LSD - best types and sources ?

[skydragon]

I've recently aquired an ex-SuperGrad car (2003, 1.6 K-series, De Dion, 5 speed) and would like to fit a LSD over the winter.

 

- what are the best LSD types to fit ( FWIW I hope to get the engine tuned to approx 150bhp at some point in future)?

 

- best places/ways to buy ?

 

Thanks.

[Willie.]

Plate type LSDs are the best.

 

Stay away from Quaife ATB as they're not really LSDs and aren't the best job.

 

Go for a TranX or ZF. Both are plate type, TranX has metal plates, ZF has a friction surface type as far as I know.

 

ZFs tend to be viewed as the better of the two, possibly because they are what Caterham fit. I've never had a ZF so don't know. They can be hard to find. I've a TranX, good thing about it is you can reverse the plates so you change the bite of the diff.

 

Try Road & Race Transmissions for a ZF, but be warned, he'll try to get you to wait for a new LSD that is coming out (That was coming out 2years ago when I was after an LSD). I rang TranX direct, got a really dead on bloke (Dan I think he's called) who understood Caterhams and sorted me with the right preload/ramp angles etc.

 

LSD is the single best upgrade I've ever done to the car. Fantastic fun in every regard.

 

Willie

[skydragon]

Thanks for the info, much appreciated.

 

Looking at Caterham's online store, they appear to only supply the Quafe ATB LSD and there is no mention of the ZF LSD unit (perhaps they don't sell it via the online store?).

 

How much did you pay for the TransX unit?

 

I'll make a few phone calls and see what more I can find out.

[rj]

The ZF unit is not available new. You'll have to find a second hand unit.

 

I don't think CC have ever supplied the ZF LSD but could be mistaken.

[I.Mupferit]

My CC supplied diff is a ZF unit. Supplied with the kit in November 2004.

 

The only reason I know it is ZF is because Phil Stewart at Road & Race has just rebuilt it for me and told me what type it is. It was very noisy from new due to wrong setting of the bearing preload (by CC) apparently.

[Willie.]

My TranX was about £700 if I remember correctly.

 

Willie

[neil.cavanagh]

quafie ATB is perfectly good for the job. Opposite lock is giving a rather one sided version of the story.

 

I've been running a quiafe for 2 years now. It is not quite as aggresive as the 'plate' type ones in locking up, and might not lock up 100%. But then it was good enough for me to win class 4 in the club speed championship last year so can't be that bad?

 

I can still do donuts and spin turns with it, which frankly is the main reason most 7 drivers if they admit it want a LSD.

 

PLus points of quaife are:

1) it is available... ZF are rare as hens teeth now as out of produciton I belive

2) Cost... even when ZF were readily available quaife were cheaper.

3) noise/drive shunt. Quaife GENERALLY are better for this. You can get a good ZF, but seems more common for a ZF to be noisey and/or have noticable shunt.

4) Less aggresive lock up behaviour... better for the road.

 

Negatives are:

1) armchair racers will tell you you don't have a 'proper' lsd.

2) in-extremius they do not lock up 100% like a plate type can.

3) umm.. thats it.

 

So decide how you want to use the car, and look at what you can get a make a decision.

[ECR]

And they don't wear and need re setting like plate diffs ...

I've had one for 15 years and am quite satisfied with it (I've been known to lift a few trophies as well 😬).

 

Ex Chairman Roger

[Jason Plato]

Ohhh - your on Quaife atb are you Roger ?

 

could you describe how it feels vs a plate diff in real terms ( in your driving on the limit of adhesion mode

 

do you ever find it feels like it goes "open" and spins up an inside wheel and does it push on into corners ?

 

Dave

 

here is C7 TOP

Taffia rear gunner

 

[rj]

 

At 193BHP my car alway spun a wheel when I had an open diff. On aggressive acceleration that is. This was cured once the LSD was fitted. My LSD is "proper" meaning it a ZF - and it's NOISY. Not just noisy but NOISY!

 

I mainly use the car on track, so it's not really an issue to me, but don't expect a ZF to be quiet. My diff was set up by R&R, so I would guess it's done properly.

 

 

/regin

 

Edited by - RJ on 27 Aug 2008 16:06:22

 

Edited by - RJ on 27 Aug 2008 18:55:59

[Jason Plato]

I'm currently on a ZF, new and installed by phil at road and race 5Kmiles ago. But now I'm considering a diff ratio change and I might simply use my spare casing in the garage and insert a new lsd and kep the other ZF plate one for spare and such like.

 

 

 

here is C7 TOP

Taffia rear gunner

 

[Willie.]

Neil & All,

 

Apologies for apparantly slagging ATBs, I sent my email late last night so wrote it quickly before hitting the hay.

 

To explain what I mean; plenty of people have Quaife ATBs and have no problems with them, but an ATB is not an LSD. Its a torque biasing diff. I understand that it works by transferring torque (Drive) to the wheel with the most grip. However, because of the "bias" bit, they rely on a bit of grip on the other wheel. So if its in the air, the wheel can spin. This can give all sorts of shocks up the transmission when it comes back to earth. There have been all sorts of rumors of gearboxes getting wrecked because of this...but I've never met anyone who suffered this.

 

I'm no genius on ATBs, my "knowledge" is just what I've read and I've never bothered to study exactly how they work. Apparantly they never truly lock up 100% and can feel unsure while cornering (A plate type locks and that's it, whereas an ATB will be biasing about as you corner).

 

I can't remember exactly how much my TranX was, it may have been only £500, but at the time I looked into it and decided that it was worth spending the extra money to buy a LSD that I knew would behave exactly as an LSD should.

 

The ATB is not and LSD. One moves drive/biases torque...one locks and allows slip.

 

Buy what you like, it won't affect me.

 

Willie

p.s. I bought mine mostly for doing donuts and fast U-turns. Its also fantastic on track, 4/5th gear and you can have a lovely predicable slide. Its also as quiet as an open diff.

[S47zz]

IMO - An ATB is a soft LSD, and is well suited to a 7, power usually gets transfered to outside wheel when cornering, unlike an open diff which transfers power to the inside wheel which then spins 😳

Driving on wet grass it feels weird with ATB coz the wheel with the most grip varies constantly and you can feel this when driving a 7, nevertheless the drive is maintained, no lockups like an LSD would do in similar situation.

I like my ATB and wouldn't swop it for an LSD.

 

[Mavic82]

I too have an ATB and feel that unless you are an out and out track racer that this is the better option particularly in a 7.

 

As mentioned already you are very easily able to donuts (as I inadvertently demonstrated on the fish and chip run 😬) and although many would say it is not possible they are also excellent for drifting!

 

However another LSD to consider which I quite like in a 7 is the AP surtrack.

 

Cheers

 

Guy

[7 wonders of the world]

*thumbup*for Dan at Tran X very helpful when I got mine from him along with a gear kit

 

Too young to be old !

[7Nut]

Very pleased with my ATB, no increase in noise factor over the original diff either

 

Stew

[The Laddie]

Is the Tran-X LSD for an '06 1.6K 5 speed, the 7 inch Sierra version?

 

Enjoy,

 

Mike

[Jason Plato]

yes

 

here is C7 TOP

Taffia rear gunner

 

[Englishmaninwales]

A Quaife ATB transformed my car (compared to an open diff) on track, but I've not had a plate type for comparison.