928 Racer with 6-Speed Manual Transmission
03-30-2009, 10:47 AM
#31
Racer
I have a feeling that this is the original car built by Porsche in 1990 to compete in the GT cup. It used to be run by RDM Racing and now sold to BSMotors... I will be at the Nurburgring in May so I would try and talk to the father & son and get their secrets out...
Overall, a very nice built. I wish I can get mine to be as good as this one and still be street legal...
Overall, a very nice built. I wish I can get mine to be as good as this one and still be street legal...
Do you know, if several car has been used to develop 928 GT cup?
For the car, I don't really undertsand why they use a 968 turbo RS gear box. Perhaps they already have it or buy it at a very fair price?
Puyi
03-30-2009, 12:08 PM
#33
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Normal 968 gearbox layout is totally different than 928. If turbo S box has similar setup as I suspect it has they have moved a lot of weight further back behind rear axle line.
03-30-2009, 12:33 PM
#34
Nordschleife Master
I'd like to see some pics.
The 968 tranny is very different than the 928. It has a much larger front flange and has the outputs much closer to the front of the tranny. The gears are actually to the rear from where the half shafts attach. The first time I saw one, I was sure it was for a 911. Looks more like those. FWIW, I've swapped the trannies in both of my cars.
It'd be a lot of work to make that fit. Nothing money can't fix, of course.
The 968 tranny is very different than the 928. It has a much larger front flange and has the outputs much closer to the front of the tranny. The gears are actually to the rear from where the half shafts attach. The first time I saw one, I was sure it was for a 911. Looks more like those. FWIW, I've swapped the trannies in both of my cars.
It'd be a lot of work to make that fit. Nothing money can't fix, of course.
03-30-2009, 01:41 PM
#35
Nordschleife Master
FYI. the 968 tranny, as well as the 924/944 tranny (924NA has a smaller input shaft), are an audi based transmission. If you look at an audi coupe GT or audi 5000 etc alot of them have trannies that look exactly the same in them and would most likely simply bolt right up.
03-30-2009, 01:50 PM
#36
Administrator - "Tyson"
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If this transmission is from a 1 of 4 968 race car, trying to compare it to a stock 924/944 transmission is a bit silly. Same goes for a factory built 928 race car.
All that sdie, a good fabricator could fit a muncie 4-speed into a 928 if they wanted to.
All that sdie, a good fabricator could fit a muncie 4-speed into a 928 if they wanted to.
03-30-2009, 03:00 PM
#37
Nordschleife Master
Erik,
I know what you are saying, but from the info I have on those gear boxes is that they were the same case, but beefed up and different internals.
If they had said it was 1 of the 4 924 GTR transmissions then that would be a different story, but those were 4 speeds only. and based on a G31 snailshell.
I know what you are saying, but from the info I have on those gear boxes is that they were the same case, but beefed up and different internals.
If they had said it was 1 of the 4 924 GTR transmissions then that would be a different story, but those were 4 speeds only. and based on a G31 snailshell.
03-30-2009, 04:40 PM
#38
Race Director
guys.....if you were to put a 944-951-968 tranny right next to a 928 tranny.....I would say its 1/2 the size, maybe less at the rear.....those things really weren't designed for big torque like a 928 makes..... I do know of a 951-LS1 conversion that is used for trackdays with good success....but I don't think I would want to spend the $$$ to find out its weaker than my stock tranny....
A G50 conversion or T56 is another story however
A G50 conversion or T56 is another story however
03-30-2009, 04:57 PM
#39
Racer
guys.....if you were to put a 944-951-968 tranny right next to a 928 tranny.....I would say its 1/2 the size, maybe less at the rear.....those things really weren't designed for big torque like a 928 makes..... I do know of a 951-LS1 conversion that is used for trackdays with good success....but I don't think I would want to spend the $$$ to find out its weaker than my stock tranny....
A G50 conversion or T56 is another story however
A G50 conversion or T56 is another story however
I don't think the 951 tranny is worse than 928 getrag. I didn't read anything about problem with 951 tranny which support 400 hp- 400 lbs. indeed, I heard lot about 928 tranny!!
That week end I saw a G28/09 and a 968 tranny, although the two are very different but 968 tranny is not 1/2 the size of the 928. Really they are not so different.
Puyi
03-30-2009, 05:03 PM
#40
Rennlist Member
the right way to do this, would to just make our gears closer. the 2.2 already has the right first gear for getting on the track and any real tight hairpins.
1st50mph
2nd 80mph
3rd 120mph
4th 155mph
all you need to do is find a way to keep 1st the same and bring down 2nd, 3rd and 4th and use a 3.10 for 5th. The 3.10 doesnt do anything but make a normal GTS a S4 at the end of the day (3.2 is an s4s 4th gear) BUT, if you were able to change the ratios to do something proven like the cup cars at
1 50mph
2 75mph
3 95mph
4th 120mph
5th 155mph. you would have all the benefits of a racing tranmission but in our case.
there is no magic in a 6 speed in this case, unless you also want to go to tracks where you want a top speed above 170mph, like cal speedway or RA.
