This depends on alot of factors. I never let off the gas during a race or drift event, the reason for that is I keep the engines rmps at the max all the time. The reason people can take a turn at 100 mph depends on the car the set up and the apex they use to enter and exit the turns. I only use the handbrake during races and cop pursuits and only tap the handbrake otherwise you will spin the car. Drift events are another story handbrake is all I use
Thank you very much to both of your folks reply, and I will accept the solution very soon after my son tries it. It seems the things to do are a) turning with "apex", which is turning from outside to inside of a curve b) tap very quickly with the smallest fraction amount possible for the handbrake if needed and c) let go gas or press gas trigger softly inside a turn. Will try it and let you guys know.
Kingston and Jason
