3 track days = toasted LSD on Gt2 , need advice..
04-05-2010, 12:58 AM
#16
Race Director
guys, I have a 2009 Carrera S that came with LSD. When you order Sport PASM, Porsche includes a LSD. I have not idea what type of LSD is in the car and my car has PDK...not sure if a different LSD is in my car than everyones GT3 LSD on this forum.
I have 11,000 miles on my car and 12 DE's. I guess my LSD is shot...not sure but even new under hard threshold braking from 125mph into turn 7 at Sebring my tail has always wiggled. Other than that I have no idea the health of my LSD.
What upgrade for a car like mine that is tracked, driven to the track and driven weekly on the street? I am not capable of doing any removal my self so anyone know what kind of labor cost and rebuilding upgrade cost I might be looking at if I decide to do this? How long does the upgraded LSD last?
I have 11,000 miles on my car and 12 DE's. I guess my LSD is shot...not sure but even new under hard threshold braking from 125mph into turn 7 at Sebring my tail has always wiggled. Other than that I have no idea the health of my LSD.
What upgrade for a car like mine that is tracked, driven to the track and driven weekly on the street? I am not capable of doing any removal my self so anyone know what kind of labor cost and rebuilding upgrade cost I might be looking at if I decide to do this? How long does the upgraded LSD last?
04-05-2010, 02:34 AM
#17
Addict
Rennlist Member
Rennlist Member
guys, I have a 2009 Carrera S that came with LSD. When you order Sport PASM, Porsche includes a LSD. I have not idea what type of LSD is in the car and my car has PDK...not sure if a different LSD is in my car than everyones GT3 LSD on this forum.
I have 11,000 miles on my car and 12 DE's. I guess my LSD is shot...not sure but even new under hard threshold braking from 125mph into turn 7 at Sebring my tail has always wiggled. Other than that I have no idea the health of my LSD.
What upgrade for a car like mine that is tracked, driven to the track and driven weekly on the street? I am not capable of doing any removal my self so anyone know what kind of labor cost and rebuilding upgrade cost I might be looking at if I decide to do this? How long does the upgraded LSD last?
I have 11,000 miles on my car and 12 DE's. I guess my LSD is shot...not sure but even new under hard threshold braking from 125mph into turn 7 at Sebring my tail has always wiggled. Other than that I have no idea the health of my LSD.
What upgrade for a car like mine that is tracked, driven to the track and driven weekly on the street? I am not capable of doing any removal my self so anyone know what kind of labor cost and rebuilding upgrade cost I might be looking at if I decide to do this? How long does the upgraded LSD last?
04-05-2010, 02:37 AM
#18
Addict
Rennlist Member
Rennlist Member
This!
TTurbine,
Does your car spin an inside wheel on corner exit? Does your tail wag when you brake hard from 100mph+ to try and get speed down before entering a slow corner? These are the on track things you will generally experience if you diff. is shot.
The old spin test is pretty much out the window on the new generation of street differentials. Porsche has gone to low, or in the case of the Cayman, a no preload design. If you want to aggressively by hand spin a wheel using the old "spin test" methodology you might be able to feel some resistance if you can shock load the thing hard enough by hand to get it to start to lock. But it's still not really going to tell you much.
Here's the bottom line, as is being laid out in the FAQ thread that was posted recently: The crappy brass friction discs they are using don't have a very high coefficient of friction. They don't lock very well or very hard even when they are brand new. Preload or no reload isn't really a question given the use of those discs. Some guys are putting more preload into the diffs and getting them to "work" longer but that still doesn't change the ramp angles.
That's issue number 2. As mentioned above, Porsche made the new locking percentages very low at 28/40. This is compared to the 40/60 that was on the 996 GT3. But even in the 996, the GT2 got the less aggressive ramps. If you want more lock out of your diff. you're going to want to change the ramps. There's really no way around that.
