Iridium

I've been searching through threads to investigate the various options for moving to either an LSD or torque biasing unit rather than the open diff on my 996 turbo (in the rear), and most of the posts are debating the theory of if it's valuable or compatible with the PSM (car is 2001). Didn't really see any "I have done it and it was great/totally sucked."

The open diff and PSM wind me up, in that I'll expect the car to do one thing and rather than that I get a one-tire-fire for a moment and then the extreme PSM clamp down ;-). Would much prefer to lessen that interaction and have a proper diff in the rear, and have the rear step out a bit but put power down. I know Porsche offered one late in the run in the turbo S, but couldn't see anything discussing if the PSM was different or not.

I have the trans out at the moment, so doing it is easier than not. This is for street/autocross use rather than a track rat. Who has done this and what was the experience, especially between the torque-biasing units and a plate style LSD?

k9turbo

i've never had a plate type lsd - and never felt i needed one. opted for the wavetrac years ago after deciding to remedy MY "open diff" after removing the cardan.. car was rwd for many years and now reverted back to awd still ( obviously ) with the w'trac installed.

it does everything i ever wanted in terms of rwd power to the wheel(S) ( as opposed to one wheel lol ) and never needs maintainence or rebuilding - that plate type lsd's will depending upon length of time in service and or/track abuse.

its 1300 bucks. lifetime guaranteed, gear driven ( nothing to "break" ) and contrary to popular belief - presumably by those that have never used it in extreme downhill braking, as i have..

will not allow "tail wag" under hard braking. or spend a few grand on a plate type. street car? no "need". believe that.

k9turbo

easier to stick a fork into a thread - than it is to re-insert the clutch fork lol

Capt. Obvious

General consensus seems to be that if you track the car a lot and/or want maximum performance, go with a clutch-type differential (Guard, OEM). They require periodic rebuilds and are more expensive. For a street car that might see an occasional track day, the Wavetrac is popular because as K9 mentioned it needs no maintenance and cost of entry is lower.

993GT

what the market really needs is a LSD for Tiptronic cars...

k9turbo

exactly. tracking? = plate type. street? = w'trac is perfect

theprf

I'd buy one...

69911

.
For AutoX, the consensus among serious driver's seems to be the Plate type is needed to gain full chassis dynamics. Read the threads on the highly prepared cars.
My use is street/AutoX also. I weighted Wavetrac vs plate for a while and eventually chose the GT plate type when I had trans out for a clutch. The back of the car is certainly more "lively" under modest power; exactly what I was looking for.

THP23

Another vote here for Wavetrac. My car is 80% street and it's been wonderful.

Outlaw 06

Here’s my ongoing experience with helical vs. clutch-type LSDs.

I haven’t really driven my 718 Spyder yet, so I can’t comment on the LSD in that car. I recently installed an M Performance (clutch-type) LSD in my F22 M240i to replace BMW’s abysmal stock open diff in that car. The M Performance LSD greatly improved the power delivery to the rear wheels in that car. It’s literally a night and day difference. I also have a stock, clutch-type LSD in my E46 M3. I have helical LSDs in my Honda Civic SI and my NB Spec Miata race car.

When both drive wheels are on the ground, I can’t tell any difference between helical and clutch-type LSDs. However, whenever I find myself in a situation where one of the drive wheels momentarily lifts off the ground (perhaps when taking too much curbing on a track), the helical LSD’s power delivery/traction is less predictable and inferior to a clutch-type LSD. That’s the only “con” of helical LSDs in my experience. For a street car that may or may not occasionally be tracked, a helical LSD is probably the way to go.

Iridium

I went with the Guard, and it's going in the car now, will report back once that's done! Think I should have the car back this week...

blockhed

I have a brand new guard gt2 lsd laying on my shelf collecting dust if you're looking to go that way.

larry.beck

I had a Guard diff installed this summer. Love it, but it’s a “drive-to-track” car for me.