Corrected entry: Nitrous oxide is not activated like a turbo boost on a video game. You switch it on before the start of a race and it is activated at a specific throttle position. Drag racing isn't a chess game where you have to trick the other driver as the last second to win.
BaconIsMyBFF
11th Aug 2004
Correction: The button on the steering wheel is used to activate the nitrous system's second stage. Brian does in fact receive a notice that stage one is complete.
This doesn't address the mistake. The mistake in the film is that the drivers use nitrous like a turbo boost in a video game, where it is used at just the right moment. The film implies that knowing when to use nitrous is a skill that is learned through experience. Tran and Toretto both demonstrate this. Tran even says "Too soon, Junior." when he's racing Jesse, implying that if Jesse had more experience he would have known not to use his nitrous early. This is hilariously false, as nitrous oxide is used for the entirety of a drag race to boost the engine's overall power. The point of a drag race is to get to the finish line first, there is no way you would "hold back" your engine power and use the boost at the last second to overtake your opponent. If you had been using the boost for the entire time you would get to the finish line faster. The film implies this is done because nitrous is dangerous and if you use too much your engine will be destroyed, which is also ridiculous.
BaconIsMyBFF