If they haven't "worn out" already, the brass discs in your car will "wear out" soon. I put those in quotes because when they come out they show very little wear. That's because they don't bite hard enough. So, even though they come out looking brand new, they aren't doing their job. You can keep your stock ramps if you want a more forgiving car, or you can change them to something with more bite. Regardless, I encourage you to get rid of the stock brass discs and definitely install a friction disc with more bite.
Regards,
Matt Monson
TTurbine,
Does your car spin an inside wheel on corner exit? Does your tail wag when you brake hard from 100mph+ to try and get speed down before entering a slow corner? These are the on track things you will generally experience if you diff. is shot.
The old spin test is pretty much out the window on the new generation of street differentials. Porsche has gone to low, or in the case of the Cayman, a no preload design. If you want to aggressively by hand spin a wheel using the old "spin test" methodology you might be able to feel some resistance if you can shock load the thing hard enough by hand to get it to start to lock. But it's still not really going to tell you much.
Here's the bottom line, as is being laid out in the FAQ thread that was posted recently: The crappy brass friction discs they are using don't have a very high coefficient of friction. They don't lock very well or very hard even when they are brand new. Preload or no reload isn't really a question given the use of those discs. Some guys are putting more preload into the diffs and getting them to "work" longer but that still doesn't change the ramp angles.
That's issue number 2. As mentioned above, Porsche made the new locking percentages very low at 28/40. This is compared to the 40/60 that was on the 996 GT3. But even in the 996, the GT2 got the less aggressive ramps. If you want more lock out of your diff. you're going to want to change the ramps. There's really no way around that.
If they haven't "worn out" already, the brass discs in your car will "wear out" soon. I put those in quotes because when they come out they show very little wear. That's because they don't bite hard enough. So, even though they come out looking brand new, they aren't doing their job. You can keep your stock ramps if you want a more forgiving car, or you can change them to something with more bite. Regardless, I encourage you to get rid of the stock brass discs and definitely install a friction disc with more bite.
Regards,
Matt Monson
Thanks for stepping in to clarify the issue. One thing I know for sure is OEM LSD will not hold up more than 1-2 track event as reported by everyone and clearly demonstrated by my LSD on bench testing. I love my rebuild LSD and no issue with control on the track.
04-05-2010, 09:36 AM
#19
Three Wheelin'
So is a Worn LSD covered under warranty? or is it the same as a Clutch scenario?
04-05-2010, 12:37 PM
#21
Nordschleife Master
I have only come across one dealership that was willing to do a sort of half-n-half warranty. The customer managed to talk his dealership into covering the labor to remove the LSD and rebuild it, but the customer purchased our parts, which he provided to the technician to use in it. It took the guy over a week of negotiating and him signing an agreement that if there was ever a problem in the future, the LSD no longer had any warranty coverage on it.
I've also had several customers have the the LSD rebuilt under warranty, using Porsche parts, and when the LSD failed a second time the warranty was then declined.
I've also had several customers have the the LSD rebuilt under warranty, using Porsche parts, and when the LSD failed a second time the warranty was then declined.
04-05-2010, 06:29 PM
#22
Pro
Thread Starter
Thanks guys for the support, I decided to go with 40/60 rebuilt LSD for my GT2 and GT3 as per Matts recommendation.
A big thanks to Matt he was very helpful and handled my many questions in a prompt and professional way
Hopefully I will send my LSD within these 2 days.
Will keep you guys updated about the results
Moe
A big thanks to Matt he was very helpful and handled my many questions in a prompt and professional way
Hopefully I will send my LSD within these 2 days.
Will keep you guys updated about the results
Moe
04-06-2010, 01:16 AM
#23
Addict
Rennlist Member
Rennlist Member
Thanks guys for the support, I decided to go with 40/60 rebuilt LSD for my GT2 and GT3 as per Matts recommendation.
A big thanks to Matt he was very helpful and handled my many questions in a prompt and professional way
Hopefully I will send my LSD within these 2 days.
Will keep you guys updated about the results
Moe
A big thanks to Matt he was very helpful and handled my many questions in a prompt and professional way
Hopefully I will send my LSD within these 2 days.
Will keep you guys updated about the results
Moe
