Stupid Question - Can anyone explain what is the purpose for having a limited slip differential (or LSD)? Does the new 997 with PASM has it? What happens to a car if it does not have any differential (or LSD)? Thanks in advance.

 

when you accelerate hard in a tight turn in a car without a limited slip differential - the inside rear wheel spins and wastes power whilst the outside wheel is waiting for the inside to find some grip. this equates to a boring drive because you have to lift off to get some grip instead of flooring it.

a limited slip differential is a differential with a mechanism to limit the amount of wheel spin in that situation. what that means in practice is you can floor it despite the inside wheel losing grip because the slip is limited which means the outside wheel gets some power and wahey.... a nice powerslide.

PASM cars don't come with LSD and apparently you can't have one fitted afterwards - but I can not see any reason why you shouldn't be able to have a LSD fitted to a PASM car to have the best of both worlds.

the Sport package does have the LSD but no PASM.

oh, and if you didn't have a differential at all, the car wouldn't go anywhere! the differential, even without LSD, is a bunch of cogs that gets both driveshafts rotating in the same direction!

 

It seems that the regular 997S with PASM use the "Active Brake Differential" and only the sport suspension with -20mm ride height use the LSD. What is the difference between the Active Brake Differential and LSD? Thanks in advance.

 

The LSD is purely mechanical while the other is electric.

 

Which one is better in terms of stabilizing the car when making turns in a wet/slippery condition?

 

active braking just slightly brakes the particular wheel that spins too fast, whereas an LSD redistributes the power to the wheel with more traction... electronic traction control would probably be better for winter-slippery surface driving even though responsiveness and effectiveness can vary, but LSD's are waaay better for performance driving