Quote:
Originally Posted by Turboem1
This thread is a mess. First of all 3rd gear is not drag limited so why are you calculating horsepower and drag at 90mph? A fit can redline 3rd gear so you can use the formula for gear ratios, redline and tire diameter and ignore all the other factors. If you wanted to figure out top speed in 5th then you would need to find hp to overcome drag and use that since the fit can not redline 5th and do 180+mph
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Good points. My Fit cant redline in fourth either. And only barely in third. My Fit gains at most 2-3 mph shifting 3rd to 4th at VIR.
First the equation represented has density halved while the write up does not.
Second, dimensional analysis says lb/ft3 xft2/sec2 x ft2 leaves lbft/sec2. Thats hardly a drag dimension.
Third, where is air viscosity and compressibility considered, as well as 'inclination' and ...
It is a mess.
And max speed isn't limited by drag alone; mechanical and hydraulic losses must be included.