LSD's

[dark_sounds]

hi people, seeing alot of mention on these... what are they?

any use to a 318is? cheers

[fuzzy]

i think basically if you lose traction in one of your rear wheels the power transfers to the other until it grips again, not an expert though so i could be wrong.

[Globulator]

LSD (non chemical) stands for Limited Slip Diff.

If you imagine having a solid rear axle both back wheels will always have to turn at exactly the same speed.
This is like a 'diff lock' on a 4x4, and will make the tyres shriek when you turn a sharpish corner).

A regular (slip) diff has a ring of gears between the wheels so one can turn regardless of the other. The ring is then driven over (like flipping a ring) by the crown wheel cog to drive the car.

An LSD is part way between, so there is some joining of the two tyres (via a fixed clutch) but not enough to get shrieking tyres. To see if a car has one and it is working you can chock the car, put in neutral with no handbrake, them jack up both back wheels and see how well connected they are. They should feel well connected as they have a big engine and one car to deal with.

[dark_sounds]

so the 318is? doesnt have one? and one cant be put on or can it??

thanks for the explanation

[chu346]

The 318is could have one, but I doubt it. More than likely has a normal diff. You can swap it for a LSD tho.

[Dan318-is]

the 318is came with an open 4.10 diff as standard

it had the ultra rare small case 4.10 LSD as an option but ul be lucky to find an IS with one on, although i was!!

you can use the 3.91 LSD of a 325i sport just, although it does sacrifice a wee bit of accelertion im told. thats really as low as you can go though!

[astondg]

Like people have said an LSD will allow a little bit of slip (difference in speed between the two rear wheels) so you can go around corners and stuff but as soon as there is too much slip (starting to wheelspin) it kind of locks both wheels together so then to get wheelspin both wheels have to spin which means you have more grip. When it does break traction it will go sideways more quickly than an open diff because both wheels are spinning.

Aston