How would car performance be if Earth's O2 level was way higher (like 25, 50 or even 100%)?

Answer 1

Whenever more oxygen is available during combustion you can also inject more fuel, allowing the same engine to produce more power. So at 25% O2 you would probably notice a difference but not a very dramatic one being that room air is normally %21 O2. At 50% O2your car would run incredible but would probably melt your pistons fairly quickly. At 100% O2 any fuel would ignite very quickly, your car would probably be on fire before it even started.

Answer 2

It would be a little dangerous to have extreme levels of O2 in the atmosphere. But your car would have an outrageous amount of power increase! Nitrous Oxide installed on a car is an example of this-50,100,200 h.p. increase at the flip of a switch!