gml7
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| posted on 19/10/10 at 07:25 AM |
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Limited Slip Diff for a Striker
Hi guys,
I'm looking at putting a limited slip diff in my striker, it currently has a standard 7" sierra in it. There seem to be several units out
there but i'm not sure which will be most suitable for a striker. Does anyone have any experience as to which would be the best?
I would like to start hill climbing and sprinting and I'm still trying to get to grip with the regulations. Would an LSD exclude me from any
classes? I know its circuit racing, but i saw in the 750mc rules for the kit car championship that lsd's were not allowed. Is that correct?!
Thanks for any help!
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mookaloid
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| posted on 19/10/10 at 08:12 AM |
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I don't believe that LSD's are illegal for hill climbing and sprinting.
The most popular one seems to be the Quaife ATB for the sierra diff. I'm not sure that there is a plated one even available for the sierra
application.
Cheers
Mooky
"That thing you're thinking - it wont be that."
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CNHSS1
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| posted on 19/10/10 at 08:40 AM |
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Ford fitted viscous 7" LSDs to 4wd sierra and escort cosworth rear, Xr4x4 rear (3.9:1 for 2.0L, 3.62:1 for V6 models).
aftermarket wise, Quaife sell the ATB 'torsen' style diff, Tran-X, Gripper and ZF all do plated versions for the 7".
ford viscous are generally £100-£200 s/hand, quaife diff only (not fitted into your case using your CWP) approx £500, plated about £550
for sprints/hills, lsds are certainly legal for MSA Mod Prod and Mod Specialist production, but you would need to check basic Roadgoing Kit car
classes as im not up on those
CNH
CNH
"Racing is life, everything else, before or after, is just waiting"---Steve McQueen
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hobbsy
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| posted on 19/10/10 at 09:09 AM |
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I fitted a Quaife and am happy with it.
I think the retail price is about £550 plus VAT. And discounts are hard to come by (do a search on my username you'll see my failed attempts to
sort out a group buy a couple of years ago).
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bimbleuk
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| posted on 19/10/10 at 10:29 AM |
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If money is tight you'll have to find a 2nd hand Sierra viscous diff. If you want a fit and forget diff for most situations then the Quaffe ATB
will do. If you want to be able to change the locking/ramping to suit different situations then the Tran X, ZF etc. plate type diffs would be worth
considering. IMHO of course.
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CNHSS1
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| posted on 19/10/10 at 10:39 AM |
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ive used all three, and each have their own pros and cons.
Quaife is fit and forget, in normal road use you will never know its there, juts like a normal open diff. great quality and quiet if you do mileage.
Did 6 seasons with nothing more than an oil change in my hillclimber. if one wheel leaves the ground or becomes dramatically unloaded, it sends the
torque to that wheel resulting in no drive (bit like an open diff) BUT this does make it very safe and nice if bouncing over the kerbs on a hot lap!
Pretty vice free.
The viscous is cheap and plentiful although abused examples often have the VC pack overheated and the fluid loses its viscosity, leaving it less
effective than desired. The ford dealer manula gives a torque wrench test to check the 'resistance' of the clutch pack and a range that it
needs to fit into. Does effectively lock under hard acceleration (doesnt actually, but lets say it does  ) so great drive out of slow corners but can
give a little power understeer and snap oversteer if you are overly rough on the controls. ultimately its not as clever as the quaife or as vice free,
and not as adjustable as the plated types, but cheap and available.
Plated diffs have a clutch pack that preloads the sun/planet gears in the diff if one wheel tries to rotate much faster then the other. They can be
clunky and noisy in operation on a road car (depending on ramp angles and preload) and do wear. Once the friction plates have worn the
'action' reduces and will need rebuilding.
They are adjustable in their operation though. You can affect how aggressively they lock the two wheels toghether, or how smoothly. You can have them
lock on acceleration only, or also partially or fully under braking too. Often a locked diff under braking can make the car really good on the brakes.
