I tried out the suggested values of gadagaseng and was still not quite happy. I have driven racecars with sequential gearbox in reallife and was missing that kind of shifting-experience in nfs shift. So I tried to tweak the values a little more and found the "SemiAutomatic" value. I wanted to "simulate" a real race gearbox which cuts the ignition if you shift, without any clutch activity. If you set Semiautomatic to 1 you get auto-clutch which is bad but atleast you dont hit the limiter everytime you upshift (best seen in low rpm) -> ignition cut.
So in the end I did the following:
SemiAutomatic=1 // whether throttle and clutch are operated automatically <- set to 1
UpshiftDelay=0.10 // delay in selecting higher gear (low for semi-automatic, higher for manual)
UpshiftClutchTime=0.00 // time to ease auto-clutch in AFTER upshift (0.0 for F1 cars) <- set 0 to disable auto-clutch
DownshiftDelay=0.50 // delay in selecting lower gear (low for semi-automatic, higher for manual) <- default value
DownshiftClutchTime=0.00 // time to ease auto-clutch in AFTER downshift (used to be SemiAutoClutchTime, note that the
shift will complete significantly before the clutch is fully engaged) to disable auto-clutch <- set to 0 to disable auto-clutch
I think it comes much closer to a real sequential racing gearbox. At least in upshifts
edit: i even decreased UpshiftDelay to 0.05. Ill try to get real values from such a gearbox...