Need Info about PASM and Limited slip
#1
Need Info about PASM and Limited slip
I'm in the market for a used 981. I am an autocrosser, but am confused about availability of limited slip differential, which is usually important to be competitive. On new cars the Porsche website has PVT with mechanically locking differential, but it only can be ordered with PASM. But it appears that PASM can be ordered without PVT.
For the 981, was this the same?
Is PVT, which I understand is a brake torque vectoring system, the same as a mechanically locking differential? Or are they separate?
I.E., does a used 981 with PVT therefore also have a mechanically locking differential ?
Finally, does the "S" or "GTS" Cayman or Boxster have any of this standard? Or did all 3 (base, S, GTS) come standard with an open differential ? (hard to believe....)
I saw that there was a 718T version in 2021 or around there that had both PASM and PVT standard, wondering if there was any equivalent of this with 981.....?
Thanks for your help.
For the 981, was this the same?
Is PVT, which I understand is a brake torque vectoring system, the same as a mechanically locking differential? Or are they separate?
I.E., does a used 981 with PVT therefore also have a mechanically locking differential ?
Finally, does the "S" or "GTS" Cayman or Boxster have any of this standard? Or did all 3 (base, S, GTS) come standard with an open differential ? (hard to believe....)
I saw that there was a 718T version in 2021 or around there that had both PASM and PVT standard, wondering if there was any equivalent of this with 981.....?
Thanks for your help.
#2
The GTS has it all standard.
The base or the S can be optioned with PASM. And if it has PASM, it can also have PTV and the factory LSD.
You can also have PTV with the X73 suspension. Seems fairly common on GTS as the X73 was a free choice if you didn’t want PASM.
The base or the S can be optioned with PASM. And if it has PASM, it can also have PTV and the factory LSD.
You can also have PTV with the X73 suspension. Seems fairly common on GTS as the X73 was a free choice if you didn’t want PASM.
#3
Instructor
The factory LSD option is called PTV for Porsche Torque Vectoring. It is a mechanical LSD but is augmented by intervention by the braking system. PTV is not standard on the GTS - it had to be specifically ordered. The fixed, analog sport suspension (X73) was only available as an option on the GTS. PTV was available with either the PASM or X73 suspension options.
#4
On the 981 everything is seperate options. It depends on exactly what you're trying to do with the car, but I've been around a few different option combos and autocrossed them extensively. IMO you don't want PTV or PASM, because the electronics get in the way more than the physical parts help. If you're allowed to disable the software side of PTV, then sure. And a DSC controller can fix most of the shortcomings of the PASM system but X73 sport suspension is still better. Also keep in mind that it's a mid engine car with not a tremendous amount of power/torque, it doesn't really need a LSD, and the stock unit is only like 20% lock and zero preload. All it's doing is controlling a tiny bit of inside wheel spin mid corner, it doesn't really influence handling.
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Last edited by Cosmo Kramer; 05-13-2024 at 06:49 PM.