Got my car back! Re-gearing done!
09-24-2004, 05:14 PM
#61
Race Car
Thread Starter
P.S. a slight edge might be that the valve timing settings out of the factory are imprecise on the 997 S as opposed to my car and it does not have a LWF...
09-24-2004, 06:39 PM
#62
RL Technical Advisor
Greg:
Although the TT has better gear ratios than its naturally aspirated cousins do, you would be surprised what a difference a custom close-ratio gearstack does with these cars.
Even though they are better, its a far cry from optimal for acceleration and performance. CAFE laws made Porsche compromise many things,.....
Although the TT has better gear ratios than its naturally aspirated cousins do, you would be surprised what a difference a custom close-ratio gearstack does with these cars.
Even though they are better, its a far cry from optimal for acceleration and performance. CAFE laws made Porsche compromise many things,.....
09-24-2004, 07:26 PM
#64
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
[
I am sure I would be surprised, if it is that much better than the stock set. Not like these cars don't pull hard enough in stock form. 
Anyone have a TT with short gears I can try out? Promise to be gentle.
=Steve Weiner-Rennsport Systems]Greg:
Although the TT has better gear ratios than its naturally aspirated cousins do, you would be surprised what a difference a custom close-ratio gearstack does with these cars.
Although the TT has better gear ratios than its naturally aspirated cousins do, you would be surprised what a difference a custom close-ratio gearstack does with these cars.
Not like these cars don't pull hard enough in stock form. Anyone have a TT with short gears I can try out? Promise to be gentle.
09-24-2004, 07:39 PM
#65
RL Technical Advisor
Jauder:
About the same,......Its a situation when you are never left "waiting for the elevator" (waiting for max acceleration) and the car is always in its best RPM range between peak torque and peak HP.
About the same,......Its a situation when you are never left "waiting for the elevator" (waiting for max acceleration) and the car is always in its best RPM range between peak torque and peak HP.
09-24-2004, 08:26 PM
#66
Burning Brakes
Originally Posted by garychios
How much does this gearing mod cost?
09-25-2004, 07:47 AM
#67
Rennlist Member
I have been thinking about something like this for some time as top speed is of less relevance to me on a daily basis, but am concerned that for daily driving there may be an excessive amount of gear changing involved. this is something that is still holding me back given my slightly lazy left foot....
10-01-2004, 07:46 AM
#68
Race Car
Thread Starter
Car is a blast!
I have been driving and driving ever since I had the work done. The character of the car has changed completely! Reminds me of the old 1973 Carrera 2.7 RS in responsiveness!
This is addicitve! The car takes off like a rocket! Instant power!
This is addicitve! The car takes off like a rocket! Instant power!
10-02-2004, 02:30 AM
#72
RL Technical Advisor
Originally Posted by p_carfan
Steve W. Can you chime in here? What do you think an approximate cost of this mod might be. I've been considering the G50/21 gearbox and this might be a better alternative.
All I can offer is APPROXIMATE costs as each case will be different.
Transmissions are THE most abused and mistreated parts of a car and the most subject to owner-derived wear & tear. For that reason, the parts costs of such projects depends on the parts required to rebuild the tranny. Other factors are whether you have a fixed or free 2nd gear and if your LSD needs to be rebuilt (most do at 25K or more).
Some ballpark figures:
4 Gearsets at; $ 850/each (GT Gears)
Motorsport steel syncros (full set); $ 2100
Mainshaft (if needed); $ 1250
Overhaul parts can range from $ 250 to $600 depending on what is found.
LSD overhaul runs around $ 550 for parts & labor
Labor rates vary but we charge 12-16 hours to do the tranny after its out of the car. The variation is due to whether the LSD is overhauled or not.
Not cheap, as you can plainly see but this represents THE biggest bang-for-the-buck that you can do to improve the acceleration of these cars. Its far better than a 3.8 RS conversion and a lot less expensive.
IMHO, the G-50/21 is a much more modest upgrade compared to a custom set of ratios chosen specifically for your car and how YOU use it.
10-05-2004, 02:04 PM
#73
Pro
Join Date: Jan 2004
Location: NYC
Posts: 607
Likes: 0
Received 0 Likes
on
0 Posts
If your car shifts smootly, gears work nice and you have no problems, can you assume that the rebuild will be cheaper? Why do you rebuild the LSD? I have run LSD's for years in high horsepower cars without rebuilds. Can you please explain?
10-05-2004, 10:22 PM
#74
RL Technical Advisor
Gary:
Its really dependent on the result of a competant & experienced inspection and assessment. One should not use worn operating sleeves with new gears as that simply accelerates wear of the engagement teeth on each gearset. IMHO, thats just false economy based on the cost of R&R'ing the tranny and opening it up again.
Regarding the 993 LSD's,......
Porsche made some cost-cutting measures in the design & manufacture of these differentials and these units contain half the number of drive & driven plates of their forebears found in 964-911-930 cars. The early ZF LSD's contained 4 plates per side but the 993 (and GT-3) ones have only 2 plates per side. This means that you get less than half the lifespan on these units before the plates need replacing to maintain functionality.
Typically, the 993 LSD's are worn out by 25K-30K miles depending on usage. Porsche publishes the breakaway torque specs and the LSD can be tested in the car by disconnecting the axles and checking the LSD with a holding fixture on one side & a torque wrench on the other.
When one finds a worn LSD, there are a few options (some better than others):
1) Replace all 4 drive & driven plates.
2) Replace 993 OEM LSD with Factory Motorsports one; this is a 4-plate one; (8 plates total) and much more durable. These last 50K or more.
3) Replace 993 OEM LSD with a GT Transmission 4340 chrome-moly-cased one. These are far stronger than the Motorsports ones and last just as long.
Hope this answers your questions.
Its really dependent on the result of a competant & experienced inspection and assessment. One should not use worn operating sleeves with new gears as that simply accelerates wear of the engagement teeth on each gearset. IMHO, thats just false economy based on the cost of R&R'ing the tranny and opening it up again.
Regarding the 993 LSD's,......
Porsche made some cost-cutting measures in the design & manufacture of these differentials and these units contain half the number of drive & driven plates of their forebears found in 964-911-930 cars. The early ZF LSD's contained 4 plates per side but the 993 (and GT-3) ones have only 2 plates per side. This means that you get less than half the lifespan on these units before the plates need replacing to maintain functionality.
Typically, the 993 LSD's are worn out by 25K-30K miles depending on usage. Porsche publishes the breakaway torque specs and the LSD can be tested in the car by disconnecting the axles and checking the LSD with a holding fixture on one side & a torque wrench on the other.
When one finds a worn LSD, there are a few options (some better than others):
1) Replace all 4 drive & driven plates.
2) Replace 993 OEM LSD with Factory Motorsports one; this is a 4-plate one; (8 plates total) and much more durable. These last 50K or more.
3) Replace 993 OEM LSD with a GT Transmission 4340 chrome-moly-cased one. These are far stronger than the Motorsports ones and last just as long.
Hope this answers your questions.
