Just wanted some input. My 95-993 is in the shop due to poor handling which turned out to rear end needs rebuilding or replacement.
My options from the shop is to rebuild original or to replace with a Quaife. I dont currently track the car, may in future but probably not. The extra expense $600-$800, when I bought the car (our first porsche) about a year and a half ago the prior owner seemed to put alot of right mods. bilstein, eibach euro ride hgt., rsr flywhl clutch, exaust, airbox, chip, short shift etc.
Should there be any reason not to upgrade to this diff.? even just for street use. I plan on keeping this car long term so I want to do everything the right way. Also a side note I am also powdercoating the wheels satin black, cant wait to see how it will turn out.
Thanks for any info.
Jeff

 

A lot of listers have used the Guard lsd on their 993s. I am having one installed as we speak along with lwf and RS clutch, so can not yet provide first-hand experience.

 

For a street car I would skip the limited slip. I drive pretty hard and seldom ever get wheelspin on the street. Since the limited slip typically increases the understeer characteristics (unless you use springs/swaybars/alignment to adjust the balance) you may find that it's not a good mod for a street car driven in dry conditions. If the car is tracked or autocrossed, then I would go for it and just live with the tradeoff in handling balance.

The question for me is how/why the worn non-lsd rear diff is affecting the handling???? Seems a bit fishy without knowing more about the symptoms.

Um, just reread your post. Does you car currently have a worn out lsd and you are wondering whether to rebuild it or replace it? Or does it have a non-lsd?

 

Yes it does have a worn lsd.(sorry should have put a few more details) and the option was we could rebuild the original lsd or replace with the quaife. I have tracked my e-30 m-3 a few times but really not sure if I will the 993.
The rear end was worn out to the point where the diff. was slipping side to side and the handling was scary even in straight line.

 

If it's just for street use, don't bother with the LSD at all since you'll never notice it. You can have Guards rebuild your current LSD for around $500 with improved friction disks (do a search for more info). That'll be fine for the track, but won't last as long as his $2300 lsd that the hardcore track junkies install.

Very few, if any, have installed Quaife. I've forgotten most of my LSD knowledge, but quaife LSDs don't lock on decel, right? If that's the case I'd rule it out immediately since that's half the benefit -- braking stability.

 

Ahh, okay. If it were me I would rebuild the existing unit rather than "upgrade" since it is primarily a street car and any potential track duty will likely be a casual track day or DE.

Also, I think I read that the original units did not last long but once rebuilt they were pretty robust.

 

I guess that would depend on how you drive..

I installed a Gaurd LSD after my stock diff started to break off teeth- I'd say that the difference wasn't just noticeable, it was incredible.. On a straight line, I can't tell the difference, but in a corner, when you're matting the gas, it's an entirely different car. The power to the street is like night and day, well, not really the power, but the control the car now has.. it was much more of a handling improvement, then say adding the PSS9's..

Coleman.

 

I am a little uneasy that the diff is the root of your handling issues, straight line et al. I would think there is something else out of whack.

Did these symptoms just start one day, or a gradual change? The 993's are quite sensitive to tire condition and type. Also sensitive to alignment settings, rear kinematic toe settings.

Certainly, rebuild your orginal LSD. Use Guard Transmission -- they offer plasma sprayed clutch disks that will last much much longer. GT are quite quick on their turn-around and reasonably priced.

 

As has been said, have GT transmissions rebuild the stock lsd. I seriously doubt that the diff was the root cause of you evil handling.

Evil handling can be from something as simple as tire pressure to worn joints and bent arms. Have someone that knows these cars go through it.

 

First off, thanks for the replys. It has been over time the handling got worse i could feel it in the seat like the azz end was wobbling. On say a long sweeping turn it would want to drift around, very uneasy. As stated prior this is my first p-car I am used to german sports sedan's s-4, m-5, m-3 so I first thought with the talk on how these cars handle I would get used to it but, not.
the shop my car is at is reputible p-car only club recommended shop. He told me (please bear with the terms) the diff. wears down to the point that theres slope in the rear end and it was shifting side to side. We checked all other possibilities like alignment, tire press., wear, and anything else it could have been.
The docs I have from prior owners shows a lsd was part of the mods. done over the years. I was just curious on my option to go with the quaife vs. rebuild. Also i was told the quaife does also lock on decell.
Sorry to be so long winded, I guess I sirred up more ? than I thoughjt and just wanted to clarify a few things. Jeff

 

Broken drop links, worn suspension?

 

Jeff,

What's your budget? For a road-going 993, I don't think LSD matters all that much, other than for street cred and for better wet weather traction, because there's so much weight back there. Is it better to have LSD for the street? Absolutely. If your budget can accommodate it and if you plan in keeeping it for a while, have Guards put in new plates. If your wallet is thin, leave it alone; you can always have it re-done at a later date if it's that important to you. I certainly wouldn't pitch it for a Quaife, which I do have in both Miatas.

 

Hi Jeff,

I recently had my LSD rebuilt by Guard. They were able to increase it from a 2 plate to 4 plate. The price can vary but if I recall, it's normally about $550. Of course, you'll also have to pay your shop to remove it, ship it to Guard and then reinstall it. I track mine quite a bit and am very pleased w/ the result.

Also, just like a doctor that says you have an illness requiring surgery, you should get a second opinion. For sure I'd call Jae Lee at Mirage Intl (no affiliation, just a satisfied customer) and describe your symptoms and see if it's likely to be the LSD, or something else - www.mirageintl.com

I'm certainly no expert, but as others here have alluded to, it seems odd that the cause of your trouble is from a worn LSD. Good luck.

 

I agree w/ the first part lsd on the street just isn't that important

I've got to diagree w/ the last part depending of course on usage. When both drive whels are on equally slick surfaces the tendancy of the car will be to slue to the right due to the massive angular momentum of both wheels spinnng at the same time. This is most noticeable on ice and snow but a a wet& oily surface will also cause it and is also a big reason the manufacturers are reluctant to use an effective lsd on all road cars(cost too of course).

lsd is great for getting you unstuck, and putting down torque usefully during a dry corner exit and in heavy braking into a corner but not so swell going up a slick icy hill w/o good traction at at least one wheel, add road crown and it is even worse.