Thread: ABD vs LSD
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beepbeep beepbeep is offline
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Join Date: Jun 2001
Location: Sweden
Posts: 5,756
Originally posted by smdubovsky
Thats only half right. A cluch style LSD has to transfer torque though the spyder gears too. The "grip" side clutch pack will transfer torque directly, while the "slip" side clutch pack will transfer the torque back though the spyders to the "grip" side. Since both packs have the same normal force from the ramps, the effort is always split 50/50 between the packs.

Technically if you can get the diff to lock up 100%, then there is no frictional loss. But, thats not practical. The LSD is also eating up power everytime you corner where ABD has no parasitic loss until slippage occurs (which by definition means you have more power than you need, so a little loss in the brakes isn't so bad).

The best of both worlds (for accelerating) would be a quaife ATB and some form of ABD to kick in when your on ice or in the air (curb hopping). In a Hummer H1, you get to do this manually by left foot braking while rock climbing (it has quaifes). Thats easy to do since they are all automatics

ABD works pretty well for being esentially free. It doesn't have the advantage on decel like a real LSD has, but it also doesn't have the low speed chatter or rain/ice decel pecularities because of this either.

For racing, use an LSD. All stock cars w/o an LSD should be equiped w/ ABD - unless they royally goof up the programming like RallyJon says w/ his audi. IMHO, *ALL* cars should have some sort of LSD option from the factory - particularly all FWD cars that have crappy traction to begin with

Hmm...when I think about it more, you're right!

I personally don't like ABD but I only drove FWD cars equipped with it. One of things I remember well was smell of overheated brake pads after driving SAAB 9-5 Aero agressivly trough snow. I didn't brake much, just accellerated hard trough snow which triggered lot's of ABD work.
Thank you for your time,
Old 10-13-2005, 01:03 PM
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