would you like catchup with those words?


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