Difference between Traction Control and Limited Slip Differential???

[johny1]

What is the difference? For example: as far as I know ‘95 M3 has a limited slip differential and ’99 M3 has a button where you can enable Traction Control. Is this the same thing but one is enabled all the time like the 95 M3 and on the 99 M3 you can engage it by pushing a button or is it a totally different thing where the 99 M3 maybe has it both ???

Thanks

 

[andreyiv]

I am not sure if the 99 has both but traction control and an LSD are complitely different. An LSD uses clutches to decrease what the differential normally does. The LSD does this mechanically while traction control uses sensors to see the speed of different wheels and apply brakes to the wheels that spins faster. I am not sure but traction control might even monitor the front wheels and slow down the rear wheels in order to stop them from spinning an LSD only works on the drive wheels (if its installed of course). Generally it is much more fun to drive a car with an LSD and the opposite with traction conrtol. Also, it is possible for a car to have both I am just not sure about the M3.

 

[johny1]

I could be wrong about the 99 having both but does this mean that cars that have Traction Control and if you turned it off the rear differential of the car (if the care is RWD) will behave like a regular differential? Thanks

 

[Big Daddy]

Maybe this will help:

How Things Work

Traction Control

Limited Slip

 

[andreyiv]

Simply put, traction control and an LSD are two completely different things. If a car has an LSD it always behaves like it does, if it has Traction Control then it acts like it does only when its turned on. Don't get the two mixed up, although an LSD may have been an early version of traction control it is completely different and behaves completely different.

 

[carlsturm]

What is the difference? For example: as far as I know ‘95 M3 has a limited slip differential and ’99 M3 has a button where you can enable Traction Control. Is this the same thing but one is enabled all the time like the 95 M3 and on the 99 M3 you can engage it by pushing a button or is it a totally different thing where the 99 M3 maybe has it both ???

Thanks

Traction control is different than LSD, plus traction control is different than M3 DSC (Dyanmic Skid Control)

LSD applies to the rear drive wheels only controlling how fast each wheel turns primarily based on the curve radius & when a wheel slips attempts to apply power to wheel that isn't slipping. DSC monitors for skid and attempts to correct by applying braking to wheels. Traction control will cut out power in response to wheel spin. Many vehicles have traction control without any type of DSC.

 

[epj3]

Carlsturm - DSC = Dynamic Stability control, not skid.

Here's the easiest way of putting it - limited slip is a type of a differential that uses a mechanical way of keeping both wheels moving - not just the one on the slippier surface (or inside in a turn).

Traction control is electronically controlled, bogs down the engine, and applies brakes to the wheel slipping, so THEORETICALLY power will go to the other wheel through the OPEN differential. Some cars have both systems but not many new cars. Limited slip differnetials are expensive.

Limited slip makes your car much more fun. If you want to know if you have a limited slip, jack both rear wheels off the ground, put the car in neutral, take off the ebrake, and spin one of the rear wheels. If the opposite wheel spins in the SAME DIRECTION, it is a limited slip.

The more fun way to check is turn off DSC and all other BS help-me-i-cant-drive electronic systems (..hehe, just kidding), and drop the clutch from 4,000 rpm. If you lay 2 tracks of rubber, you have a limited slip. If only 1 track, then sorry!!!

 

[Wadula]

not quite, my 325 makes two tracks of rubber and i have ASC only...but that works only when both wheels have the same grip. and enough horses to get both wheels going. my old 323 did not have enough.

but good descibtion eric. i was just bragging here

 

[silvere46m3]

LSD is a set of clutch discs in the diff. itself, it makes both drive wheels spin in the same direction. traction control systems are systems prevent wheel spin.

 

[MrElussive]

The LSD is a mechanical system so it is always working. For example, if you start hard on gravel, the LSD will just transfer the power accordingly, mechanically, and quickly. I can actually hear it working on my car when I have the windows down. You still need traction control with an LSD because the LSD won't do jack if you punch it from a stop in the rain...both wheels will just be spinning like crazy until the tire gets traction.
Supposedly the LSD helps in turns, but for me it also makes the car a little bit unpredictable. If you're powering through a turn, make sure to throttle gently if you're in a lower gear (at higher revs). Too much throttle can kick the tail out easily.

One time I was driving with my friend and it was during the winter (last year) and it was really freezing cold out, about 5 degrees F. The summer tires don't really warm up below 40 degrees, and they are particularly worthless in close-to-0-degree weather. I was accelerating moderately on an on-ramp, that curves gently to the left. I was in either 3rd gear and all of a sudden the tail randomly kicked out! I twisted the wheel the other way and straightened it out instantly, but it scared the living SHIT out of me and my friend.

 

[Wadula]

i think so, but that was good driving what´s the % of your LSD?