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Old 28-07-16, 22:45
RobertT RobertT is offline
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Originally Posted by grahamb View Post
They always looked after me. A plate diff is what you need from the sound of it. The ATB is really meant for fast road, not race in my experience.
SR8 has an atb diff as standard and goes pretty well....and is certainlly a bit racey
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Old 29-07-16, 01:17
Darvie Darvie is offline
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Hi Steve,
We had the same response when we owned the Jedi, free of charge and no postage, cannot ask for better than that.
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Old 29-07-16, 01:32
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Originally Posted by RobertT View Post
SR8 has an atb diff as standard and goes pretty well....and is certainlly a bit racey
Indeed, being a properly racey car it has a properly low CoG & thus little weight transfer as do the Jedis, Radical & Lola in earlier posts.
Lots of others such as Clubmans chassis cars & some single seaters with Hewlands don't have LSD's at all because they hardly need them.

Sadly this advice doesn't much help if you want to race a Beemer. The amount you can lower the CoG is going to be pretty limited by the regs.
Apart from that the only other thing is soften the rear or stiffen the front so it waggles a front wheel in the air rather than a rear one.

Even so there is going to be significant weight transfer with the inner rear slipping more than the outer one (even if the inner doesn't leave the ground).

Isn't this slip what the ATB senses? I don't think it stops biasing the torque if the inner wheel leaves the ground & spins too much, it just can't bias it any more than a fixed percentage.

Maybe a plate diff would be a better bet. I really don't know but Quaife must as they produce both plate & ATB diffs.
Is there ever enough run-off?
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Old 29-07-16, 09:59
wombat58 wombat58 is offline
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Google Quaife ATB's. They stop biasing when a wheel lifts, and go open. It is a known feature of ATB's. You need a plate diff, full stop.
Stephen Hooker. Mk.4 Jedi / Suzuki GSXR1100W, EFI turbo
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Old 29-07-16, 10:25
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CNHSS1 CNHSS1 is offline
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Or change the car setup to suit. If it's lifting a wheel enough to 'diff out' an ATB then you aren't going to go any quicker with a plate diff. The cars setup is off, a plate different will just cause bigger slides with one wheel in the air.
If you do go plated diff, do your homework first. Do you want it locking on power, so open under braking, locking under power and braking? How much pre load and what ramp angle. A badly setup plate diff in a wallowy car will be more difficult to drive than a quaife for definite
I'd say improve the cars setup first before junking the ATB
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Old 29-07-16, 21:19
MikeBeattie MikeBeattie is offline
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You need to make your car more compliant at the rear, softer rear arb or disconnect the extg for starters. I had a Quaife in my 240Z and it worked fine in the dry and wet on Ulster hills, so you just need to play with your rear suspension settings.

Ultimately, as folks have said a Gripper is an excellent diff, and maybe you should have gone that route, but you can make your Quaife work better.

Make some changes and let us know how you get on
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