09-14-2004, 01:27 PM
what are the #'s you're using Mike? The site makes no explanation, but I think we can assume it's wheel HP, here's why:
A more basic calculator is here for comparison:
http://www.gtechprosupport.com/support/AeroDragCalc.htm
HP loss due to aero drag = (Cd * Area * Velocity^3)/150000
So in my case, at 116MPH, I'm out 68.7HP due to aero drag alone. I think in this equation, it only makes sense to consider HP at the wheels. So with JUST aero drag, I should be able to go only 121MPH. Obviously the calc you posted Mike takes a bit more into account since it brings in the weight. So it's probably added some stuff onto this basic equation. But if I assume crank HP with the more complex EQ, it says I can go 128MPH! Not likely. At the most, I should be able to go 121. So I think it's wheel HP for the more complex one too. Make sense?
Oh, and this simple calc page has a link to a LOT of front area and Cd info for a bunch of cars! Sweet! (unfortunatly not much within the last 10 years though)
http://www.teknett.com/pwp/drmayf/tbls.htm
As another point of reference, the more complex calc says my E36 could go about 145, which is about right from what I've heard and what I almost saw at Lowes. 8) But if I assumed crank HP? It says about 160. No way. (E36 #'s I used, .32Cd, 21ft^2, 3150LBS)
So Mike, all in all, I call BS. Your hatch can't go 145.
oh, and John! 30ft^2? What, is then when towing? :lol: You should be using ~20 as well. You should be able to go 168. :mrgreen:
A more basic calculator is here for comparison:
http://www.gtechprosupport.com/support/AeroDragCalc.htm
HP loss due to aero drag = (Cd * Area * Velocity^3)/150000
So in my case, at 116MPH, I'm out 68.7HP due to aero drag alone. I think in this equation, it only makes sense to consider HP at the wheels. So with JUST aero drag, I should be able to go only 121MPH. Obviously the calc you posted Mike takes a bit more into account since it brings in the weight. So it's probably added some stuff onto this basic equation. But if I assume crank HP with the more complex EQ, it says I can go 128MPH! Not likely. At the most, I should be able to go 121. So I think it's wheel HP for the more complex one too. Make sense?
Oh, and this simple calc page has a link to a LOT of front area and Cd info for a bunch of cars! Sweet! (unfortunatly not much within the last 10 years though)
http://www.teknett.com/pwp/drmayf/tbls.htm
As another point of reference, the more complex calc says my E36 could go about 145, which is about right from what I've heard and what I almost saw at Lowes. 8) But if I assumed crank HP? It says about 160. No way. (E36 #'s I used, .32Cd, 21ft^2, 3150LBS)
So Mike, all in all, I call BS. Your hatch can't go 145.
oh, and John! 30ft^2? What, is then when towing? :lol: You should be using ~20 as well. You should be able to go 168. :mrgreen: