Launch control.

[dtpearson]

You don't need to keep it in a rev range, you just flat the accelerator with the brakes held on. The revs will sit at 4000RPM until you release the brake. Then WOOOOOOSSSSSSHHHHH!

[jonoz]

As above, just keep your brake and accelerator planted to the floor and when you want to go (pointed in a safe direction) release the brake.

Generally I will shift to "Race" if launching, not sure what minor increase the DCC extra stiffness will give you but I am sure it is there.

[sergioscirocco]

capital R perhaps this video will help in the sec 28.