Is this when going straight, or around corners?
I find I get this same problem ONLY when I try and accelerate around corners (e.g. on-ramp/off-ramp near motorways when you want to put your foot down!)...
I never got an answer to my thread as to why this happens, but I suspect still that it was due to the electronics controlling the vehicle forces and so limiting speed while the tyres/wheels were at risk of losing traction.... as soon as I hit the straight the sound disappears and you feel a surge of acceleration. The noise in my view is the combination of engine trying to accelerate (and revs go up), but the car is limiting speed...
(I love showing this to passengers, put your car in cruise control, go around a corner where you know you would normally brake to slow down, and the cruise control takes control and slows you to a safe speed and speeds up once you are on the straight... clever tech!)
Alpine White F10 520d M Sport Auto - 8 speed Auto/paddles - 350M 18" Falken Rear/Michelin Front - Deleted Sports Suspension - SPIDER Mods
Last edited by jedpause; 01-14-2013 at 09:02 AM.
Reason: expansion of point