LSD

[OZ930]

I am considering installing a Limited Slip Diff in my 930

 

I am after opinions and advice on:

 

1. is it worthwhile for street/road use

 

2. what type of diff, i.e. clutch type (ZF) or helical (Quaife)

 

3. Brands, ZF, Quaife, OBX Racing, etc

 

Thanks

 

 

 

 

 

 

 

 

 

 

[Buchanan Automotive]

Hi OZ930,

LSD's are one of the best upgrades for any car. Much more so for a track orientated car but none the less you will gain quite a lot of car control even for street use. Over the year we have used a few manufactures of LSD, Modena, Guards Transmission, Quaife etc. All have exceptional products. GT seems to be the standout for us for quality and price. In their clutch range you even get an option of 2 ramp rates (locking percentages) for the clutch type LSD.

 

There are benefits and downsides of both Clutch and Torsen

 

With a Clutch type LSD the car will have a little more initial understeer, As the clutch is engaging both rear wheels to drive the car will want to drive straight. Cornering is light and day, No more will you have the inside wheel spinning and loosing speed coming out of a corner. But thats not the only benefit of a Clutch type LSD. under braking the car will become much more stable, Trail braking becomes easier and you can push the car a lot further into a corner without the rear end forcing itself around on you. A small amount inside wheel slip will happen on slow high angle corners(such as U turns). For those who like to power slide there cars LSD's are a must

 

The Torsen Type LSD will act almost like an open diff under normal driving patterns, No noise or chatter in tight turns. Under acceleration(out of a corner or hard launch) you can get up to 100% locking factor which is as good as traction as you are going to get. The downside is that under deceleration there is no locking and the car will act like an open diff. trail braking will then become more difficult just like an open diff and the rear end will become loose.

 

In My eyes I prefer the clutch options, i use one in our 944 turbo which is driven every day to work and is one of the quickest cars in the Porsche Club supersprints. The Torsen is a perfect motokhana LSD as you can get faster rear end rotation around witches hats, and still a great road option, particularly considering the price of Torsen units.

 

Hope this helps

Regards

Sean

[OZ930]

Thankyou Sean, 

 

Have you heard of the Wavetrac diff centre?

 

Does/would the Wavetrac diff improve the issues of the Torsen diff during deceleration ?

 

http://wavetrac.net/technical.htm

 

I suppose the only other issue would be price.

 

All information helps thanks Sean

 

Cheers Brian

 

 

 

To the Moderators:  I looked for this subject prior to posting but missed the Topic "LSDs".  If you wish to merge this topic please do so.

[randall]

Wavetrac does not lock under deceleration, they claim that their technology fixes another issue with torsen style diff known as "no load" condition which is when one wheel has zero grip a typical torsen diff will not lock and transfer power to the other wheel.

[OZ930]

Thankyou randall,

 

interesting

 

sounds like the plate clutch type LSD is the way to go

[OZ930]

I wrote asking if the Wavetrac maintained drive during deceleration and also the pricing.  This the reply.

 

Brian, we do have these differentials available, part # for your car should
be 40.309.150WK, they are $1395.00 each and yes, they do bias power
effectively on acceleration and deceleration unlike other gear driven diffs
on the market. Unlike other diffs which stop working under zero load or
close to zero load conditions, our still works under such conditions, and
allows you to have the car handle that much more effectively.

[SteamWolf]

Honestly on a road car I wouldn't bother unless you are lighting up one wheel all the time.

[OZ930]

Honestly on a road car I wouldn't bother unless you are lighting up one wheel all the time.

 

yes I know, that was my first question......but the research and information is great for future reference.

 

and we can't have Uncle having all the fun 

[TINGY]

Was'nt that stuff all the rage years ago................just sayin'!

[Caver]

Yep I was right....no drugs in here......

[OZ930]

Sorry Caver, how about a Panadol ?

[randall]

I wrote asking if the Wavetrac maintained drive during deceleration and also the pricing.  This the reply.

 

Brian, we do have these differentials available, part # for your car should

be 40.309.150WK, they are $1395.00 each and yes, they do bias power

effectively on acceleration and deceleration unlike other gear driven diffs

on the market. Unlike other diffs which stop working under zero load or

close to zero load conditions, our still works under such conditions, and

allows you to have the car handle that much more effectively.

 

Interesting that they do not mention specifically the fact that diff locks on deceleration on their website, one would think they would advertise this as it would be a major advantage over other torque biasing diffs available. When I looked into it a while ago I recall reading on few different forums that people were not convinced the Wavetrac indeed does this effectively. 

[randall]

Some positive comments on Wavetrac from a 911 owner:

 

 

Even though this seems to be a year old thread, I have experience with Wavetrac in 2 applications. I have an '85 911 track/street car with a modified Euro 3.2L, coilovers and a '74 911S 7:31 short gear box. It's a very happy puppy with great scoot and handling. I love the Wavetrack, it puts down the power on short technical road courses with numerous slow tight turns and elevation changes in my region and the cars behavior under decel, braking and trail braking is exemplary leading me to believe in the claimed friction on deceleration.

From this thread: http://forums.pelicanparts.com/porsche-911-technical-forum/588591-wavetrac-lsd-2.html

[randall]

And this:

 

 

 

Along the lines of what Steve said, I have recently sold a couple of LSDs to people who had tried the Wavetrac and didn't like it. What has been reported to me is that it does not lock up under braking in way that it has been advertised and that in their experience it was similiar to a TBD. I've never driven one or handled one, and am only passing on what I was told by two different customers I talked to.

 

 

 

 

i have a wavetrac tbd and experience too much wiggle under hard braking. have had it for one track season. i am moving to guard lsd. so, i will have a slightly used wavetrac tbd for sale if anyone is interested.

 

 From this thread: http://forums.rennlist.com/rennforums/993-forum/683066-diff-between-a-tbd-and-a-lsd-2.html