Race 928 transmissions????
09-05-2007, 02:10 AM
#1
Race Director
Thread Starter
Race 928 transmissions????
With the known problems 928 manuals have when dealing with big power 928 race sharks (mostly strokers).....I wonder why someone hasn't changed the stock manual to a newer stronger version...maybe a sequential 6 speed or something similar.....of course sequentials made by hewland or quaife are very expensive ($15K seems to be the cheapest & it goes up from there)...but they are lighter too....some as light as 100lbs that are rated for 600+ft/lbs....more gears, in a stronger package & save 50lbs....but of course it all comes down to $$$$ There has to be something out there that fits....in a transaxle design..
I don't think any race sharks have aftermarket tranny's of any type....the only I've ever heard of is an AMG internal rebuilt automatic?...& there was only one?
I don't think any race sharks have aftermarket tranny's of any type....the only I've ever heard of is an AMG internal rebuilt automatic?...& there was only one?
09-05-2007, 09:53 AM
#4
Addict
Rennlist Member
Rennlist Member
Problem in using any other manual in 928 is that diff needs to be integrated directly after the box and there has to be space for rear subframe too. This drops off most of the candidates that are meant to be mounted to engine anyway. There aren't too many transaxels available and those that exist are very expensive, difficult to mount due to rear subframe etc.
One local 928 races has at least ordered straight cut gear set from local gear shop. These would be for early 928 tranny which can't take tq he has in his Chevy engined racer. Don't know what latest status is. If this case advances at all its probably done by next spring.
There is also 6sp manual conversion project going on locally but its on super slow mode right now as we have too much other stuff to do until next year at least. If it ever materialises it would be much cheaper than $10k quoted for non existing MotoDyne Corvette tranny conversion. Having looked into this I think we have good concept how to do it but its all academic until its actually proven to work. Resulting ratios would be pretty much like ROW S4 with 6th overdrive speed added on top and resulting theoretical top speed depending on max revs somewhere in 230-240 mph range. This would be fully syncronised street tranny which can take stock GTS hp and tq and then some. Most likely it would be stronger than GTS 5sp but maybe fell little short on what strongest 928 automatics can take. It would also use stock rear crossmember, driveshafts etc and only minimum number of non Porsche and custom parts. I think this would be very good way of doing automatic to manual conversion also. If we ever have something solid I'll post more info.
One local 928 races has at least ordered straight cut gear set from local gear shop. These would be for early 928 tranny which can't take tq he has in his Chevy engined racer. Don't know what latest status is. If this case advances at all its probably done by next spring.
There is also 6sp manual conversion project going on locally but its on super slow mode right now as we have too much other stuff to do until next year at least. If it ever materialises it would be much cheaper than $10k quoted for non existing MotoDyne Corvette tranny conversion. Having looked into this I think we have good concept how to do it but its all academic until its actually proven to work. Resulting ratios would be pretty much like ROW S4 with 6th overdrive speed added on top and resulting theoretical top speed depending on max revs somewhere in 230-240 mph range. This would be fully syncronised street tranny which can take stock GTS hp and tq and then some. Most likely it would be stronger than GTS 5sp but maybe fell little short on what strongest 928 automatics can take. It would also use stock rear crossmember, driveshafts etc and only minimum number of non Porsche and custom parts. I think this would be very good way of doing automatic to manual conversion also. If we ever have something solid I'll post more info.
09-05-2007, 10:26 AM
#5
Addict
Rennlist Member
Rennlist Member
We don't want to give out that info just yet. All I can say its readily available used and cheaper than just about anything else with similar specs. How to make it fit is rear problem but we should have working solution to it. Just need to prove it before going public. Aim has been all along that no body modifications are needed and currently this looks doable also.
09-05-2007, 11:06 AM
#6
Captain Obvious
Super User
Super User
09-05-2007, 11:46 AM
#7
Rennlist Member
Don't the majority of racing 928s race in classes that require using stock tranny cases?
Don Hanson cryo-treated some of his gears and was happy with the results, and I think he used some of the 911 synchros.
Don Hanson cryo-treated some of his gears and was happy with the results, and I think he used some of the 911 synchros.
Trending Topics
09-05-2007, 11:48 AM
#8
Rennlist Member
I don't think any race sharks have aftermarket tranny's of any type....the only I've ever heard of is an AMG internal rebuilt automatic?...& there was only one?
09-05-2007, 04:48 PM
#15
Race Director
Thread Starter
I thought most of the ALMS 911's all run 6 speed sequential gearboxes? I guess its allowed in ALMS....
I thought that high dollar 996 RSR turbo that Mark races against has a sequential tranny.....it sure sounds like it on the track based on how fast it shifts?