MXM said:It's Limited Slip Differential.
What differential does: allows rear wheels(I'm talking about RWD) to spin individually, redirecting the power to the wheel which has less resistance. Without it, you couldn't turn, because outer wheel needs to travel bigger distance than inner wheel. But when you're stuck in mud or something, one wheel will probably get all the power, while other will stay still, that's why offroaders usually have diff-lock, which as it's name suggests locks both wheels to turn simltaneusly.
But with diff-lock you basicly can't turn (well, you shouldn't), so there's a compromise - LSD. It allows wheels to spin individually to some degree, not locking them complitely (so you can turn), but not allowing to spin complitely independent either.
It's absolutely necessary for good drift-setup for example. Or very powerful vehichle in general. So you don't end up burning rubber on one wheel only, which has little less traction, but use both wheels to accelerate.
Leppy said:A mate had one in his car. Hilarious when he backed out of parking space and the inner wheel starts bouncing up and down.
bone said:an EVO has 3 diffs
general said:LSD is good for cornering and off roading
andyhui01 said:bone said:an EVO has 3 diffs
all 4wd cars have to have 3diffs... front, mid and rear diffs...
Well....that really is a question of definition. A true 'fulltime' 4wd car like the Landrover Defender has a transfer case with a built-in differential to distribute drive torque between the front and rear axle. 3 differentials in total.adrianpike said:Wrong. 4WD cars have a transfer case, AWD cars have a center diff.
snars said:Well....that really is a question of definition. A true 'fulltime' 4wd car like the Landrover Defender has a transfer case with a built-in differential to distribute drive torque between the front and rear axle. 3 differentials in total.adrianpike said:Wrong. 4WD cars have a transfer case, AWD cars have a center diff.
A so-called 'parttime' 4wd drivetrain like the Toyota Hilux, Nissan Patrol and most other cheap terrain vehicles have, features a simple transfer-case without a diff. Here 4wd mode (either high or low gearing) means that the front and rear axles are rigidly connected, making cornering on normal surfaces as good as impossible, so the 4wd can only be engaged in true offroad conditions. In 2wd mode only the rear axle is driven.
Then there's all sorts of variations on this theme. My own Volkswagen syncro bus use a viscous coupling to engage the front wheels. Volkswagen's 4motion and some of Audi's quattro models (Golf 4 platform) feature an electronically controlled Haldex coupling to distribute power to the rear axle if necessary. AWD Porsche Carrera also have clutch-type center 'differentials'. Jeep Quadrasomething employs oil pumps to engage 4wd etc etc.
There's lots of ways to drive all 4 wheels