rear differential
 

what kinda of rear differential does the box have.. or does it change year to year... i have a 2001 non s

All Boxsters before 2009 had open diffs. In 2009+ there is an option for a mechanical LSD. the new Boxster Spyder has an LSD standard.

what is preferable... LSD or open?

Performance-oriented drivers prefer LSDs because they vastly reduce unwanted wheelspin, in turn making the car put down the power much more effectively, especially in turns. An LSD is also much better at dealing with low-grip road situations, such as when driving through snow and slush.

The downside to an LSD is in some situations, it can make the car a bit of a handful. This is because when only one wheel breaks free, not much typically happens other than a smokeshow and some squealing (which is what my Boxster tends to do). When both break free, you need to be ready to deal the back end losing grip. Not that oversteer won't happen with an open diff, it's just that when it does happen with an LSD, you're usually going faster, and that makes everything more interesting. (taken from my experience with my torsen LSD-equipped IS300 v. non-LSD versions).

I see no reason for a LSD on the street unless you're trying to drag race, on the track or autocross course things may be different. Are you currently having wheel-spin issues?
Steve

no i was just curious as to what my boxster has and why it has it. seems to me if the LSD is superiour it should have been put on a boxster sooner... or at least as an option sooner

Cost, marketability, and making sure that the 911 is justified by it's higher price. If Porsche really wanted to put out an incredible car, they'd stuff a 3.8 A96 DI motor and an LSD gearbox into a Cayman with big brakes, tires, and coilovers and sell it. They won't because it would highly cannibalize 997 sales.

An LSD is an advantage on most any car that is driven near its potential. Though, you must also differentiate between an LSD and a TBD (torque biasing diff, like a Quaife).

now can this be upgraded... or no

Yup. Can hypothetically be done with the gearbox in the car, but I wouldn't be comfortable doing it that way. So, figure gearbox out, great opportunity to do an IMS update and new clutch. A Guard TBD or Quaife are around $1800 I think, with a Guard LSD being about $2500.

This is all good information. Would anyone have more details pricing and specification as to what would be the right LSD to put into a pre 2009 boxster with Manual Tranny.

I've seen torque biasing or limited slip diffs available from:

Guard transmission
gbox transmission
quaife
Wavetrac

The 986S and 986 have different transmissions, so do the 987 and 987S, so they may not make a limited slip for all models. All range from $1700-2200

Thanks Blue2000. Do you have any experience with LSD? Is it worth the price of admission. Is it just good for track or will it help in street driving?

Since starting this thread I have been able to drive my car alot more and also get some experience with a friends car that has LSD. Necessary is a stretch but it does make the car more fun. Now, I would say that if your intent is improve upon the sports car that is the boxster then yes it is worth it. better launch, cornering and all that. (burnouts become more fun too but 2000 for better burnouts is well steap) Also if you do inclement weather driving then yes again. But if you rarely push your car and you just like to cruise moderately then LSD may not be the way to spend your 2 grand.


or think of it this way. you could spend 2 grand gaining a few HP or spend 2 grand making sure every pony you currently make is getting to the ground running. :cheers:

I had an open differential on my Rx-7 and then replaced it with a traditional clutch type limited slip. I noticed an increase in grip under acceleration, but also an increase in tendency from turn-in understeer to snap oversteer. The car's definitely more touchy in handling. It's very easy to break the tires loose on that car, so I could easily feel the differences with and without LSD.

A torque biasing differential will behave differently than a LSD and is probably better suited for the street. But in general, if you don't spend much time overpowering the traction of the tires, you probably won't see any difference in the way the car works.

practicallity
 

Before I had my Boxster, I had a Miata, and that had a limited slip. With all-season tires, it was actually good in the snow. That car never got stuck. Both wheels put the power down and and it could get out of just about anything. I've got a pickup truck with an open diff and it's been stuck in wet leaves.