munsabin

So I've noticed that when I'm stuck in slow moving stop and go traffic, if I don't actually stop, but just break slowly, release my foot off the break and then a second later accelerate (not hard), i feel like there's a weird gap, ever so slightly, where it's as if the wheels have wiggle room. Maybe it could also be the ECU not expecting to accelerate, and then I do Very hard to describe, sorry. There's no sound attached w/ the event but I feel just a bit of a jerk action from the car.

I haven't really put too much thought into it cause I've seen it with other cars too... but was just wondering what this is.

BiscuitEmbryo

I've experienced it too, quite a few times. i just chalk it up to an issue with the DSG transmission since it only seems to occur in the situation you described. I've wondered if one of the dogbone transmission mount inserts would help with this, but then where would those vibrations go?

up-n-coming

1. Long story short the DSG anticipated the next gear change wrong so you get a jolt.
2. DSG (dual clutch) transmissions don't have torque converters so they are always engaged so there is never any slippage (up to 500 milliseconds) in conventional torque converter automatics deciding which gear to be in .

The DSG is actually two transmissions. One takes care of the even gears the other the odd gears. If your in 2nd gear in traffic the second transmission intuitively thinks the next gear will be 3rd so it has already engaged third and is ready to switch to it in blindingly fast fashion (10-50 milliseconds) that DSG is known for. But when you quickly lift off the accelerator and get back on hard you fooled the DSG so it (second transmission) has to jump out of 3rd and engage 1st. That sudden disengagement and then engagement (remember so slippage ever) causes a jolt.

I'm no engineer but that's how it was explained to me.

Moral of the story. Telegraph your moves in traffic so the DSG doesn't get caught anticipating the wrong gear. Smooth with the accelerator in traffic equals smooth shifts. Hard to do I know!


Milliseconds in the real world:
Stub your toe and it takes approx 200 milliseconds for your brain to register the pain.
***** your finger and it takes approx 100 milliseconds for your brain to realize it.
Pinch your earlobe and it takes approx 50 milliseconds till your brain registers it..

munsabin

thanks lads

VipinLJ

That weird gap is the dsg lag I keep talking about and the only thing that can fix that issue is a TCU tune.