I was having a look at some onboard videos during the launching of the cars off the grid. One in particular I have is Schumacher taking up his position on the grid this year in Monaco after the warmup lap. Approaching the grid, he warms up the tyres a little, comes off the power, presses the "N" (Neutral) button at the top left of the wheel and stops. After idling for about 20 seconds, the first red light comes on and he presses the "OV" button right below the neutral button. Simultaneously the revs rise to what sounds like 11 or 12,000rpm. Then the engine makes this grumbling sound for a few seconds before the car is away. I'm wondering what the OV button is? Does this button put the engine at a pre-determined RPM for launch? It's in the same position that the over-rev button was on the Ferrari steering wheel used from 1999 - 2001; the purpose of this button was to reduce the maximum RPM to conserve the engine. Also, why does the engine start making the grumbling noise 3 - 4 seconds before leaving the grid? Is this the car being put into 1st gear but with the clutch held in?
I think the off song noise you are hearing is simply the computer controlling the optimin revs for the start. They appear to control engine revs for traction control via spark limiting which makes the engines sound off and thus I guess they are using the same process. Pete's guess
I think the "grumbling" is the engine softly bouncing off the rev limiter several times a second before the clutch is released.
Yes, you are correct. It is similar to the grumbling sound that comes in when they take a pit stop. You have seen the "lolipop" Man with the sign on a stick show the driver put the car in 1st gear, right? So the car is then put in 1st gear but the clutch is held in. This is what creates the grumbling sound. As for the OV, it is the over rev or optimum rev button. I think this brings the engines to the optimum rpms best suited for the start.
