Best LSD for 915 ?

[stv951]

I am considering to install an LSD to a 915 Gbox. What are the options available apart from quaife ?

I searched at Pelican, but it doesn't sell an LSD for a 915 box. Any directions and opinions please ?

[ttweed]

I think Paul Guard at Guard Transmissions makes the best units. That's what I have in mine. He posts here as "Geary", so do a search on that username or just go to his site and give him a call. The type of LSD you want will depend on your usage of the car.

TT

[Cory M]

Originally Posted by ttweed

I think Paul Guard at Guard Tansmissions makes the best units....

+1

[Mitch Leland]

Howdy,

I'm thinking of replacing the missing LSD rear end that was optioned on my car. Someone for some reason took it out. If you're doing 1 or 2 DE track events a month is it worth it?

I have my engine and tranny out now so it would be easy to make the change, less the $2,000 for the Guard LSD unit. I've talked to Paul Guard and he's a good guy with good follow up. And from what I can tell he has the best LSD on the market. If you contact him he'll send out a complete information package to ya.

[Tom Oxner]

I bought a used Guard Transmissions Torque Biasing limited slip for my 72 911 with the 915 transmission. I had previously installed a ZF clutch type limited slip. I use the car primarily for street and autocrossing. The TB diff is GREAT! The car leaves really hard and the turn in slower corners is much improved. If you intend to use the car for track use, the clutch type is much better.

Tom Oxner

[KTL]

Originally Posted by Mitch Leland

If you're doing 1 or 2 DE track events a month is it worth it?

Without a doubt in my opinion. I do maybe one a month when I have the time. I always come away from the track saying to myself I have to get the LSD for my car. I see people do things I just can't do with my car- trailbrake/brake later and power out of the corners with MUCH less wheelspin. If I could limit the amount of wheelspin my car suffers from, i'd be shaving a second or two off my times with ease. Not to mention the tire wear!

[Bill Verburg]

For De's, From best to worst(but they are all good)
Guard asymmetric 40/60 or 50/80, guard symmetric 40, ZF symmetric 40(early mit 4 plates)

some will argue for a symmetric 80 but IMO that's a race only option

[Mitch Leland]

Bill and Kevin,

Sounds like it's something I should do. Particularly since the engine and tranny are out of the car and I'm having the tranny gone through. So it would be cheaper now (if cheap is the right word) to have it installed now.

Thanks,

[juanbenae]

i just did my 1st DE with my new guard set up and it was unbelievable the difference. i knocked a second and a half off my best time at sears point after one event. i had been stuck at a lap time for the past three or four events there and just like that i was quicker. still i dont feel like ive relearned the car complete like and still i was faster.

will be doing sears again later this month and feel there is another second to shave as i become more accustomed. biggest feel of the difference at sears? from 9 decel into 10, stable like mable...

T$

[rpiper]

I had the ZF in a G class PCA car (with 4 clutches) and it was amazing. Then I had the Guard symettric 40 in a street car; also fantastic. I drove a hotrod RS clone with a quaiffe and didn't like the way it was locked on accell but not on decel, so you'd get uneven engine braking. It really unsettled the car.

[euro911sc]

If you want to run in PCA Stock class do you have to have a ZF?

-Michael

[rpiper]

technically,yes, but the ZFs are REALLY hard to find and the Guard unit is functionally identical (clutch type). It is no advantage compared to the ZF, and they'd have to tear open the diff to see that you had a chromalloy Guard unit rather than the ZF.

[dd74]

Guards are what? $2K? I've seen the price somewhere, but can't remember.

[Bill Verburg]

Originally Posted by Mitch Leland

Bill and Kevin,

Sounds like it's something I should do. Particularly since the engine and tranny are out of the car and I'm having the tranny gone through. So it would be cheaper now (if cheap is the right word) to have it installed now.

Thanks,

The lsd can be replaced now or later after the trans is installed.

Remove the axle and sidecover for access.

[Bill Verburg]

Originally Posted by euro911sc

If you want to run in PCA Stock class do you have to have a ZF?

-Michael

That or an open diff.

[Britain Smith]

Does anyone have some details how a LSD is installed.

-Britain

[Mitch Leland]

Britain,

My mech said that there was some set up to it, and I think unless you really know your way around transmissions and rear ends I wouldn't attempt it. The risk/reward is too high...

[ipapilot]

For those concerned with the legality of different diffs in PCA club racing, you may want to weigh in on the proposed rule change that may allow a Guard or similar unit due to the scarcity of the factory units...

[euro911sc]

Bob,

Yeah, I know its unlikely they would look there... but I'm one of those guys that will follow the rules even if it makes me last place... I just want my skills to win... not my car... which means I will most likely never win anything but have fun trying I'm ok with that for the moment

Brian,

Where do I send my letter/e-mail? would love to have some options in the future as ZF units are very hard to find...

-Michael

[KTL]

Originally Posted by Britain Smith

Does anyone have some details how a LSD is installed.

-Britain

There's a thread on here called "Need Bearing PreLoad Specs" by Dentist90.

Need Bearing PreLoad Specs