Hey Sam;
If you are traversing down a 12% grade what is your rpm at 55mph? Likewise
if you are going *up* the same 12% grade what is your rpm at 55mph?
===================='97 Dakota SLT+=====================
L. John Morris<ljohn@alltel.net>
!!!!! ... your local *HEMI* owner ...!!!!!
White/Driftwood/CC/4x4/5.2L/5spd/3.92SG/FIPK clone
soon to have "Edelbrock" cat-back
==================== Reply Separator ====================
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> From: Sam Parthemer <samp@cts.com>
> To: dakota@ait.fredonia.edu
> Subject: Re: Wind resistance; was: High Rpm's etc.
> Date: Tuesday, May 13, 1997 11:33 AM
>
>
>
> ----------
> > From: L. J. Morris <ljohn@alltel.net>
> > To: dakota@ait.fredonia.edu
> > Subject: Re: Wind resistance; was: High Rpm's etc.
> > Date: Tuesday, May 13, 1997 07:29 AM
> >
> > OK Sam here goes; (a little crude)
> >
> > >From your drive line information, (RPM's at 70 mph), your tire
> > circumference works out to be 7.1909 ft.
> >
> > At 4600 rpm / 2.86 final drive ratio = 1608.39 rpm/tire x 7.1909 ft. =
> > 11,565.78 ft/min.
> >
> > 11,565.78 ft/min x 60min/hr = 693,046.99 ft/hr / 5280 ft/mile = 131.43
> mph
> >
> > Obviously this does not take into account wind resistance, positive
grade
> > or negative grade of road, etc., etc., but it'll get you in the ball
> park.
> >
>
> I don't know what wind resistance, or grade has to do with mph at
> a given rpm... If I had a 50 mph headwind, and was turning the same rpm
> the mph would still be the same...
>
> I did a little ratio-ing and came up with similar numbers (know that
> I am thinking about it).
>
> If I turn 2275 rpm @ 65 I take
> 4600 rpm @ XX ....
>
> 65 mph x 4600 rpm = 299000 2275 x X
> ---------- = ------------
> 2275 2275
>
> X= 131.42857 mph
>
> Sam '95 SLT
>
>
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