Can anyone explain to me the differential system of the 997 Carrera S? It uses a locking rear differential, and not a limited slip differential, correct? What's the difference between a LSD and a differential lock?

Thanks in advance, and pardon my ignorance!

 

I believe that Porsche uses an eDiff on the 997S unless you specifically order an LSD. The eDiff uses the ABS sensors to sense wheel spin and then uses the brake on the wheel that is determined to be spinning.

This is different from a mechanical LSD that locks both rear wheels at the same speed if the speed difference becomes to great between the wheels. This gives much better handling since it allows much more throttle oversteer. The advent of the eDiff has been called the single worst thing to happen for handling of performance cars.

On an interesting side note you will probably see more manufacturers using the programable nature of eDiffs to alter the handling of their cars. The first implementation of this is the new EvoX. It uses an advanced active eDiff to keep the car in a mild state of oversteer in most situations. I keep waiting for someone to start programming eDiffs similar to an ECU flash.

 

The US 997 uses an open diffy with no option available for a LSD. The US 997 controls wheel spin through the ABS system. ROTW cars do have a LSD option with the sport suspension as a no cost option as this will forego PASM. Quaife does make a locking diffy for the 997 and it runs about $1600 and probably another couple of grand to have it installed.

Dave

 

I have the Quaife in mine, but haven't been back in the States to drive it since. Gimme one month and I'll tell you what I think. Go to Dan at Vivid. He got it out the next day. I'm totally gonna support that dude. Anyway, I think Rick (58speedstr) has his in and drives the ***** off of it. Maybe he can tell you what he thinks.

 

It's an option on the 09 997. Option code: 220 for the LSD by it self or with the PASM Sport it's option code: P17 ( lowers car by 20 mm & stiffer than regular PASM ). For Carrera 3.6 you must have 19's .

 

Correct, except the quote of 20mm drop is for cars without PASM, I believe it's only 10mm for cars with PASM as cars with PASM sit 10mm lower than cars without.

Dave

 

The order guide says -20 mm for PASM sport with LSD and -10 mm for regular PASM.

 

That's what I said..it's 10mm lower than cars with just PASM. If you get PASM sport it's not 20mm lower than a car that already has PASM.

Dave

 

It's a shame the US cars don't have the LSD option

 

They do have thee LSD option for 2009. Also there is a new option for -20mm with a sport PASM. There is also the regular PASM at -10mm.

 

Thanks so much, Salespunk and Dave.

 

If you are waiting for a 09 definitely get the LSD, this will help alot with the axle hop as well these cars are notorious for.

Dave

 

Will it only help in the corners or will it also help through straight acceleration?

 

Both, you can leave the line harder...

 

Sweet