LSD.... A mind/body experience

Turning the ASC off leaves that bloody annoying orange light on the Dashboard. I also must admit that with close to 2 tons of metal, and the fact that a set of rear tyres seem to last for about 6,000 miles with the ASC on then I would need to be persuaded bloody well to turn it off.

Remember, the 8 ain't a sports car. LSD or not if you are grtting the motor into the kind of position where you reckon an LSD helps you round bends then you're probably exceeding the design parameters of the car.
Not to mention being a total liability on the road.

Hell. it's almost 2 tons!! If you really believe that a n LSD system works as well as you claim then I can't see you you getting more than 3/4000 miles from a set of rears. I'm only getting about 6,000 from rears without knocking off the ASC.

I've had the arse end sliding many times, but luckily the ASC system has channeled it well.

With the sheer weight of one of these things there is no way that I would want to explore the definitive limits onpublic roads.

I've had a fair share of powerslides wiht my 8 in roundabouts and such (ASC off mind you), and if there is one thing I've noticed it's that this car is very controlable when going sideways. If the back end kicks out its very easy to control it back again.
I've had other cars in the past that needed alot more work to get back straight and with a nasty kick the other way, but not the 8, it just gently gets back straight, and the only thing that shows that you've done something out of the ordinary is the smoke trail.
I find this 2 ton car very easy to drive and handle, it's not a go-kart, but sure dont act its weight.

I think were all getting a little carried away now!

An lsd isnt all about power slides, we all know that the cars ASC system has some flaws so a lsd helps smooth them out,any way when i converted my car to the M5 3.91 it wasn't to gain the limited slip ,just the ratio, so happens the M5 diff is LSD, but it is nice to lay twin stripes on the road when the mood takes

Carried away?? noooo...

Well a LSD will make a car much more controlable than a standard "open" diff in sideways motion.
However the rear end will come harder and easier with an LSD.

The major advantage is when powering through corners a LSD car will "set" the rear end and all the power will propell the car forward, uness the power is so great that both rear wheels will loose traction.

A non LSD car will most lightly start to spinn on the inner wheel because the weight shifts over to the outer side, and the cars rear end wont "set" in the same way so accelleration will be less because a lot of power is wasted on the inner wheel spinning and less power is on the outer wheel.

Inner wheelspinn won't necessarily make the rear end slip away.
On a LSD both wheels will spinn at the same time and the rear end will slip away.

Sorry for the lecture guys

And Steve, the gear ratio makes all the fun don't it

I thought that standard BMW LSDs are only 25% locking, which is very minimal LSD action. Also, for cars fitted with a standard-fit LSD, the ASC is generally modified to be a little less intrusive.

A 25% LSD is standard on BMW, for normal driving you don't need anymore.
On a track day even a 25%LSD will give you inner wheel spin, but this is in very hard corners, and it's a lot less and a lot later then inner wheel spin will occur on a non LSD.

more than 25% is quite enough for normal use, and I would not recommend more than 35% on a everyday road vehicle. the higher the % is the more strain you put on the drive train, drive shafts, wheel bearings and tires.
A 100% is the equivalent to a rod with two wheels on, try and turn one and you will find it hard.
In a normal turn the outer wheel rotates faster than the inner one because it had a longer distance to travel, the higher the LSD % is the more like the rod it will be.
I once was as a passenger in a car with a 75%LSD, in every bent you could hear the trivet rain being strained, and the car would rather go straight forward then through the bend, you almost had to kick out the rear end and power slide through every corner.

When it comes to the ASC, remember that this was the first ever system BMW developed, the newer DSC system is a world apart.
Currently only the M models have LSD, and some Z3 also had it. so since 1995 no normal BMW has had LSD fitted or as an option.

However, there are some good news, BMW had developed a new LSD and will make it available for all models in the future.
The system is called Dynamic Performance Control

"Dynamic Performance Control is based on a mechatronic system that takes over variable distribution of drive torque to the rear wheels independently of engine power. The difference in torque can be as much as 1800Nm and this enhances handling, steering precision, directional stability and traction. At the same time, the steering responds more directly, needing fewer steering corrections and stabilising interventions from the electronic control systems, such as Dynamic Stability Control (DSC). "

link to article http://motoring.iafrica.com/newsbriefs/653507.htm

This will be a variable LSD, like the ones you can buy from Quaife, only much more complex, and looks like it's electrically controlled like on the later M models, only a further development.

Noggie,

I see you hve good knowledge of LSDs. I thought that the locking action of the LSD is also speed-related, not just difference-related, such that on low-speed corneringthe LSD does not come into play.

I've driven 4x4 with locking (100%) diffs on the two axles and centre diff. Certainly, locking the rear axle causes a lot of torque wind-up on dry, hard-surfaced roads and if you try that with the front, then you certainly don't go round corners.

Arnie.

A 25% LSD will alow a 25% speed difference between the two wheels.
in a normal turn the difference is far from 25%.
when i.e one wheel on tarmarc and one wheel on gravel the gravel wheel will have less friction and will spin, without a LSD all power will go to the spining gravel wheel an next to noting to the one on tarmarc.
with LSD a maximum difference of 25% between the two wheels is achieved, hence the tarmarc wheel will have plenty of power and you will accelerate almost like normal.

LSD = Twin stripes on the tarmac

Zitat von Noggie

Arnie.

A 25% LSD will alow a 25% speed difference between the two wheels.
in a normal turn the difference is far from 25%.
when i.e one wheel on tarmarc and one wheel on gravel the gravel wheel will have less friction and will spin, without a LSD all power will go to the spining gravel wheel an next to noting to the one on tarmarc.
with LSD a maximum difference of 25% between the two wheels is achieved, hence the tarmarc wheel will have plenty of power and you will accelerate almost like normal.

Noggie, so by that example, a 35% LSD will allow 35% speed difference and a 100% LSD an 100% speed difference....

I think what you mean is that a 25% locking LSD will allow 75% speed difference or slip...

the comments below the video are almost as fun!

Zitat von Noggie

Arnie.

A 25% LSD will alow a 25% speed difference between the two wheels.

Have to correct myself here, wrote this in a hurry as I was leaving work last afternoon.
The correct value for a 25% LSD is 75% difference in speed between the two wheels.
So in the scenario I explained in my last post the maximum difference is: 25% power on the tarmarc wheel and 75% on the gravel wheel with a 25% LSD

Sorry, my bad.

whell spinning

hi, I am trying to post a small clip for you all. When I add the attachement the system sais : "The Extension avi is not allowed"
What do I have to do to post this clip ?

Thanks

clip

Ok I see. Well, I don't really wont to put it on Youtube. It was a little burn out clip with a positraction differential. Thanks anyway TallTony.

I take it this one would be okay aswell

http://cgi.ebay.co.uk/ws/eBayI…em=130103071969&rd=1&rd=1

I have been told that the only E34 differential that works is the '91 M5

The rest are small cases like the E32 6 cylinders.

That could be US only but .......