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MG Midget and Sprite Technical - Limited Slip Debate: Quaife V Salisbury

We are lucky to have a choice of two different diffs.

My previous Grey car has a Quaife TorqueBias diff and EN40 halfshafts installed. We spun the end off one of the shafts and fitted a EN24 halfshaft which Peter May advised wouldn't work that well in the Quaife.... it didn't, so listen to Peter! :D We've got the EN40 halfshaft sorted so we could revert to that set up if we wanted to.

The new car came with a Salisbury diff fitted and one EN24 halfshaft on the nearside and a genuine works competition halfshaft made out of EN25 (and it looks like a standard halfshaft at the flange end!) on the offside.

I've heard conflicting advice as to which is the more violent and brutal on take up.

So the floor is open to debate.

Which diff and why?

Andrew
Andrew McGee

have you seen the diff on ebay?
N Sayle

can i have whichever is left?? lol
Mick - trying to sort the wiring

No N, haven't seen the one on ebay, is it worth looking at - although having two slippers already would be a bit greedy to have a third.

Sorry Mick, but we have a second "sensible" race car to start building as soon as this one is completed, so the less brutal one will end up being used on that one (if it ends up being the Junior car) or if we even have the opportunity to take on a fully modified car and bring that one back to life also so the brutal one would end up in that car.

A.
Andrew McGee

http://cgi.ebay.co.uk/MG-midget-LIMITED-SLIP-DIFF_W0QQitemZ290419382645QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item439e581975#ht_941wt_1165


This is only a few miles down the road from me. I'm semi interested
N Sayle

Tell Nev you want your book back!

The Quaife will always be easier on half shafts as you never put more than 50% (or thereabouts of the power through a shaft because any wheel spin locks the diff action, a bit like a welded diff.

A salisbury type plate diff will put more power through a single half shaft - up to approx 70% depending on how it is set up.

How does this stack up against your conflicting advice and where did the advice come from?

If it were my choice I'd run a Quaife in the dry and the Salisbury/plate diff in the wet.

I'm extremely interested in anyone else's opinions and from people wanting to buy orange silicone hose (crossflow or downflow.
Daniel Thirteen-Twelve

Oops sorry Daniel, completely forgot about the Orange hoses in the midst of "other stuff".

I'll search my email to find out how much!

Will PM you the learned opinions which are conflicting.

A.
Andrew McGee

IIRC the Quaife unit is torque biasing and requires the inner wheel doesn't lift off to maintain drive. It's in their documentation, if your set-up lifts a wheel then you lose the benefit of the LSD and drive. Food for thought.
David Billington

"a bit greedy to have a third"?
I think you need one for each ratio you are likely to use to avoid having to also swap the LSD unit across.
My car has a Quaife and apart from lighting up both rears off the line its presence hasn't made itself known anywhere else on the track. Perhaps when I change to another ratio running without LSD I'll notice its absence.
Lifting rear wheels only occurs if you are bouncing over the kerbs and that will certainly shorten the life of your half shafts.
Mike Allen

Mike,
Most folks with the wherewithal to think in terms of an LSD for each ratio are not running Spridgets are they? ;-)

Yes, you will find that the next time you notice your LSD will be when it is not there.

Perhaps you only lift a rear wheel when hopping kerbs, but my 72 Midget, with a PhantomGrip and a 3/4" front ARB, was very good at running on two wheels in fast skidpads whilst autocrossing on race rubber.
David "no photos, but lots of witnesses" Lieb
David Lieb

Yes David, I certainly can't afford even a 2nd one but I dream ...
Mike Allen

You could say the only reason we ended with two diffs was cos we (or Nev) destroyed the old car and the new one came with a diff of it's own.

However apart from the rolling shell and cage, we managed to salvage most of the important bits, so we're hoping to get a second car together using one of the other Midgets that I've got lurking here. :D

With the Quaife I could lay down the longest set of parallel stripes you could ever imagine, and I could behave like an absolute hooligan, hopping curbs. In fact the more like a hooligan you drove it the better it responded.

So either I'll have to lessen my aggression to get the best out of the Salisbury or it may prove even better for my bad behaviour.

Testing will tell I hope.

