Limited Slip Differential?
06-24-2005, 06:33 AM
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Limited Slip Differential?
Excuse my ignorance, but does the 997 come with a limited slip differential?
I noticed on an option list that the P17 Sports Suspension, which is not available in the US, comes with a "mechanical rear differential lock". I'm not sure if this is a superior limited slip unit, or is the ONLY limited slip unit (meaning limited slip is not available in the US).
Michael
I noticed on an option list that the P17 Sports Suspension, which is not available in the US, comes with a "mechanical rear differential lock". I'm not sure if this is a superior limited slip unit, or is the ONLY limited slip unit (meaning limited slip is not available in the US).
Michael
06-24-2005, 10:02 AM
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The 997 fitted with the P17 -20mm Sport Suspension (optional here in Europe for no cost in the 997S) comes with a rear LSD. Along with the benefits of PSM too, which in turn has even an extra much sportier setting if you get the Sport Chrono Option.
The other 997 versions (like PASM) don't have a mechanical LSD, just the electronic ABD (Automatic Brake Differential) of the PSM.
The P17 sport suspension is incredible, don't know if its the LSD or the new chasis or stiffer setup, but its light years ahead of the M030 Sport Suspension of the 996. A shame its not offered in the US.
The other 997 versions (like PASM) don't have a mechanical LSD, just the electronic ABD (Automatic Brake Differential) of the PSM.
The P17 sport suspension is incredible, don't know if its the LSD or the new chasis or stiffer setup, but its light years ahead of the M030 Sport Suspension of the 996. A shame its not offered in the US.
06-24-2005, 10:33 AM
#4
Originally Posted by Carlos from Spain
The 997 fitted with the P17 -20mm Sport Suspension (optional here in Europe for no cost in the 997S) comes with a rear LSD.
06-24-2005, 11:44 AM
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Race Car
Supposedly because of bumper height regulations, but I've seen the 996 GT3 and GT2 are very very low compared to regular 996's so they're probably just to cheap to federalize the shorter version.
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06-24-2005, 02:20 PM
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Originally Posted by texas911
Supposedly because of bumper height regulations, but I've seen the 996 GT3 and GT2 are very very low compared to regular 996's so they're probably just to cheap to federalize the shorter version.
Maybe they just think it is more trouble than it is worth. Customers complaining about ride quality, etc. But they could well offer just the LSD as an option. MB used to do this a long time ago.
How much to have the OEM LSD put in?
06-24-2005, 02:28 PM
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Originally Posted by Christer
I guess a front LSD might be a bit of a waste.
Originally Posted by MMD
Huccum my M3 has it?
It does have it doesn't it?
It does have it doesn't it?
But a 996/997 without LSD can still outhandle an M3 so I don't think you will miss it, the rear mechanical diffrential helps but not an absolute must, and some cars need it more than others.
Originally Posted by mbr129
How much to have the OEM LSD put in?
Porsche offered a mechanical LSD as a factory option on the 996TT now, but not with the 997, unfortunately if you want LSD you can only get it with the -20mm P17 sport suspension.
06-24-2005, 02:52 PM
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Just FYI. The 40th Anniversary model (996) comes with LSD and PSM standard. I'm still trying to figure out how they manage to get both working in sync so perfectly. I can certainly feel a difference exiting and managing a curve at high speed, with the LSD equipped car vs. a PSM only (997). Too bad it is not offered here in the US.
Carlos: Your 997S looks bad a$$. Felicidades!
Cheers.
Carlos: Your 997S looks bad a$$. Felicidades!
Cheers.
06-24-2005, 03:17 PM
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Gracias Fast40th 
The 40th anniv model has indeed rear LSD standard with PSM, it was the first 996 to have LSD and PSM at the same time. The reason on how they were able to make them compatible I believe is in the lock-up rates, if you look at the lock up rates in the cars with PSM they are lower than non-PSM cars, such as the GT3, GT2, or the first year 996C2 (MY1999) which did not come with PSM standard and had a simple traction control and rear LSD as option instead if you wanted (in MY2000 onwards all carreras had PSM). Recalling roughly from memory here, I believe the lock up rates for the non-PMS LSD were 40/60 yet in the PSM cars are 22/27...
Here is a -20mm P17 997S:
The 40th anniv model has indeed rear LSD standard with PSM, it was the first 996 to have LSD and PSM at the same time. The reason on how they were able to make them compatible I believe is in the lock-up rates, if you look at the lock up rates in the cars with PSM they are lower than non-PSM cars, such as the GT3, GT2, or the first year 996C2 (MY1999) which did not come with PSM standard and had a simple traction control and rear LSD as option instead if you wanted (in MY2000 onwards all carreras had PSM). Recalling roughly from memory here, I believe the lock up rates for the non-PMS LSD were 40/60 yet in the PSM cars are 22/27...
Here is a -20mm P17 997S:
06-24-2005, 04:33 PM
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Where to Complain About No Limited Slip
A quick search of sports cars revealed limited slip is standard equipment, or at least an option on all of them. I couldn't find one that didn't have it, EXCEPT Porsche!
Stability control system conflicts is not an issue, because many of these cars with limited slip differentials also have stability control systems. Differential braking is NOT a substitute for a limited slip differential on a sports car either.
Here is a list of cars I found with limited slip differentials (in the US):
BMW Z4 (standard)
Chevrolet Corvette (standard)
Acura NSX (standard)
Honda S2000 (standard)
Dodge Viper(standard)
Nissan 350Z (standard on uplevel models)
even Toyota MR2 has it standard!
Porsche Boxster (NOT AVAILABLE)
Porsche 911 (NOT AVAILABLE)
C'mon Porsche!
It is time for everyone to write in an demand this be STANDARD EQUIPMENT on all Porsche sports cars. There is no excuse for this. It was an option 40 years ago on the 911. I called Porsche Cars of North America, and here is where they said to write with product suggestions (yes, the upper and lower case is exactly as the receptionist described):
Dr. Ing. h. c. F
Porsche AG
Porscheplatz 1
70435 Stuttgart Zuffenhausen
Germany
If any of us gets a response from them, let us know what they say.
Michael
Stability control system conflicts is not an issue, because many of these cars with limited slip differentials also have stability control systems. Differential braking is NOT a substitute for a limited slip differential on a sports car either.
Here is a list of cars I found with limited slip differentials (in the US):
BMW Z4 (standard)
Chevrolet Corvette (standard)
Acura NSX (standard)
Honda S2000 (standard)
Dodge Viper(standard)
Nissan 350Z (standard on uplevel models)
even Toyota MR2 has it standard!
Porsche Boxster (NOT AVAILABLE)
Porsche 911 (NOT AVAILABLE)
C'mon Porsche!
It is time for everyone to write in an demand this be STANDARD EQUIPMENT on all Porsche sports cars. There is no excuse for this. It was an option 40 years ago on the 911. I called Porsche Cars of North America, and here is where they said to write with product suggestions (yes, the upper and lower case is exactly as the receptionist described):
Dr. Ing. h. c. F
Porsche AG
Porscheplatz 1
70435 Stuttgart Zuffenhausen
Germany
If any of us gets a response from them, let us know what they say.
Michael
