High Speed Stability Question

[geeyore]

Originally Posted by Ryan N

Good morning gentleman,
For those of you that live in Germany, attend track events, of generally make bad decisions on public roads; what has your experience been once you get deep into the triple digits?

Not in Germany but I do track it quite often (>15 days/year) and regularly do 125-135 every lap. Aside from the noise of the windows being open (required for track in USA), it is very stable at 100+ MPH, although IMO it starts to feel a bit lighter due to aero (like any car). I guess the notable thing is the suspension is a bit soft as I believe it's designed for run-flats and regular street use. I don't know if run-flats are required in Germany but the USA suspension design seems to revolve around that idea, even on the ///M Sport. So.... in hard braking from 3-digits (threshold braking) there is substantial nose diving and a light rear-end which requires a bit of finesse. Actually it's more a matter of keeping the steering straight in hard braking, but that also would apply to any car. I'm upgrading the suspension with shocks/stiffer springs/bushings soon, but again this is for track purposes. Finally, the 135 has zero problems getting up to and operating at 100+ MPH. In my own case, 100 MPH = 4th gear at 6,000 RPM, and you've still got two more gears to go.

[MAMSport]

Recently purchased a 2013 128i M-Sport with suspension upgrades (M3 subframe bushings, control arms, upgraded ECS sway bars) and low miles. Will post new message when I am able to do so. To me, the car seems a bit 'floaty' at 80 mph, certainly not as buttoned down as the '02 M3 I am going to be selling.