Always Overcharged

I have noticed an increase in how often my quattro seems to re-align the torsion when driving.
this causes an unpleasant thumping for about one second.
Is this peculiar to my car-I think not as an S8 I drove last month was doing it at every take off that was on lock.
Any thoughts welcolmed

skiwi

you mean the torsen?

Always Overcharged

yes?

Mikalai

when you drive straight, even under changing load distribution between front&rear, nothing moves inside torsen.

Torsen never locks as word "lock" mean.
Torsen works very similar like open differential. Only differencies are coef-nt of transformation: open diff has 1:1, torsen in our cars has 1:2.

Unpleasant thumping is anything else, but deffinitely not torsen "re-align".

Always Overcharged

any ideas what it may be-it is like a crabbing effect as when my olkd 4x4 was on hard lock

Mikalai

Probably EDL/ESP. There is some thump wnen that systems briefly activate one wheel brake.

skiwi

the torsen is normally "locked" as long as it is operating within the bias ratio (i.e. in normal operation). only outside of this does it lock and allow it's shafts to operate at different speeds. this is the reason that stasis and others have achieved good dividends from employing a high bias torsen in their race cars, as the better that it resists understeer...

the torsen operates like a limited slip diff, more than an open diff. it operates like an open diff when one shaft has no traction. hence the edl intervention...

in normal operation, in straight ahead driving, the torsen will allow a static torque bias that mirrors the weight distribution (in other words the traction distribution) of the car - not 50:50 as you might imagine, but closer to 60:40...

based on the discription supplied it is impossible to provide a diagnosis. is the "thump" you reference on full lock, or in the straight-ahead?

Always Overcharged

Generally it occurs at slow speed after having been on firm lock

skiwi

have you got cuts in your boots?

Always Overcharged

no all fine