LSD choice for street use 3.2 Carrera ?

PorscheRally · PorscheRally's Garage

Dear Friends,
I am planning to fit a LSD to my street only use Carrera 3.2. The car does not have any suspension upgrades other than brand new everything and the Sport Blisteins all around. No stiffer bushing, no stiffer torsion bars. However, I may try a very mild upgrade on the bushing side in the future.
Apparently, there are 2 types of LSDs for the 915 box. 1- plated lsd 2- torque biasing type ( Wavetrack, Quaife etc )
As a non Porsche rally car builder, I am very much familiar with the plated type of LSDs and how to set them up etc for different conditions but due to the nature of rallying, we are not very much involved with the ATB type Lsds.
And I thought, I would certainly have to hear actual driver's experience and advice for the correct decision before such an investment.
Therefore, I would very much appreciate if you could share your experience with your lsd fitted street cars.
Regards,
Kerem

Driven97 · 01-04-2016, 04:15 PM

I'm a huge torque biasing fan - they're quiet, operate almost invisibly, and just plain work under most street conditions. Never driven a 911 with one, but have owned and driven several fwd and rwd cars with them, and have not been unhappy with any of them save for one fwd car with electric steering - had some gnarly kickback.

That said, I went with a clutch type for my AX/street car because I wanted the locking on decel for my 911.

impactbumper · 01-04-2016, 04:48 PM

Has anyone used Wavetrac lsd? I installed tons of them on BMW/VW/Audi crowds and had nothing but great experiences.

Duc Hunter · Duc Hunter's Garage

I have heard Wavetrac are great. I was a Quaffe guy myself for years. I have heard Wavetracs are even better..for street or track.

impactbumper · 01-04-2016, 05:07 PM

Quote:

Originally Posted by Duc Hunter

I have heard Wavetrac are great. I was a Quaffe guy myself for years. I have heard Wavetracs are even better..for street or track.

I was a Quaife guy myself till I discovered Wavetrack a while back. Never turned back. I might take the plunge on this mid summer.

impactbumper · 01-04-2016, 05:08 PM

Kerem bu arada ben de Istanbul dogumluyum, sevgiler!!!

gliding_serpent · gliding_serpent's Garage

I got a Guard clutch type LSD. I had Matt set it for the more moderate and street friendly 40/60 (at his advice). Benefits on acceleration, and braking. Torque biasing only help on acceleration. The less aggressive ramp settings make it easier to turn also. Never noticed it on the street. Not invasive.

On the track I do not notice it either, except that my wheels don't spin, and I had about three people remark about how I left them in my dust on corner exit on the track (HPDE). I remember catching a 944 turbo race car out of our hairpin... his inside rear wheel was lighting up with smoke, and I just reeled him in. A faster car could just not catch me because I punched out of the corners so much harder than he did. He caught me in the high speed turns... and then bam, I was gone after the next corner. We were like a yo-yo.

But, if it were me, I think you have more gains in other areas of your car (and the driver, by default, we all need more work) to address first. Not sure the expense is worth it on a street car. If you are pushing that hard to really need it on acceleration or braking, you are asking for it.

Still, if you were redoing your gearbox like I was... short gears and a LSD is VERY tempting... they made me a very happy man.

impactbumper · 01-04-2016, 05:56 PM

Gliding how much was the dif itself?

gliding_serpent · gliding_serpent's Garage

Matt is on the boards and will give a pretty heads up answer on pricing.

Driven97 · 01-04-2016, 07:10 PM

The Guard stuff isn't the cheapest, but by far has the best reputation around these parts.

Steve@Rennsport · 01-04-2016, 10:01 PM

Another opinion based on some experience:

1) Torque-biasing diffs are best for FWD cars since they minimize torque steer while allowing the application of more power on corner exits. These really stabilize FWD cars in many ways and reduce that inherent understeer.

2) 911's really benefit from clutch-pack diffs due to major improvements in stability under trailing throttle & braking as well as better application of power on corner exit. I'm a big fan of the Guard units over the others so thats all we will install & use.

RL technical · RL technical's Garage

I have several guard transmissions lsds in my cars. They are fantastic, I also have a spare one for sale at 60/40 lock rate, pm for more details.
Just to let all you guys know these diffs are manufactured locally here in Melbourne Australia.

Driven97 · 01-05-2016, 06:03 AM

Compare the photo of that beautiful Guard above to my 915 KAAZ and the difference (pun!) is pretty (pun again!) apparent.

Geary · 01-05-2016, 09:22 AM

Thanks, Steve .. Attention to machining detail is only part of what lifts GT diffs above the rest. Another part of it is material selection.

We once had an unfortunate incident where a jealous competitor tried to rig a GT LSD to fail. The LSD was disassembled and a small chisel was used to weaken the cover plate all the way around, so that it would be sure to crack like the early factory Cup LSDs. Only it didn't. Those 9310 cover plates are virtually unbreakable.

