I remember reading this somewhere and it actually works…
All you need is a car and a stop watch, if I remember correctly
You keep the car in 3rd gear (5spd) and accelerate and time it with the stop watch until red line, then you shift into neutral and roll back to your starting speed to measure the rolling resistance. You then plug a bunch of numbers into a formula and you have your cars HP/TRQ
Again, I’m not sure the exact steps but I remember reading this somewhere, anyone have a link to the site which explains how to do it?
you forgot to include rolling resistance of the tires, probably have to take into account the air density to get a more accurate F resulting from air… shit if you actually know what you are doing in regards to this, but I doubt many people would want to actually sit down and do the math to this, and you might want a program like mathcad where you only have to define the variables.
EDIT: and you have to also take into account your lack of reaction times for the timing system
The math is easy. It’s just plain old freshman year kinematics. It’s getting accurate inputs to the variables that’s going to be hard. Well, naw maybe not that easy. Drag force will be increasing exponentially the entire time you’re accelerating. Time to do calculus. :hang:
If you can get the Cd and frontal area of your vehicle, the rest is pretty much cake.
Would you even have to take into account rolling friction? It’d be there on a dyno too. Well, it would for the drive wheels. So yeah you’d have extra resistance from the non-drive wheels.