They tend to be a bit snatchy and even violent in small light traction limited cars, but are the ultimate (if set correctly) for competition.
imho all 3 need the cars set up adjusting to suit, and will affect the driving style accordingly.
HTH
CNH
"Racing is life, everything else, before or after, is just waiting"---Steve McQueen
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JimSpencer
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| posted on 19/10/10 at 05:54 PM |
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Hi
Got a Quaife in a Striker
Competing in the road going classes of hillclimbs and sprints - perfectly OK rules wise.
Ran the car for the 1st season with an open diff, and it used to spin up the inside rear wheel with amazing ease.
Fitted the Quaife (Had it recommended to us) and it's been excellent, made a huge, positive, difference to the power delivery and handling.
Not tried either of the alternatives so can't comment on those i'm afraid.
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gml7
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| posted on 19/10/10 at 07:40 PM |
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Thanks for all the advice. It sounds like the quaife option will be the best option especially as I don't know enough about setup yet.
Read a few horror stories on some forums about diffs ruining handling with the back end becoming twitchy and letting go without warning. Is this
something that you just have to allow for?
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procomp
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| posted on 21/10/10 at 02:00 PM |
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Hi
It is correct that the 750mc kitcar regulations specifically do restrict the use of an LSD. However there is the new class within the kitcars next
year that is a virtual run what you brung purely to get numbers on the grid. The final details i have not as yet seen but from the draft copy that was
circulated i am sure LSD's where permitted. RGB is fine for using one.
As you may have gathered from above the Ford item is not really suitable for the cars and it really becomes a case of either the plate type or Quaife
ATB. The ATB unit is the best option as a fit and forget BUT only if you have the rear suspension set up to ensure that both wheels remain in contact
with the ground in all but extreme conditions IE make sure there is enough droop travel available on the dampers.
RE the plate type you need top have the unit tailored to suit with the various ramp angles to get the best from it. It will also require a rebuild and
reset once or twice a year to ensure the settings are still in tolerance once it has bedded in and been used a number of times. It is fair to say that
for the ultimate setup the plate type is superior as it can be tailored to the application but requires maintenance etc with use.
All in all unless looking for the very last little bit just fit an ATB unit. Best price is usually Burton performance. Dealing with Quaife direct is a
nightmare.
Cheers Matt
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coozer
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| posted on 21/10/10 at 04:05 PM |
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I put a Ford visco in mine and I reckon it tightened up the handling pretty good. But, I'm no racing driver....
Am I talking nutsack or what?
1972 V8 Jago
1980 Z750
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bigfoot4616
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| posted on 21/10/10 at 04:57 PM |
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quote:
Originally posted by procomp
It will also require a rebuild and reset once or twice a year to ensure the settings are still in tolerance once it has bedded in and been used a
number of times.
Cheers Matt
Matt
earlier in the year you recommended a plate diff over an ATB for my live axle striker. anyway i've decided to fit one this winter.
how often am i likely going to need to have a rebuild doing 9/10 trackdays and about 1K road miles a year? or does it depend on how hard i'm
using it
also regarding ramp angles is it just best to go with what the supplier recommends for a lightweight car like a seven or is there more to it than
that?
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procomp
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| posted on 21/10/10 at 08:26 PM |
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Hi
Yep i have over looked something in the brief explanation. If it is a live axle car especially the Striker then i recommend a plate type due to the
lack of compliance in the rear setup which leaves the inner rear wheel light loaded during cornering. This can have modifications made to make the
setup more compliant if a ATB is to be used.
Ramp angles etc assuming it's a tranex setup. It is fairly well recognised that 35/90 is a very good starting point. Preload setting are varied
to suit differing peoples applications and preferences but 40Lb is a good starting point as it will bed in and settle down to around 35-30lb which is
where most find good results. setting it at the recommended 35Lb initially See's it drop once bedded in to lower than 30Lb which is too low.
Cheers Matt
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