Hi there;


I'm still fighting my transmission issues. The transmission is blown. When it's all settled, I'll probably say more.

The car is in a trustworthy shop in Philadelphia. It's getting a transmission rebuild. I need to decide if I want a limited slip differential added. I expect I'm going to just go for it, but LSD is pretty much still hypothetical to me, so I'm curious;

My car is an 1989, with an automatic. Mildly worked.




Is there any reason NOT TO add it? Any downsides to having it?

Does anyone have one for sale?

These cars were pretty expensive when new. All things considred, why didn't Porsche just include it with the car???

If you didn't know whether or not your car had it, would it be easy to tell?



I've read all about it. I know what it does, and when. Still, I never was in a vehicle with it. I know what it is, and how it works. I'm just curious.

I believe it was available as an option over what appears to be at least most of the years the 928 series was manufactured. What percentage of cars had it?

Anyway, it'll add time and money to the car, but the car is a keeper and I am hoping for opinions.

Thanks so much...

 

When you give it too much gas in a corner do you prefer that the inside rear wheel spins or that both wheels spin and the car oversteers /fishtails ? That it what it boils down to. Pure racing the slip puts down more power. On a rainy day a slip can break the rear end loose much easier and your rear end passes your front end.

 

Ahhhhhhhhhhh. So it wasn't a standard feature as it has the potential to cause problems, though controllable by an experienced driver? A "regular" differential essentially limits the power that can be applied, but won't scare the hell out of a "typical" driver?

 

If you want more grip during acceleration and braking do it!

 

Nick,
I have one for sale - let me know.
Sorry to hear you are still having problems.
Roger

 

Absolutely! In my opinion, it's one of the most desriable options (220) on a 928!

 

Yeah, I'd do it. On an outing with the Porsche club (mostly newer 911's)I was in the top pack on great twisty roads glad I had it on that speed run!

Mine came w/option 220

'89 S4 GP/White Black LSD, RMB
'76 912E Silver/Black

 

And how does it help with braking on an ABS equipped car ? especially when both rear brakes are on the same circuit.

 

I think the yes/no as an option was price, would the customer pay for it, and many times the answer was no, especially I would guess with 80% AT.

Now its highly desired for the standard Porsche reason, what is the best, I want that.

One of my cars will have one, and the other won't.

 

I'm kind of curious: Just how much was the option to add it to these cars, when they were new???

What percentage of cars came with it, roughly?

 

Dunno if Id put it like that...

Its just an option, a HIGHLY desired one.

 

The typical buyer of a new 928 could have cared less about a limited slip which is why they were not that common. The GT had it as standard until PDS in 1990 was fitted to all 928s. So for the OP if you are not spinning one wheel in your driving no need to add a slip but if you do get one be prepared to rebuild it before installing it as the internasl wear out over time.
Every time you turn a tight corner at any speed one wheel turns far faster than the other and the friction discs MUST slip, slipping is wearing.

 

Realistically, by the time Porsche made the limited slips for the late cars, they were mostly made for snow use, where one wheel could be subjected to slipping and the car not moving.

The lock-up percentage is so low that any "performance" advantage is probably low or completely moot.

That being said, if I were you, and had the opportunity to put one in, I probably would do it....what Danglerb says pretty much hits the nail squarely on the head.

 

I have LSD on my 928, can't imagine not having it. But then, besides spinning the tires and doing a little fun fishtailing now and then, I also occasionally drive the 928 in snow. Now, my Challenger also has LSD, called Suregrip, an excellent marketing description, and I can't imagine having an open rear end in that car either. Let's see, the Suburban has LSD also, called Positraction. Can't even imagine taking that 4x4 into the mountains without it. Nope, in my mind you can't beat a locking rear end (comments welcome). GO FOR IT!

 

From '87 to '89 in the U.S., roughly 42.69%.


$791 option in 1988.