Racing 928 flywheel
02-02-2008, 04:49 PM
#32
Race Director
Now that the clutch can handle just about anything....the next week link is definitely the tranny.....& maybe the TT (since Mark A snapped one recently)....but the layshaft in the tranny seems prone to flexing under all that torque (maybe due to the stronger clutch) & typically 2nd or third gear go bye bye.....
There has to be a way to reinforce the stock tranny....or swap it with something stronger....maybe a GT3-GT2 tranny.....or something race only sequential would be nice....like a hewland or mid valley.....1000hp rated 5 sped with limitless gear ratio options...bummer they start at $10k :>( I think they are lighter too...around 100lbs
There has to be a way to reinforce the stock tranny....or swap it with something stronger....maybe a GT3-GT2 tranny.....or something race only sequential would be nice....like a hewland or mid valley.....1000hp rated 5 sped with limitless gear ratio options...bummer they start at $10k :>( I think they are lighter too...around 100lbs
02-02-2008, 05:06 PM
#33
Nordschleife Master
Making your own G28 internals to your own specs and made of higher quality steel would seem to be allot cheaper then buying then trying to make the GT2 or GT3 transmission fit the 928.
02-02-2008, 05:12 PM
#34
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Of course custom internals means no spares or very expensive spares, not to mention optional gear ratios.
02-02-2008, 05:55 PM
#35
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02-02-2008, 06:14 PM
#36
Further more, the trans we have would be an interesting study. The gear areas is very rectangular. I suppose its a job of recreating the case, and recreating the gears and shafts in a certain way to make it stronger.
02-02-2008, 06:19 PM
#37
Nordschleife Master
Whats wrong with the transmissions?
You guys are talking about this like that editor of the GT porsche magazine who said all 928 blocks are just waiting to crack.
Whats wrong with the G28 ?
You guys are talking about this like that editor of the GT porsche magazine who said all 928 blocks are just waiting to crack.
Whats wrong with the G28 ?
02-02-2008, 06:49 PM
#40
All transmission break I think, its just the limit at which it does. The 20k hewlands (sic) are good for a certain power rating, and I assume if you break them you exceeded it.
02-02-2008, 07:14 PM
#41
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When you nearly double the horsepower and torque fit BIG slicks and put a LOT of hours on it racing.....things sometimes break . That is just part of racing. Street driven cars it is NOT and issue.
02-02-2008, 08:45 PM
#44
Nordschleife Master
I still say the clutch should be the weak link in any drivetrain. Thats a hell of allot easier and cheaper to replace then a transaxle. Allot easier to replace then a drive shaft as well.
I dont know what kind of torque these clutches are that you guys are using but if your engine puts out 500-600 ft/lbs of torque, have a clutch that can handle that, what more can you gain by having a 1000 ft/lb clutch if you dont make that much? Again, i dont know what kind of pressure plates and friction disc's you guys are using so take the above as a simple example.
I would love to hear your theories
I dont know what kind of torque these clutches are that you guys are using but if your engine puts out 500-600 ft/lbs of torque, have a clutch that can handle that, what more can you gain by having a 1000 ft/lb clutch if you dont make that much? Again, i dont know what kind of pressure plates and friction disc's you guys are using so take the above as a simple example.
I would love to hear your theories
02-02-2008, 09:03 PM
#45
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When you get maybe 10 opportunities per year to actually race a car. When you might haul it several hundred miles to do so, When you might just buy $2,000 worth of tires , fly into the race , rent hotel rooms pay $500 ENTRY FEES etc. etc. What does it "COST" when the flat riveted springs break on a stock clutch during your first practice session ??? We know that clutches break and that transmissions break fixing one makes it that much less likely that you have a failure. The issue is not a slipping clutch they break. It may be that the transmission needs a stronger lay shaft to counter act the flex which allows the gears to "unmess" how you do that is the question.