[Fot] LSD diffs, what specs to choose?

[Keith Files]

Here is my view.

I run Salisbury LSDs in both my TR4 and my TR6, both cars have 3.9:1 and
4.1:1 ratio CWPs.

In the TR4 the LSDs are virtually maintenance free and do exactly what they
need to do on the track. TR4 has 147 bhp at the rear wheels.

In the TR6 the LSDs need to be rebuilt after every 5 hours of track time and
it is always the clutches that need replacing; rebuild kits are around #100
GBP and it takes 3-4 hours labour. The TR6 puts out 207 bhp at the wheels.

I have recently installed a Gripper LSD in one of the diffs for the TR6;
these are manufactured by Gripper in the UK and are designed by the guy who
originally designed the Salisbury that is manufactured by Tran X but has
taken them further by making them stronger in a number of areas which,
according to them, will result in low levels of maintenance at a lower cost
as well. I am running this LSD at the Nurburgring Nordschleife 3 hour race
in early September to prove it fully; it has already run faultlessly at
Silverstone.

The Gripper costs c #700 GBP + VAT (tax) making it #840 GBP in total.

I will provide a write up and further details on the unit itself after the
event if there is any interest.

Cheers,

Keith.









-----Original Message-----
From: fot-bounces at autox.team.net [mailto:fot-bounces at autox.team.net] On
Behalf Of Alexandre Camoletti
Sent: 25 August 2011 00:15
To: fot at autox.team.net
Subject: [Fot] LSD diffs, what specs to choose?

Dear FOTers,

Have to install a LSD in my TR3. As the diff needs to be rebuilt, I take the
opportunity to install a LSD.

It will be a (very) fast road car, fully prepped for long distance road
rallies in various conditions  (Winter, Summer, dry, wet, snow).

I would like the car to remain predictable and driveable in all sorts of
real road situations, so it has to be some compromise I suppose, but I do
not know the influence of the set up parameters.

I know little about LSDs, hence a couple of questions:

1)      Quaife (gear driven) or Salisbury (disc type)? I know the Quaife
does not work with one wheel lifted, but has not the problems associated
with disc type (oil quantity and heat)

2)      If Salisbury type: what ramp angles? I heard of 45/45, 45/60, 30/60

3)      Re Salisbury again: the locking should be lightweight or fully
interlocking?

4)      Salisbury still: looks like TRAN-X in the UK is the one
manufacturing them or did any one of you have good experience with another
Salisbury type LSD manufacturer?

5)      Still Salisbury; should the RACETORATIONS finned cover be fitted to
increase cooling and oil capacity, or is not critical in a fast road
application?

6)      There is also the PHANTOM GRIP possibility , what is it and is it
worthwhile?

Thank you in advance for your feedback!

With kind regards

Alex Camoletti
_______________________________________________
fot at autox.team.net

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