Millemiglia

At a recent trackday, I got a ride with one of the instructors who drove a lightly modified 964 C4.
The car had H&R gewindefahrwerk, Michelin Pilot Sport Cup, thicker rear stabiliser and he had disabled PDAS system.

And boy, did that car drive!

It had none of the understeer I experience on the track with my C4, of course my car drove on Yokohama AVS sport and is a lot heavier (a cab remember..)
but still!

So my question, is it possible to disable PDAS at or before a trackday and the enable it for regular road use or is it altogether not possible?

The dream scenario would be a switch inside the cockpit from where you could disable/enable it as requested...

garrett376

I race my car with the PDAS functional and I have no problem with understeer - none! I think you will find that it is suspension setup that makes the difference - but if you want to try it, just unplug the control module in the trunk on the left side.

I've raced with and without it engaged (because of a fault that disabled it halfway through a race) - I was faster with PDAS helping me since you don't waste power spinning your wheels that have less traction (usually inside rear wheel).

You will be fast in a C4 if you have it set up right to help dial out the inherent chassis understeer; throttle on understeer can be controlled by learning when and how to apply the throttle so you don't "plow" out of corners. Bottom line - brake later, trail brake into corners to rotate the car, and nail the throttle!

Millemiglia

Would that be the left side, looking from the driver's seat?
Are you talking about the module under the plastic cover by the brake hydralic boost pressure accumulator?
By temporarilly removing it, will that cause a lot of errorcodes in the system?
and if so, can those be removed by a dme reset?

Adrian

No right side front forward looking from the driver's seat. The control unit is not covered in the 964. Big mistake, but there you have it.
Do NOT touch the ABS hydraulic unit or the hydraulic brake boost system.
The DME has nothing to do with the PDAS/ABS.
There is no viable switching system to just disable the PDAS. It is integrated and interlocked with the ABS as part of the design.
When you pull the connector you also remove the ABS. You will get two warning lights as well. Cover with black tape so they do not distract you.
The C4 drives significantly better in my opinion with the PDAS disconnected on summer tyres. In winter it is worth its weight in gold as long as you are using winter tyres.
Ciao,
Adrian.

Millemiglia

Adrian, just to be on the safe side, is this the one?

btw. I borrowed the picture from a technical document on the AWD and PDAS
from your website, http://www.adrianstreather.com/docs/...overviewR2.pdf

photo by Yasutoshi Kikuchi

garrett376

That writing in the image looks like it's from a horror film!!

Yes, that is the PDAS control unit that you have circled - unplug that big plug to disable the PDAS and ABS systems.

Millemiglia

Point taken.
Don't quit your dayjob unless it is as an graphics designer...

Thanks a lot guys, I will try that at the next trackday I attend.

garrett376

And please write back with your impressions - I think you'll prefer the PDAS activated... but let us know!

David P

I agree with Garrett, set the car up properly and trail brake it will make all the difference.

Last Sunday I was at Phillip Island (a race track in Oz) with a friend with a 964 C2, with a similar set up to my C4, and I was consitently a few seconds a lap quicker. I'm sure that's partly due to the PDAS working as I came out of the tight 2nd gear corners.

DavidP