Our 6-speed Project
01-10-2014, 12:34 PM
#152
What is the O.D. of the new output shaft flanges? I saw your pic/s where you were milling the transmember in that area.
Whoever figures out a way around having to build a new transmember due to inner CV interference will be ahead of the game.
Whoever figures out a way around having to build a new transmember due to inner CV interference will be ahead of the game.
01-10-2014, 01:19 PM
#154
Rennlist Member
In case there is any mis-understanding - The cross-member and kit I am developing is to install the Corvette C5 or C6 manual transaxle in a 928 with manual trans.
....snip.....
I am not developing a Corvette-automatic-into-a-928-with-an-automatic kit. Interesting, but that's not what we are doing at this time. Maybe later.
....snip.....
I am not developing a Corvette-automatic-into-a-928-with-an-automatic kit. Interesting, but that's not what we are doing at this time. Maybe later.
01-10-2014, 01:22 PM
#155
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Jeff - do not despair as the automatic 6 speed with paddle shifters is already being made - join the queue my friend 8>)
__________________
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014
928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission?
George Layton March 2014928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
01-10-2014, 01:31 PM
#156
Because the Auto swap to 928 block does not require a custom Bellhousing nor a custom Torque Tube the only obstacle is negating a custom transmember. If the output flange diameter can be decresed by (?) then the factory transmember can stay put.
01-10-2014, 01:31 PM
#157
Rennlist Member
guys, the rear end discussion is always a lot of hype. with a 4.11 or a 3.74, or even a 928 cruiser 2.2, the end result can be the same...... in fact, the standard C5 with a 4.11 has final ratio of 2.0. 
almost 10% taller than the 928. even its 5th gear , would be slightly taller than our S4 2.2:1 4th gear (i.e. 3.0 vs our 3.2:1) Having raced many of these vets over the years, the actual shift points are near the same as the stock S4 928 gear box. (redline vs road speed in each gear on the track) (as a side note, the stock vet C5 has a 5th gear that is equal to the 2.75 rear end of the GTS.
Gear LS1/MM6 LS6/M12
1st Gear 2.66:1 2.97:1
2nd Gear 1.78:1 2.07:1
3rd Gear 1.30:1 1.43:1
4th Gear 1.00:1 1.00:1
5th Gear 0.74:1 0.84:1
6th Gear 0.50:1 0.56:1
Reverse 2.90:1 3.28:1
Axle Ratio varies 3.42:1
Final Drive Ratio varies 1.91:1
almost 10% taller than the 928. even its 5th gear , would be slightly taller than our S4 2.2:1 4th gear (i.e. 3.0 vs our 3.2:1) Having raced many of these vets over the years, the actual shift points are near the same as the stock S4 928 gear box. (redline vs road speed in each gear on the track) (as a side note, the stock vet C5 has a 5th gear that is equal to the 2.75 rear end of the GTS.Gear LS1/MM6 LS6/M12
1st Gear 2.66:1 2.97:1
2nd Gear 1.78:1 2.07:1
3rd Gear 1.30:1 1.43:1
4th Gear 1.00:1 1.00:1
5th Gear 0.74:1 0.84:1
6th Gear 0.50:1 0.56:1
Reverse 2.90:1 3.28:1
Axle Ratio varies 3.42:1
Final Drive Ratio varies 1.91:1
01-10-2014, 01:32 PM
#158
In case there is any mis-understanding - The cross-member and kit I am developing is to install the Corvette C5 or C6 manual transaxle in a 928 with manual trans.
It could also be used to convert a 928 with automatic to a 6-speed manual. You would have to get the other bits from Mark or Tom at 928 Intl (the manual flywheel, clutch, bell housing, throw-out bearing, clutch master and slave and other bits). We will be providing the torque tube. Fortunately, the C5 and C6 transaxles are selling for less than a good used G28 trans. That'll help. There are really good threads on the automatic-to-5-speed conversion here on the Renn.
I am not developing a Corvette-automatic-into-a-928-with-an-automatic kit. Interesting, but that's not what we are doing at this time. Maybe later.
It could also be used to convert a 928 with automatic to a 6-speed manual. You would have to get the other bits from Mark or Tom at 928 Intl (the manual flywheel, clutch, bell housing, throw-out bearing, clutch master and slave and other bits). We will be providing the torque tube. Fortunately, the C5 and C6 transaxles are selling for less than a good used G28 trans. That'll help. There are really good threads on the automatic-to-5-speed conversion here on the Renn.
I am not developing a Corvette-automatic-into-a-928-with-an-automatic kit. Interesting, but that's not what we are doing at this time. Maybe later.
Awwww....I know what "maybe later" means. Heard that a lot through my childhood. Well, major props Carl. If you ever get it to, please please please do.
01-10-2014, 01:38 PM
#160
Developer
Thread Starter
xschop - I agree with you and we are trying to do this in such a way that the OEM transaxle (with some modification) can still be used. We'll see. I know other non-kit (custom installs) who have already done this have had to go the route of making an all-new cross-member, and those guys are not stupid.
I just haven't ruled it out yet and so far, we have been able to re-machine a stock cross-member to do the job.
I should know in 2 weeks or less if this is going to work. If it doesn't, we will be making a cross-member from scratch also.
I just haven't ruled it out yet and so far, we have been able to re-machine a stock cross-member to do the job.
I should know in 2 weeks or less if this is going to work. If it doesn't, we will be making a cross-member from scratch also.
01-10-2014, 01:48 PM
#161
Official Bay Area Patriot
Fuse 24 Assassin
Rennlist Member
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Rennlist Member
01-10-2014, 02:03 PM
#163
Official Bay Area Patriot
Fuse 24 Assassin
Rennlist Member
Fuse 24 Assassin
Rennlist Member
Which V12 is he using, or thinking of?
Also, would the transmission for the 6-speed auto be the 6L80E used in 2006+ Corvettes (C6 Generation)?
EDIT - Don't mean to derail your thread here Carl. I apologize.
Also, would the transmission for the 6-speed auto be the 6L80E used in 2006+ Corvettes (C6 Generation)?
EDIT - Don't mean to derail your thread here Carl. I apologize.
Last edited by Mongo; 01-10-2014 at 03:12 PM.
01-11-2014, 03:54 PM
#165
Developer
Thread Starter
I found a thread discussing the 6-speed automatic swap into a automatic-equipped 928.
It may already have answers to your automatic 6-spd upgrade questions on it:
https://rennlist.com/forums/928-foru...l#post11043575
It may already have answers to your automatic 6-spd upgrade questions on it:
https://rennlist.com/forums/928-foru...l#post11043575