A.
Andrew McGee

affording a 2nd or 3rd one?!
i can't even afford the 1st

Onno Könemann

hi i run two lsd diffs a 4:1 and a 3:7( both plate ) depending on what circuit im on or what im doing with car ( touring etc ) as for plate v atb as been stated if a wheel is lifted on a quaiff it will spin up and the shock when the wheel returns to the ground is enough to shear the crown wheel on my mates RV8 and snap another mates escort half shaft ( with the escort we found on the tight turns of an auto solo circuit just the leaning of the car and weight transfer off the inside wheel was enough for the wheel to hop an spin , not good for half shafts ), also on a atb both wheels are only driven 50 50 under power when off throttle the diff is basically open where as a plate diff ( depending on its set up , ramp angles etc ) is a two way lsd so when off the power the load of decelleration will still mean the plates are locking , so in turn making the plate diff more progresive on and of power, me and my chums have been arsing about with lsd s for years and we always find the plate diff much more predictable in its delivery on and off power
Darren 2litre frogeye

It all depends on the preload on the Salisbury, they can be reet buggers if they're torqued up...

Quaife is the easier to drive and therefore better diff to run in most respects although I have read that they absorb more power. I like Salisbury's (but then I used to run a welded diff in FISC so I'm just odd...). I disagree with Daniel BTW - I'd run Quaife in the wet and Salisbury in the dry (if I had a team of mechanics to change it... :))

Put one into a 3.9 and the other into a 4.2 and swap around for circuits then you'll soon work out which you like best...

J
James Bilsland

We have a Tran-X plate LSD in the Minor with 45°/90° ramp angles and use the lighter of the 2 pre-load settings available. This means that on overrun there is no locking action from the 90° ramp angle, but some limited clamping from the pre-load.

Looking at the Tran-X website now, there are many more ramp angle options than when I bought ours, many of which are 2-way.

I chose the plate diff against the Quaife, as with anti-roll bars front and rear, and anti-tramp bars as well, the articulation is a bit less than than normal and it lifts the RH wheel very easily on tight RH bends, which could have limited the effectiveness of the Quaife, as it does not work very well (at all?) if one wheel has zero or virtually zero traction.

Most of the time you are not aware that it has an LSD, with two exceptions:

In the wet applying power coming out of a corner or roundabout can result in the LSD coming in and spinning both wheels, which does nothing for directional stability, so bit of care required!

In a RH corner under power, particularly on a circuit track day, there is a slight 'shimmying' at the rear, as the RH wheel becomes very lightly loaded and the power starts to overcome the pre-load and the 45° ramp angle. If I do need to take the diff apart in the future, I think I will fit a 35° ramp angle that is now available from Tran-X. What are the thoughts about that?

Otherwise an excellent diff, and unobtrusive, so long as you use an multigrade oil such as Castrol SAF-XJ 75W/140. Using an 'ordinary' 90 LSD oil, even the highest quality Catrol, causes all sorts of clonks and noises at low speed corners and manoeuvring - been there, done it!

Richard
Richard Wale

Will you lot please stop bidding on the one on ebay, it's starting to get expensive.
Brad (Sprite IV 1380)

There is one on ebay now?
Thanks for the warning Brad, your a real gent! :)





Just kidding!

I already have a quaife LSD in my midget and like it for the use i have for it: unlease the Kpower on both shafts and some playing with fast road use.
I will check what oil ive been using, thanks for the warning Richard.
Arie de Best

Arie,
thats good to know, what ratio are you using & where do you park your car?
Brad (Sprite IV 1380)

£361.99 for the one on ebay, someone wanted it!
Brad (Sprite IV 1380)

Brad, 3.9 but it only fits fine-spline 1/2 shafts but lucky for you: they are in the same axle as the LSD is! LOL
Arie de Best

Well i can see an LSD on my shopping list when the Eaton is in, but for now i have a collection of halfshafts to get through first.
Brad (Sprite IV 1380)

salisbury is better IMHO. I agree with James also, Quaife more forgiving in the wet, Salisbury better in the dry.

I have run both in multivenue rallies and auto tests in ireland and the plated type is far superior for my use. It is a lot more aggressive which is good as we tend to need to use the diff to keep the car turning on a vast array of surfaces. Teh quaife was not up for the job at all.

If you have the luxury keep both and use plate for dry, Quaife for wet, or pony up and drive plate entire time!!

good luck on your decision.


WDT Corry

This thread was discussed between 29/03/2010 and 08/04/2010

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