[qbix]

Hi Guys!

Got Quaife upgrade on my 335i some time ago.

The car is fun to drive now

I wanted to ask you if it's normal that when I loose traction on 1st or 2nd gear (hard acceleration) the real of the car always slides to the right? Is it due to the torque biasing or it's not being transfered to the rear wheels equally?
Otherwise the car tracks straight.

Thanks!

[CJ421]

First of all, nice upgrade, congrats!

Did you change the subframe bushings? The stock ones allow the subframe to twist around and you'll effectively have torque steer. Look into the M3 ones (labor is kind of expensive) or at the very least doing the Powerflex inserts, though I have no experience with the latter.
Also look into getting adjustable rear toe arms. I have the Rogue Engineering ones and they are excellent. They'll keep the rear toe in check.

Those two upgrades will help keep the rear end planted.

[qbix]

Thanks!

I keep stock bushings like the rest parts of the suspension (M version).
I read threads about suspension upgrades but I don't understand why it happens only when the rear tires loose traction. Otherwise the car tracks straigh!

[CJ421]

Does it happen with just you in the car? If it's only when losing traction, it could be due to uneven weight side-to-side. The side with less weight will break loose first. I am not sure if that'd be enough to cause the issue you are seeing.

[qbix]

To be honest I haven't checked that with another person inside.

Could it be due to construction of LSD? It's Torsen and as far as I know it would never lock 100%. The crown whell in the pumpkin is on the left side so this side should loose traction first (if surface condition is somehow uniform). I don't know if it makes any sense .

[Chowbow]

If you're talking about the rear sliding while the rear tires have lost traction (in a straight line), it's because of the way the driveshaft rotates in that direction. I can't remember the specific reason it does that, but I recall reading about it and how the driveshaft rotation and how it mates to the differential makes it do that.

[stressdoc]

Mine also starts to drift right initially but then oscillates left/right a bit. Two clean black lines of rubber though. I think tires wear a bit differently because of this.

For some reason I have always been a little bit more comfortable power drifting to the right (car turning left, rear end going out right). Not sure why. Same with a motorcycle, I prefer my left leg down.

[will.c]

My rear end also turns slightly to the right side under hard acc. (RWD 6sp with no LSD)

[qbix]

Before I installed LSD the car behaved same way but I can't remember if it was more pronounced.
Any ideas?
I doubt that changing the bushings, sway bar and the toe links would change anything.

[nitehawk]

Interesting, I wonder what you are experiencing is the same as the OP in this thread?
http://www.e90post.com/forums/showthread.php?t=687124

Are you referring to that squirmy/squishy feeling just after the onset of WOT? I don't have LSD, the rear does move side to side in the first two gears. However, it's not enough to steer me out of my lane and definitely not while downshifting into 3rd on the highway.

[qbix]

No, I am not experiencing the same thing what DaFish describes in his thread.

My car tracks solid straight as long as there is traction. Once the rear looses the traction (like wet road or very hard acceleration), the rear always skids to the right first. Then of course depending on your corrections it settles in straight line or just swings a little.

As I experienced the same effect without LSD, I assume it's normal. It must have something common with physics of the final gear. I am wandering what causes this effect?

[cleex024]

what causes this is the drive shaft turning with all that force in that direction...think about you holding a drill and drilling it into a concrete wall. there is a lot of torque and if you get caught up on something it will force your body to the right...same thing.

of course the way im explaining it is very simple...there is a very technical way to say all this but im no genius and dont know the specifics =)