corvette tranny in 928
12-23-2009, 09:59 PM
#16
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On a tubed out full cage racecar the floor pan is not as critical for the ridgity of the body but on a unibody street car the tunnel is a major part of the " frame ". So can it be done ? Yes ! is it simple or cheap ? NOPE ! Do many people need it ? Nope ! Anderson is the only one breaking transmissions on a regular basis but he does not know what the other right foot pedal is used for 
...... So you drop a wheel off the track hit a bit of a bump but there is a little room in front of you entering the corner .....stay on the gas !
...... So you drop a wheel off the track hit a bit of a bump but there is a little room in front of you entering the corner .....stay on the gas !
12-23-2009, 10:16 PM
#17
By IcemanG17
Some F1 cars use a Titanium case covered in carbon fibre, the carbon fibre has great strength in tension. As such if our gearboxes have a problem in relation to the transmission case flexing outwards and the gears moving further apart that could help.
Greg
Weisman makes great transmissions but they are PRICEY.....when I called them for a full race sequential rated to handle 1000tlbs was $30k....
EMCO also makes excellent sequentials, but also pricey...LG motorsports sells theirs for $24.5K
http://www.lgmotorsports.com/catalog...oducts_id=2179
I would imagine it is more cost effective to make stronger internals and possible a stronger case for our transmissions....since T56's rated to handle 1200hp by RSgear, also known as tranzilla are around $5-8k http://www.rsgear.com/transzilla.asp
I would say for a "race" 928 where body mods are easy (think making a much bigger hole) a corvette transaxle would be fairly easy...but on a street car where its much harder to increase room....it gets much tougher
EMCO also makes excellent sequentials, but also pricey...LG motorsports sells theirs for $24.5K
http://www.lgmotorsports.com/catalog...oducts_id=2179
I would imagine it is more cost effective to make stronger internals and possible a stronger case for our transmissions....since T56's rated to handle 1200hp by RSgear, also known as tranzilla are around $5-8k http://www.rsgear.com/transzilla.asp
I would say for a "race" 928 where body mods are easy (think making a much bigger hole) a corvette transaxle would be fairly easy...but on a street car where its much harder to increase room....it gets much tougher
Greg
12-23-2009, 11:30 PM
#18
I just removed my tranny to do some maintenance. I also have a 2004 Z06 tranny that I will be mocking up for craps and giggles. I have looked at the two trannys and the mn12 is much longer however there is a lot of extra room in front of the 5-speed in the tunnel since the auto cars have the torque converter at the front of the trans and the same body is used. In fact the auto in the 928 is a very similar size to the auto trans in the vettes and they use the same body for both auto and 6-speed so I would think, and it looks like, the mn6/12 trans would fit length wise. Height is unknown, but the 5-speed looks taller than the mn12 so we'll see.
I talked to some reputable drivetrain people in DFW about splicing the cv's and they said the least it will cost is 100 for both, but likely double that atleast for each. Vette cv's are female at the trans and sink inside the diff onto the male stub axles. The shafts are also much thicker on the vette so they could be machined down gradually and resplined etc. to fit the outer 928 cv, hence the 200 plus for each axle converted.
For the torque tube there are a few ways to approach it that I was looking into. The vette tube is very different than the 928 tube so this part is just talk, however it was all looked into and found to be reasonably possible.
1. Keep the c5 tube so there is no fitment issues at the rear, just bolts up then have it shortened and the front of the shaft resized/respined to accept the stock 928 pinch clamp shaft and an adapter to mount the tube to the engine. This is the most reasonable solution in my opinion assuming the vette shaft is thicker.
2. Keep the 928 tube and have everything mount up normal at the engine, but make an adapter for the rear to mount the 928 tube to the vette trans and either take another front pinch clamp shaft and connect it to the rear of the 928 shaft and resize/respline the vette input to accept it or make a custom pinch clamp shaft the mate the two.
3. Custom tube altogether. Reason being that the splines on the mn6/12 are on a male shaft and instead of resplining the input for the vette trans just have a custom shaft with a female end that accepts it. Along with a million other ways of makin a custom torque tube mate to two dissimilar parts. Let your mind wander and there are a bunch.
4. By far the easiest way in light of all this to have an mn6/12 6-speed in your 928 is to attach a vette trans and shortened torque tube to a vette or similar engine and make engine and trans mounts.
Basically the main problem, I think, lies with the torque tube. Shifting is even done in the same manner and in a similar location. It is sovleable, but I don't see a completely easy/cheap solution other than possibly option 1. Thats why I am fixing my 5-speed
but still dabbling with the idea of option 1.
I talked to some reputable drivetrain people in DFW about splicing the cv's and they said the least it will cost is 100 for both, but likely double that atleast for each. Vette cv's are female at the trans and sink inside the diff onto the male stub axles. The shafts are also much thicker on the vette so they could be machined down gradually and resplined etc. to fit the outer 928 cv, hence the 200 plus for each axle converted.
For the torque tube there are a few ways to approach it that I was looking into. The vette tube is very different than the 928 tube so this part is just talk, however it was all looked into and found to be reasonably possible.
1. Keep the c5 tube so there is no fitment issues at the rear, just bolts up then have it shortened and the front of the shaft resized/respined to accept the stock 928 pinch clamp shaft and an adapter to mount the tube to the engine. This is the most reasonable solution in my opinion assuming the vette shaft is thicker.
2. Keep the 928 tube and have everything mount up normal at the engine, but make an adapter for the rear to mount the 928 tube to the vette trans and either take another front pinch clamp shaft and connect it to the rear of the 928 shaft and resize/respline the vette input to accept it or make a custom pinch clamp shaft the mate the two.
3. Custom tube altogether. Reason being that the splines on the mn6/12 are on a male shaft and instead of resplining the input for the vette trans just have a custom shaft with a female end that accepts it. Along with a million other ways of makin a custom torque tube mate to two dissimilar parts. Let your mind wander and there are a bunch.
4. By far the easiest way in light of all this to have an mn6/12 6-speed in your 928 is to attach a vette trans and shortened torque tube to a vette or similar engine and make engine and trans mounts.
Basically the main problem, I think, lies with the torque tube. Shifting is even done in the same manner and in a similar location. It is sovleable, but I don't see a completely easy/cheap solution other than possibly option 1. Thats why I am fixing my 5-speed
but still dabbling with the idea of option 1.
