Eric_Oz_S2

Thinking about getting a LSD for my S2. I get a lot of wheel spin exiting tight corners on the track, and although it is somewhat entertaining, I wouldn't mind some more push out of corners.

Where is the best place to buy a Quaiffe (or Guard?) LSD. Cheapest I have found so far is £775 + shipping from the UK for a Quaiffe. What would the installation cost (assuming trans delivered to shop) be, and would you need to put new carrier AND pinion bearings in? Anyone done this themselves.

333pg333

Funnily enough some of these are actually made in Melbourne, but it's probably cheaper to buy one from Guards US where they're shipped than out of Melbourne.
Having said that, contact JET951. He might have one left I think??

gt37vgt

there is one for sale on the PCV web page for 600 au$ and your up for a few hundred to have a gearbox guy install it and set the back lash ,

TonyG

You don't want a Quaiffe for the track. They act like open differentials under braking and/or if you lift a wheel.

You want a clutch pack style LSD (like the Guard GT).

TonyG

disasterman

Installation requires serious experience along with the proper shims. If not installed properly it will get destroyed. I paid around 700 to have it installed by a pro Porsche shop that had pleny of 944 trans experience. I did the in and out with my mechanic on my home lift.

951_RS

Yeah, quaife is good for the street and sparingly used on track.
It's safer as it's a 1 way lsd, but I'd probably shoot for a 1.5 and maybe 2 way if you're experienced.

Eric_Oz_S2

So is the standard (40% locking) Porsche LSD option better than the Quaiffe? I thought the Guard was also a torque sensing diff. Is there a web site that explains the benefit of the Guard?

gt37vgt

torisin diffs are more civilized on the street more civilized in the rain last longer don't need the clutches serviced . and are fine on the track until you are going pretty hard ..
it all seems a bit " monky see monky do" some one please tell me exacly what the issue with and open diff under brakes is ??
does the car lift over steer ?

TonyG

It's far from a case of "monkey see, monkey do".

Cars are much slower around a race track with an open differential because the rear end of the car wants to rotate when you lift, wants to come around if you trail brake hard, not to mention the inability to literally throw the car into a corner off throttle without spinning.

When you keep the rear tires spinning at the same rpm, all of the above is substantially reduced. That means you can go into a corner much deeper, much faster, and as a result carry more speed out of the corner.

This is common knowledge.

In fact, the very reason that a lot of "spec" class racing prohibits the use of a LSD, is to make the driver have to work harder and slow down the cars (cost is a secondary benefit).


The fact that a Quaiff or Torsion type differential acts like an open differential under deceleration is what makes horrible for the race track. Additionally, if that were not bad enough, if you lift an inside tire accelerating, it again acts like an open differential.

Honestly, I just can't see any reason ever spend the money to use one unless it was in some sort American V8 street car.


TonyG

TonyG

Yes the standard Porsche LSD would be a much better option than a Quaiffe style on the track.

If you go to GuardTransmissions.com under Latest News, there is some good reading there.

Guard makes two styles of differentials. The "torque sensing" style, aka Quaiffe or Torsen or Torsen Gleson, and the conventional clutch pack style.

TonyG

gt37vgt

so Tony is that a first hand account of you trying to drive an open diff 944 ??
When you diff pack starts to where out do you start to get these problems while braking ?
or does it start to spin a wheel and you pull it out and fix it ?

TonyG

Yes not only with a 944 but also with several 911's and and a several Boxter/Boxter spec cars.

I've got 2 years of track time on my current Guard Diff (that's in my V8 951) and there is no noticeable wear with respect to the way it handles so I can't comment on what it feels like it when it wears out. But since it's a clutch style LSD, it's going to exhibit the exact same wear characteristics that a factory LSD would.

Anyway... there's no two ways about it... a LSD car will always beat a non-LSD/Quaiffe car (apples to apples).

TonyG

gt37vgt

i have no doubt that cars with more rear weight 911's etc need the some diff lock while braking ..
So far i have just got not real first hand accounts of 944's misbehaving under brakes due to there open diffs or torsin diffs and that is what I'm looking for .
I just wont accept "torsin diffs are junk" without some people giving them both a good chance in a 944
also i think abs non abs is a factor surly these problems under brakes would be more pronounced on non abs cars ..
.

samluke

Tony's right, there is a lot of information on the internet to explain what works in which conditions and why.

The Porsche clutch pack LSD with 40% can be tweaked a little to change the locking. The beauty of the GT is you can change the locking ratio's both under braking and acceleration to suit personal preference/driving styles. That's tough to do cost effectively in a Porsche LSD.

TonyG

ABS has zero to do with it.

And it's not a misbehaving thing. It's the same for all RWD cars.

On a track you need that rear wheel lockup (wheel to wheel) at the limit of adhesion to control the back end of the car. On the street, how often are you at the limit of adhesion? Never.. That said I guess a Torsen would be good for a purely street car or a car that sees lots of rain/snow, etc... But on the track, the LSD rules. And the asymmetrical LSD blows the conventional symmetrical LSD out of the water on the track because you can have a lot of diff lock under deceleration/braking and a lot less under acceleration (which eliminates the LSD induced push). You really get the best of both worlds.


TonyG