CLASS RACER FORUM - View Single Post - HP Rating....F Body vs FWD Conversion Cars

Stewart Way · 11-21-2010, 05:07 PM

Don't know as these numbers really mean much but I'll share them anyway. I used these formulas. D=AxCdxVxV/410 and HP=((WxR)+D)xV/375. Used 3000 lb W,15 frontal A, .34 Cd. R was rolling resistance of .012. These work with Top Speed numbers and I realize we are not at the top speed capability of a drag car at the 1320 but anyway....
An 88 type lowered Camaro has about a 15 frontal area. A one sqft reduction in frontal area reduces the hp required to run 150 by around 6%. But that is steady state 150MPH. Since we start at zero I would think around 4% HP change per sqft would be right. A change in Cd (coef of drag) of .01 has about half the effect of a 1 sqft frontal reduction at there numbers.
So if a littler newer car has a 1 sqft smaller frontal area and a .01 lower diff in Cd it would require 6% hp less to reach the same speed.
Again, I'm not sure how these Top Speed formulas translate to an drag car but even if they were off 50% it would still mean a 3% reduction in HP can be seen with a 15 to 14 and .34 to .33 reductions in Cd and Area.

11-21-2010, 05:07 PM	#8
Stewart Way Member Join Date: Aug 2003 Location: Atlanta Posts: 476 Likes: 20 Liked 70 Times in 22 Posts	Re: HP Rating....F Body vs FWD Conversion Cars Don't know as these numbers really mean much but I'll share them anyway. I used these formulas. D=AxCdxVxV/410 and HP=((WxR)+D)xV/375. Used 3000 lb W,15 frontal A, .34 Cd. R was rolling resistance of .012. These work with Top Speed numbers and I realize we are not at the top speed capability of a drag car at the 1320 but anyway.... An 88 type lowered Camaro has about a 15 frontal area. A one sqft reduction in frontal area reduces the hp required to run 150 by around 6%. But that is steady state 150MPH. Since we start at zero I would think around 4% HP change per sqft would be right. A change in Cd (coef of drag) of .01 has about half the effect of a 1 sqft frontal reduction at there numbers. So if a littler newer car has a 1 sqft smaller frontal area and a .01 lower diff in Cd it would require 6% hp less to reach the same speed. Again, I'm not sure how these Top Speed formulas translate to an drag car but even if they were off 50% it would still mean a 3% reduction in HP can be seen with a 15 to 14 and .34 to .33 reductions in Cd and Area. __________________ Stewart Way 2424 SS