"Because you won't explain your statement?
They can "use up more of that rear wheel horsepower", but "they won't change the amount of rear wheel horsepower"? Will = Won't???"
Yes...they will use up more rear wheel horsepower to turn them. But, it still doesn't change the amount of power your engine is making.
So....WON'T change the power at the rear wheels.
"Because higher wind resistance effects top speed? Like adding a light bar to a police car will always effect their top speed? Why do you think they continually "streamline" the light bars? You think they're looking for better gas mileage when they're in a high speed chase?"
When I said it won't make your car faster, I mean that it won't make your car faster. Numbnuts. Changing the bumper on YOUR car WON'T increase it's top speed. You don't have enough power to reach the "theoretical" top speed your car's aerodynamics is capable of. Nor is a light bar going to change the top speed of a cop car. They are too heavy and to low on power. If they were really worried about top speed, they would give them more power, not "streamline" the light bars. I think they do that so you can't tell they are sneaking up behind you as easy and so they are less conspicuous.
"Even when some Dynamometers can factor in wind resistance --before-- you get a final HP reading?"
This has nothing to do with what you're asking. You asked if changing the bumper would increase your rwhp. Not if changing the bumper would make you more aerodynamic.
Stupid. I'm done with your junior high, honda-ish logic.