Then, adjust from there. a gear modified GTS gear box would be good for that, but you would have to sacrafice 1st and make it taller than a normal 928.
I think we need a sequential shifter version of the 928 gear box
mk
1st50mph
2nd 80mph
3rd 120mph
4th 155mph
all you need to do is find a way to keep 1st the same and bring down 2nd, 3rd and 4th and use a 3.10 for 5th. The 3.10 doesnt do anything but make a normal GTS a S4 at the end of the day (3.2 is an s4s 4th gear) BUT, if you were able to change the ratios to do something proven like the cup cars at
1 50mph
2 75mph
3 95mph
4th 120mph
5th 155mph. you would have all the benefits of a racing tranmission but in our case.
there is no magic in a 6 speed in this case, unless you also want to go to tracks where you want a top speed above 170mph, like cal speedway or RA.
Then, adjust from there. a gear modified GTS gear box would be good for that, but you would have to sacrafice 1st and make it taller than a normal 928.
I think we need a sequential shifter version of the 928 gear box
mk
guys.....if you were to put a 944-951-968 tranny right next to a 928 tranny.....I would say its 1/2 the size, maybe less at the rear.....those things really weren't designed for big torque like a 928 makes..... I do know of a 951-LS1 conversion that is used for trackdays with good success....but I don't think I would want to spend the $$$ to find out its weaker than my stock tranny....
A G50 conversion or T56 is another story however
A G50 conversion or T56 is another story however
03-30-2009, 05:04 PM
#41
Race Director
Puyi
take a look here
http://www.tonygarcia.org/944V8/tran...s.cooler.1.jpg
http://www.tonygarcia.org/944V8/tran...-3.28.08/5.jpg
Remember the trans is behing the "rear end" in the 944's....thats where all the gears are.....vs a 928 which is basically a huge rectangle...... Yes we do hear of 928's blowing transmissions...but there is a HUGE difference in the power output of the 928 motor vs a turbo 951, which doesn't make peak torque until pretty high in the rpms.....a stroked 928 can easily put down 400+ torque to the ground at under 3000rpm...much more strain on the transmission!
take a look here
http://www.tonygarcia.org/944V8/tran...s.cooler.1.jpg
http://www.tonygarcia.org/944V8/tran...-3.28.08/5.jpg
Remember the trans is behing the "rear end" in the 944's....thats where all the gears are.....vs a 928 which is basically a huge rectangle...... Yes we do hear of 928's blowing transmissions...but there is a HUGE difference in the power output of the 928 motor vs a turbo 951, which doesn't make peak torque until pretty high in the rpms.....a stroked 928 can easily put down 400+ torque to the ground at under 3000rpm...much more strain on the transmission!
03-30-2009, 05:09 PM
#42
Race Director
1st: 48
2nd: 72
3rd: 101
4th: 133
5th: 181
03-30-2009, 07:36 PM
#43
Rennlist Member
Yes, there is another car, which is currently in France and was built by Turbo-Technik-Pietz - a famous German Tuner, with Porsche's help. There is also the Castrupp-Wachmaier Car, which I have not been able to trace...
03-30-2009, 08:28 PM
#44
Former Vendor
03-31-2009, 07:37 AM
#45
Racer
Puyi
take a look here
http://www.tonygarcia.org/944V8/tran...s.cooler.1.jpg
http://www.tonygarcia.org/944V8/tran...-3.28.08/5.jpg
Remember the trans is behing the "rear end" in the 944's....thats where all the gears are.....vs a 928 which is basically a huge rectangle...... Yes we do hear of 928's blowing transmissions...but there is a HUGE difference in the power output of the 928 motor vs a turbo 951, which doesn't make peak torque until pretty high in the rpms.....a stroked 928 can easily put down 400+ torque to the ground at under 3000rpm...much more strain on the transmission!
take a look here
http://www.tonygarcia.org/944V8/tran...s.cooler.1.jpg
http://www.tonygarcia.org/944V8/tran...-3.28.08/5.jpg
Remember the trans is behing the "rear end" in the 944's....thats where all the gears are.....vs a 928 which is basically a huge rectangle...... Yes we do hear of 928's blowing transmissions...but there is a HUGE difference in the power output of the 928 motor vs a turbo 951, which doesn't make peak torque until pretty high in the rpms.....a stroked 928 can easily put down 400+ torque to the ground at under 3000rpm...much more strain on the transmission!
I remember Thread about 928 transmission failure on 928 which are just normal one. But you are right, stroker or SS 928 make high torque @ middle range RPMs. And really I don't know what were the reliability of 951 gear box in that case.
What I am wondering is why they use 968 gear box. What was the goal? Or Is it the only way they found to have a motor mounted 12 cm back on the car, a torque tub as normal and a gear box which allow the mount of CV joints as normal?
Puyi