I'm thinking about hooking up the PSD system on my car, can anybody tell me how much the actual pump assembly weighs? Also for those who have PSD and have used them on the track or aggresively elsewhere what has been your driving experiences?

Thanks Greg

 

Greg,
Don't know how much the pump system weighs, however, full description with schemetics, drawing and cheching procedures are contained in Jim's Technical CDs.

If you have not got these they are available in Australia through Eddy Sain in Adelaide.

PSD if fitted to my S4 and works a treat.

Tails 1990 928 S4 Auto

 

The PSD works well when it works, but I think it is more adapted for street than track use. It can be pretty rough when it kicks in and I think a LSD will do just as good of a job in most situations and work better on the track.

 

Hey Anders....How was your trip to NorCal?? Did you have an opportunity to hook up with the NorCal Crowd??

 

Hi Greg,

weight is 6,25 Kg without brake-fluid in the main container.
No driving experince yet....

Br/Peter

 

Anything can be done, but adding a stock PSD to a car that was not made for it would be very difficult and costly. The PSD system is tied into ABS and I believe has other sensors (or shares them) with other systems not standard on previous models. I believe there is some sort of G-force / roll input to the PSD that also controls it's actions. Could be more than it's worth.

 

what about converting the PSD to LSD or a fixed slip ratio?

 

Hi sweanders when you say it kicks in, it can be a bit rough, from what I read from Porsche it is supposed to be a settling influence, not an abrupt one, so there is one flag down, Thanks for your input Tails too. Thanks for the weight Peter. That is helpful in making up my mind, weight will be a issue on this car. Also I must have some sort of traction control system, even with the power it has now an open diff is a nightmare.

Mike N you are quite correct, I'm used to doing big jobs, I will probably buy a wrecked GT or GTS from Japan or Honkers and do a change over, I already have the gearbox and the abs sensors fitted to the car with the late model driveshafts, this moment has been coming for some time. Also I will EVENTUALLY get my engine project done, I want to run electronic throttle bodies like the m5, the Motec can run these, you can tune in how much throttle you want at different accelerator settings.

DrNick I was thinking about the bolt setup for the PSD, this is what Mark Anderson runs I believe, but for the street you would need to back it off, otherwise I would have though that it will just wear it out, I want something that a is a bit smarter too. 100% locking on take off, remember I only have 285 or maybe later 295 rear tires. Also from what I read the Ferarria effect or something like that, it countered by the PSD. I like this as then I can do away with the movement in the rear suspension that causes toe changes on acceleration and braking.

Remember that is what Mclaren didn't want happening with the F1 roadcar, they found they was quite a bit of movement in the 928, a third of a degree I believe, the Mclarens movement is barely registrable. This aspect would be one thing that gives live rear axle cars their advantage in takeoffs I think. Please keep the reponses coming.

Also I spoke to a fellow selling Quaife torque biasing diffs, he said you dont want one of those, what you want is something that will lock 100% on power 50% on trailing throttle, this guy did build racecars, had some exotic stuff in his workshop too, like a 962. That's what got me thinking the PSD mightn't be too bad after all.

Cheers Greg

 

greg, ive just been to see a breakers yard near manchester this afternoon where they have a fewGTS cars and engines... they do want serious money for them though i did hear they will discount the price if you buy two of them!

 

so what does the 'bolt setup' achieve, is it equivalent to the LSD? i definitely like the LSD in my 88, can feel it all the time in the wet.

 

"Bolt setup" would have to be same as LSD I think.

Anders, can you elaborate what you mean by "pretty rough when it kicks in". All I have heard is complain about it going of at 30 kph when accelerating straight. Other than that it does it's job quietly.

In this modern age of computer this and computer that it's shouldn't be too difficult to hack PSD control units output on all different inputs. Next step would be to change programing to suit ones needs. All we need is someone like John Speake to buy '90 or younger model and wait when custom chips are available.

 

I like you thoughts Errka, that's where I'm coming from too.

 

drnick - so what does the 'bolt setup' achieve, is it equivalent to the LSD?

Vilhuer - "Bolt setup" would have to be same as LSD I think.

I have an 88 track car with a 91 auto tranny that has the "bolt setup." I can tell you that I have been very impressed with the performance and adjustability of this set up. If you like the LSD (45%), imagine an LSD that you can adjust the lock ratio to fit the track or your specific driving taste (0% -100%). Of course you have to be knowledgeable in how more or less lock can help or hurt you in any given driving or track situation.

This car was originally shaaark89 (Tom F.'s) car. Maybe he will contribute his experience with this setup on the track.

I am currently in the middle of the auto to manual conversion fun.

 

What I meant is that I don't really like the feel of something changing the cars behaviour, PSD saved me a couple of times but I don't really see the point in having such an advance system. And it did fail me a couple of times during a slalom event and I got the big flashing warning and the whole car jerked pretty badly when it was disabled.

 

so PSD with locking bolt might actualy be superior to plain LSD in that it can be ajusted and for non race applications reliability should be equivalent!