[hl0m4n]

what happens to the dsc,traction, etc after the dsc is installed? do you rest the ecu so it can relearn and adjust to the new lsd? warning messages errors?

just curious what happens to the configured dsc after installing the lsd in although yea the ride is 100% better

[cstavaru]

My opinion is that the DSC system cannot really detect the presence/absence of a different differential type. It sees the differential actions on the wheels just like grip variance conditions which the road has on the wheels. So I expect the DSC to behave fine in the presence of a LSD, not needing other algorithms to work correctly. But I am sure that if BMW would offer a LSD as a BMW Performance option, the DSC system would have to be recoded in order to take full advantage of it.

[GeorgeSmooth]

All I noticed when I had mine fitted was that the light flashed far less. The DSC does not learn or adapt to anything. Its not like that because road surface is not really constant. It works on a action reaction basis using the ABS sensors for slip measurement. With the LSD you will have far less spin on the inside wheel in corners thus creating less necessary intervention. Similar things happen on a straight with the less slip.

[meyergru]

No, DSC cannot detect the presence of a LSD. There is no adaption, either.

I heard that with locking diffs (like the original M diff) DSC and more notably, ABS, need certain modifications. At this time, there is no option from BMW to modify/adjust them for non-M cars, BTW.

With a torque sensing diff, no modification of DSC should be neccessary (this applies to ABS as well, since a Torsen-style diff acts as an open diff when no power is transferred), although the effect of the LSD could lead to a later reaction of the DSC:

Imagine a situation where you would break traction without the LSD on just one powered wheel, like in a turn. The LSD will keep the diffference of the speed of both wheels at bay, unless you break traction on both wheels. Normally, with an open diff, the inner wheel would be braked by the DSC. With a LSD, DSC does nothing since it cannot detect that situation any more.

On the other hand, the final break of traction at both wheels occurs much later with a LSD, but the margin at which the DSC could intervene more subtly is eliminated.

Look at it like this, there are three possible states:

A. Both wheels have traction.
B. One wheel has more traction.
C. No wheel has traction.

With an open diff, this is much like this:

less <---------------------- torque at the wheels ------------------------> more
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCC
no DSC intervention            DSC brakes one wheel       DSC reduces throttle

With the LSD, it is like this:

less <---------------------- torque at the wheels ------------------------> more
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCCCCCCCCCCCC
no DSC intervention            LSD does its magic         DSC reduces throttle

I doubt that there can be done very much about that by modfying how DSC works. This is a trade-off: You can go much faster with a LSD, but when physics sets in, the result is heftier than without it. I deem this effect desirable, but YMMV. In winter conditions, you should be aware of what can happen.

So, you can say, the borderline for the DSC (and you!) gets thinner. It might also be more difficult to detect the complete break of traction for DSC. Thus, if you push it too hard with a LSD, swing of the tail will be more violent as a reaction to power oversteer than with an open diff.



P.S.: The ony situation where DSC would brake one wheel with a Torsen-style diff would be the infamous "one wheel airborne" case when one wheel has no traction at all and the LSD acts as an open diff.

[335iheLLraiseR]

only thing i heard and this was a while back, was that someone that installed a Quaife as well as a 3.40 diff from an auto onto a manual car, the dsc wouldnt work properly.

working fine now though.

[Hit_Apex]

Originally Posted by 335iheLLraiseR

only thing i heard and this was a while back, was that someone that installed a Quaife as well as a 3.40 diff from an auto onto a manual car, the dsc wouldnt work properly.

working fine now though.

I have this setup without any problems. I rarely use DSC though unless it's raining.

[335iheLLraiseR]

Originally Posted by Hit_Apex

I have this setup without any problems. I rarely use DSC though unless it's raining.

you actually disable it everytime you get in?

[orionredwing]

Like the others said, nothing actually changes w/ DTC/DSC. It's just that w/ LSD, they engage far less during acceleration and cornering.

My experience with hitting DTC button once - since LSD causes the car to lose traction later, the DSC jolt that happens in the end was very surprising and didn't feel very good / smooth.

Because of that, I typically drive at the default ON. With DTC ON, traction control still triggers far less frequently, and when it does trip, it's predictable and smoother.