Originally Posted by Eracer76
That's right, there are times were horsepower doesn't mean squat when it comes to top speed.
Even if there were two of the same cars, one with 700 hp and one with 900 hp and both were able to hit redline in top gear, their both going to top out at the same speed due to the gearing/rpm limit of the engine.
That's when you change the gearing to take advantage of the power produced by the stronger engine. The lower power engine won't be able to hit the rpm afterwards. Thus, the higher power engine is the faster way to go.
But it is true that if I stick a blown alcohol motor in a go cart without changing the gearing, the little 5 hp Briggs & Stratton will have the same speed at the same RPM.