This has always been a staple of the V8 games and can often get you out of a sticky situation. Simply double tap the accelerator and you'll be given a brief burst of speed - you can tell that it's worked if flames shoot out of your vehicle's exhaust.
There are a few good uses for this....
- Whenever you're at a standstill and need to accelerate, use the boost to get up to speed quickly.
- Boost up inclines that you probably couldn't normally.
- With larger vehicles, boost into other cars to increase you're ramming speed and hence, damage