LSD for 915 transmission?

[hightuned]

Just got the new bearings for my 915, i sourced top quality SKF(what else would a Swede buy) bearings from a company supplier to get a good deal and still hade to pay about $2400 ouch! Well enough complaining, now i need a LSD and am looking towards a Quaife QDF5Q and am wondering if anyone has tried it, or would recomend another LSD?

[Canada Kev]

I'm sure those that know better than I will give their two cents, but if I was in that situation, I think I'd not use the Quaife. As I understand, it doesn't give the same benefit on deceleration that it does accelerating. But I would also talk to a bunch of people that know what they're talking about before I made up my mind.

Perhaps give Matt Monson from Guard Transmission a shout. He's also floating about here, and might give his opinion.

[Matt Monson]

Originally Posted by Canada Kev

I'm sure those that know better than I will give their two cents, but if I was in that situation, I think I'd not use the Quaife. As I understand, it doesn't give the same benefit on deceleration that it does accelerating.

Perhaps give Matt Monson from Guard Transmission a shout. He's also floating about here, and might give his opinion.

Thanks for thinking of me. That part about not giving any lock up on braking is a characteristic of a TBD (torque biasing differential). A Quiafe is not a true LSD, regardless of what their marketing tells you. An LSD has a limit to the amount of slip it allows. A TBD, like a Quiafe, goes open at the limit (like on ice or when you lift a wheel).

Knowing a bit more about the OP's intended usage would best help us to provide guidance. Guard Transmission manufacturers TBDs in addition to LSDs. We don't have an actual bias one way or another. It all depends on what kind of build the owner is doing and how they intend to use the car.

[hightuned]

Thx, i should ofc have provided more facts about the intended use. I know its not a true LSD but as turning 40 is closing in on me the car will only be used to impress young women with peel outs at the crosswalks of the local collage!
All kidding aside ofc i would perfer a true LSD as the car will be used on trackdays aswell as country roads. I does not have to be adjustable and can be on the soft sida as the car will se more street then track. The quaife caught my eye as the price tag is only $1270.

Fredrik

[Tom Sch]

hello,

i use quaife TBDs since some time with great success - most time on the track, some times on the street/mountains.
the big advantage is the ability to allocate torque in a soft way to the wheel with the most grip. no surprises with abruptly opened friction...
if you brake it will do nothing other as a normal open differential will do.

thanks

[hightuned]

Thx Tom, if you dont have any problems at all using if on the track it will work just fine form me. I doubt there is a cheaper diff then the quaife to be found out there?

[hightuned]

Looking into this some more and found the Kaaz LSD - $1700
Wavetrack TBD that works even if there is not traction on the other wheel -$1400
Cant realy make up my mind, anyone got some more input for me?

[0396]

If it were me, I would look for which ever comes up first. ZF and have it rebuilt using Guard replacements and or a new / slightly used Guard.
No TBD for me.....60-80% locking when you come out of a turn, where ever your cars pointed is where she's going, unless your totally out of control -

[Mothy]

I'm not sure who sells them worldwide, but I have a Modena LSD in my 915 and am very happy with it for track days and street use. Modena Engineering is based in Victoria, Australia but ship nearly their entire manufacturing output overseas.

Learning to drive it on the limit with an LSD is a whole different story.......

Tim

[3literpwr]

I have run KAAZ on my previous rally car and ZF in my 944 S2 with good results... For me, a plate type diff is the only answer.

[Danish Dynamite]

I run a Quaife TBD in my 915 7:31 box with a 3.0 Liter 260 hp engine.

It made a HUGE difference from running a regular differential.

It gives a lot of confidence in the turns, and I could go alot faster on known parts of tracks. I am not saying a true LSD wouldn't be better, but the Quaife suits my driving style. I can really feel how it keeps locking going into a 3rd gear turn uphill which gives me the pleasure of just giving more throttle.

/Christian

[sig_a]

Originally Posted by hightuned

Looking into this some more and found the Kaaz LSD - $1700
Wavetrack TBD that works even if there is not traction on the other wheel -$1400
Cant realy make up my mind, anyone got some more input for me?

Save some $$$$$.......

KAAZ online store sells all Porsche clutch plate style LSD models for $1525.

[Turbo Den]

what LSD is preferable for ice-racing / rally on snow paved back roads?
thanks.

[Driven97]

No expert but on ice / snow I'd go with a clutch type. A biasing diff needs some resistance from the opposite wheel. A clutch type does not.

I chose a KAAZ for budget reasons, but if you search the forums you will not find a single person unhappy with a Guard.

[Matt Monson]

I'm not sure who sells them worldwide, but I have a Modena LSD in my 915 and am very happy with it for track days and street use. Modena Engineering is based in Victoria, Australia but ship nearly their entire manufacturing output overseas
Learning to drive it on the limit with an LSD is a whole different story.......

Tim

That's because the whole Porsche product line is my intellectual property. We make no secret of the relationship. They come over to the States and we share a booth at the PRI trade show.
We have a gentleman's agreement where Frank can sell the locals the overruns of lsds, usually 915 and G50 models as those are our big movers. You could say it is kind of a Honda and Acura relationship.
Turbo Den, got your email just before I shut down my computer for the night. Pelican is fun time on my phone and not work. I will email you tomorrow. Even this post is more typing on the phone than I like to do.

[Mothy]

Well I'm glad your gentleman's agreement works - us 'locals' benefit from it.

Happy camper here.

[TechnoViking]

I have a Quaife LSD for sale. $900.

I ran the Quaife for years and switched to the clutch type as someone mentioned it might help my trail braking.

Unless you consider yourself to be quite advanced on the racetrack the Quaife will do fine. Until you are pitching the car in pretty hard and braking in places your DE instructor tells you not to, you probably wont notice the difference.


PM me if anyone wants the Quaife.

[targa44]

I had a Boxster S several years ago and went with a Guard TBD that they had just introduced for that model.... It took some time to adjust, but as an autocrosser, it helped rotate the car coming out of a turn.

Is the general consensus still AX with a TBD and track with LSD?

thanks,

[Driven97]

I think the answer is, "it depends."

For my car, I wanted the added stability off throttle, so went with a clutch type for AX. Thing really works, but I'm going to need to make some setup changes, and relearn some driving technique to take full advantage.

For a more conventional car, I prefer the seamless nature of a TBD. I think it's much smoother and more predictable. You don't really notice it doing it's thing, even though it is. Other people prefer driving on a clutch type.

If you can find cars with both types, it's a great way to see how the different types work. I drove both types in STX RX-8s, you can sometimes find STR Miatas with different types at the same event as well.

[Patrick3000]

This is an interesting question, I have a 77 Targa with an 82 Euro 3.0 about 204hp, and a 82 915, 15x6 Fuchs square with 195-65 tires. No aero, mostly street and set up fairly soft but may see the occasional track day.

What's the recommended LSD?