Porsche 2 · 01-05-2016, 11:15 AM

To be controversial, for street only, unless you expect to be subject to driving in slippery conditions (freezing or mud) why spend the money?

Bill Verburg · Bill Verburg's Garage

Quote:

Originally Posted by Porsche 2

To be controversial, for street only, unless you expect to be subject to driving in slippery conditions (freezing or mud) why spend the money?

Actually that's one reason factories are loathe to install lsd oe. and when they do install one it's usually pretty wimpy or a gear type or an electronic type. W/ a functional plate type when both wheels have little traction this will tend to induce a spin. One example cruising along when you hit a fully ice slicked road. Both drive wheels will spin rather than the 1 in an open diff. This doubles the tendency to spin.

plate type lsd, and even more so asymmetric plate type lsd are great for all the reasons Steve Weiner already mentioned. But this is mostly seen in track type use.

gear type is more favored by a/x types as it does't induce understeer like the plate types but does apply power to the wheel w/ traction w/ power on.

PorscheRally · PorscheRally's Garage

Dear Friends,

Sorry for the late response, it is due to big time difference and a hectic day in the office and in the workshop.

Many thanks for all the replies and vast amount of information.

I am trying to digest all the posted information in this thread. Clearly, there are pros and cons of the both units. Due to its nature, clutch type of lsd needs certain amount of driver alertness under demanding conditions but offers a better response ( both ways ) and it is probably much more responsive when it comes to agile driving where as gear type lsd works in a leisurely style.
I have also heard that gear type lsd becoming more and more popular among the BMW and MERC drivers but I have a feeling that the experience in a 911 could be somehow different than the other mentioned rwd cars.
For me, it is hard to judge and that is why I am very much depending on your personal experiences in road going ( or fast road ) 911s.
To be honest, since I am well familiar with the plated lsds on rally cars ( both tarmac and forest driving ) and this familiarity is kind of pushing me towards the plated type but then having no experience with 911s with lsds is making me think twice

I guess this is why I should continue to digest and judge pros and cons of both systems.

Dear Berk / Sevgili Berk,
I am very happy to run into a Turkish friend in this forum. What a small world !!
I understand that you are very much involved in the cars. Are you involved professionally or as a hobby ? I have a workshop in Istanbul and we are mainly preparing Historic rally cars, restoring sports classics etc. ( not my full time but I am very much involved- I build our engines, run the rally team and also drive time to time ) and the lsd question is for my own 3.2 Carrera.

Burada tanistigimiza cok memnun oldum, umarim temasta kaliriz. Cok sevgiler.

Regards to everyone,
Kerem

G450X · G450X's Garage

Quote:

Originally Posted by Bill Verburg

Actually that's one reason factories are loathe to install lsd oe. and when they do install one it's usually pretty wimpy or a gear type or an electronic type. W/ a functional plate type when both wheels have little traction this will tend to induce a spin. One example cruising along when you hit a fully ice slicked road. Both drive wheels will spin rather than the 1 in an open diff. This doubles the tendency to spin.

plate type lsd, and even more so asymmetric plate type lsd are great for all the reasons Steve Weiner already mentioned. But this is mostly seen in track type use.

gear type is more favored by a/x types as it does't induce understeer like the plate types but does apply power to the wheel w/ traction w/ power on.

I experienced the "spin out" pull from the LSD in my '05 M3 while creeping (maybe 15 mph) on a mountain pass when bad weather (snow and freezing rain) came out of nowhere (it was 55 degrees and sunny at the base).

It was a shock to have the rear spin slowly out of control and the normal corrective turn into the spin at very low speed had no effect. I managed to get it stopped without hitting anything and a mile later I was out of the bad weather. I guess I should have put the transmission in neutral to remove the pulling action of the LSD and trusted the ABS and DSC...

I have a Wavetrac for my 915 that I hope to have JW in Seattle install soon. I heard positive comments about the Wavetrac in a 915, and it was reasonably priced. I wanted a Guard, but could not come up with the funds. I did luck into some decent prices on close ratio Guard gears though. For some reason I seem to be able to save up around the $1k mark, but beyond that (especially near $3k) I start to have trouble!

gliding_serpent · gliding_serpent's Garage

Yeah, me too... Once i save up i find more parts to buy...

Matt Monson · 01-06-2016, 09:19 AM

Hi guys...

Been a busy start to the new year, so not on the board much the last few days. Our LSD for 915 runs $2500. They are in stock.

That said, I don't know that it's worth the extra $1000 over a TBD for a street car. I run a TBD on my 914. They are great on country roads. You just need see the speed or threshold braking on the street that warrants the lock up under braking that the LSD provides. TBD should be fine. I'd pick a Quiaffe over a Wave-Trac. Though we also make TBDs. People just don't often realize that because the LSD is our claim to fame.

Regards,

Matt