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

 

997's have PSM. Only GT2/GT3 have a LSD.

 

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.

 

I guess a front LSD might be a bit of a waste.

 

Anyone know what is Porsche's stance as to why the US does not get this option?

 

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.

 

Huccum my M3 has it?

It does have it doesn't it?

Seems like a great idea for ANY car.

 

Yeah, that's a bunch of crap. There should just be a massive campaign to convince PCNA to bring it here.

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?

 

On the rear wheel drive 997S yesit would be a waste since the front wheels share no torque, but the AWD version may benefit from a front one, the Impreza, Mitsu EVO, and Audi Torsen-type Quattro's have one, but I believe the Lambo's don't.



MMD, the E36-M3 had a mechanical Limited Slip Differential on the rear, the current E46-M3 has now a Viscous-Coupling differential intead.
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.



You can't retrofit the OEM LSD on a 997 that doen't have it from factory, it will conflict with the PSM of the non-LSD car and the system will never allow it.
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.

 

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.

 

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:

 

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

 

Thanks for the explanation Carlos.

 

I'm with you Michael1. You can also add the LSD on the Mini... and even my freaking old Ford Exploder has an optional LSD!