WHP versus crank HP

[smp3000]

Ok Ok, I'm sure this might be a lame-o question, but I've always wondered how they get the numbers for HP at the crank... I know if I dyno'd my car right now I'd probably be about 180-WHP and probably around 200 once I get to 8psi... But how does this transfer to crank HP?

Just a curious george!

 

[1sty]

Use the FM dyno numbers and see what the stock dyno run hp was then find the % loss by using the claimed 130 by mazda. Since FM got 90 HP that is a huge loss or just a bulls*** spec by Mazda. Using the same powertrain loss I got 180 whp would be 260 crank. basicly 90/130 = 180/X

 

[DooMer_MP3]

I think he wants to know how they originally come up with the crank HP (the 130HP you mentioned). I would guess they just run an engine by itself, not in a car and not bolted to a tranny etc, and measure the HP based on the speed of the crank, not wheels.

Chris

 

[dolphin]

This might answer your question. I know this was done for Corvette owners but I believe that the explainations are valid none the less.

http://www.c4vettes.com/hp.htm