garrett376

Ok C4 techies... got a question for ya'!

I was curious about the "active" differentials used in the G64 tranny.

Regarding the lateral differential: when the PDAS is not activated, meaning the hydraulic lock is not activated, is it acting like an LSD differential? If so, what percentage lock is the differentia when the PDAS has no pressure going to the differential lock?

Then for the longitudinal lock, I assume that the torque split is 39/61 normally, then increased from there. Correct?

So when guys on the track disconnect the PDAS, I am curious what the differentials, lateral and longitudinal, sit at for a baseline setting. By the way, do all you guys who track the C4 unplug the PDAS module??

Thanks for the input! This is very interesting, and inspired by the C4 RS post earlier with its interior pics showing the manually adjusted dual differentials - very cool!

Adrian

When the lateral lock is not activated the rear differential acts as a standard open differential. If the PDAS is disconnected then it remains a standard open differential the whole time. It only becomes a LSD with the PDAS activated with the differential lock providing the locking action.
The same applies to the power transfer unit and the drive spilt will remain 31/69 at all times with the PDAS disconnected.
The C4 RS is fitted with the Paris-Dakar AWD transmission (959 Paris-Dakar) which bears no resemblance at all to the 964 C4 AWD system apart from its AWD.
The only 964 C4 actually set up and used in racing (Quattro Team) in France was fitted with the 961 AWD racing transmission.
Ciao,
Adrian
964C4
GT-2