PSD what to do with it? want LSD
11-15-2014, 05:04 AM
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PSD what to do with it? want LSD
Hi guys,
I’ve got a question. I have a 87 S4 with manual gearbox, the car drives perfect, but I would like to add a LSD.
Out of my “stash” of spare gearboxes I have one from a GT with a PSD diff, can I do something with this diff?
I do not have the hydraulic cylinder with it, nor any computer or pump.
I know you can put in a bolt so it has a fixed amount of locking, but this is not ideal…
Also I found a thread about an aftermarket controller for the PSD but this stranded I guess?
So what can I do with it? Or should I just keep looking for an LSD (in Europe (The Netherlands..))
Or is there maybe somebody who wants to trade? PSD for LSD?
Thanks in advance,
Best regards
Sander Baas
I’ve got a question. I have a 87 S4 with manual gearbox, the car drives perfect, but I would like to add a LSD.
Out of my “stash” of spare gearboxes I have one from a GT with a PSD diff, can I do something with this diff?
I do not have the hydraulic cylinder with it, nor any computer or pump.
I know you can put in a bolt so it has a fixed amount of locking, but this is not ideal…
Also I found a thread about an aftermarket controller for the PSD but this stranded I guess?
So what can I do with it? Or should I just keep looking for an LSD (in Europe (The Netherlands..))
Or is there maybe somebody who wants to trade? PSD for LSD?
Thanks in advance,
Best regards
Sander Baas
11-15-2014, 06:24 AM
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Without the controller and other associated electronics the PSD is not a very good substitute for a LSD in my opinion.
I would suggest you keep looking for a LSD.
I would suggest you keep looking for a LSD.
11-17-2014, 10:05 PM
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If I had a PSD and wanted it to work like an LSD, I'd look at building an external spring housing similar to the way the factory timing belt tensioner works. It would have a jack bolt and a stack of Belleville washers, and a pushrod from the other side of the stack to apply pressure to the PSD clutch pack. That way it would self-adjust some for temperature changes.
The biggest 'problem' I see for using a simple bolt with no spring is that most folks think a limited-slip should really be a no-slip spool, and put a lot of pressure on the clutch pack. Reality is that breakaway greater than maybe 40 lbs/ft causes chatter and is pretty much undriveable on the street. PSD was Porsche's answer to that, applying pressure to the clutches only when serious slip was detected. That way the disks last a long time, and normal driveability isn't compromised.
If there's a way to get the PSD working, I'd be looking at that option before I started looking for a rebuildable LSD for the downgrade/conversion. My too sense anyway.
The biggest 'problem' I see for using a simple bolt with no spring is that most folks think a limited-slip should really be a no-slip spool, and put a lot of pressure on the clutch pack. Reality is that breakaway greater than maybe 40 lbs/ft causes chatter and is pretty much undriveable on the street. PSD was Porsche's answer to that, applying pressure to the clutches only when serious slip was detected. That way the disks last a long time, and normal driveability isn't compromised.
If there's a way to get the PSD working, I'd be looking at that option before I started looking for a rebuildable LSD for the downgrade/conversion. My too sense anyway.
