Dan,
I downloaded a copy of your spreadsheet -- good job! I know what you mean by
aerodynamics and top speed. In my '97 Z28 I could easily do 150 MPH in 5th,
even going up hill with the AC on, but the one time I tried shifting in to 6th
at 145 MPH, the RPMs dropped from being close to redline to about 3700. This
was too far down the torque curve and the car immediately started slowing down.
Kevin Brown
Odessa, MO
DANMAS@aol.com wrote:
> In a message dated 6/29/99 6:36:41 PM Eastern Daylight Time,
> MGTRAutoXr@sprintmail.com writes:
>
> > I just ran across a great gear ratio, axle ratio, tire size vs. speed
> > calculator on the f-body web site. http://www.f-body.org/gears/ You
> > can start with several presets (including a F-body T5) and then alter
> > tire size, gear ratios (up to 6-speeds) axle ratio and max rpm -- the
> > program then outputs speeds in each gear in 100 rpm increments -- my V8
> > MGB should be able to do 161 MPH when completed !! :-)
>
> Kevin & others,
>
> I have put together a little MS Excel 97 spread sheet to caculate these
> parameters. You input tire size, rear axle ratio, and transmission ratios,
> and the spread sheet calculates tire diameter, tire width, mph/1000 rpm, rpm
> per mph for speed from 10 to 150 mph in 10 mph increments, and mph per rpm
> for rpm ranging from 1500 to 8500, in 500 rpm increments.
>
> It also generates a rpm/mph and a mph/rpm chart, each chart including graphs
> for all five speeds.
>
> To see a sample printout of the spreadsheet, and to download a copy, see:
>
> http://members.aol.com/danmas/design.htm
>
> I think it is a neat little spreadsheet, as you can play with it and get
> instant feedback on the effects of various changes.
>
> Hope you'all enjoy it (it shows 184 mph top speed for my TR6/Ford 302 with a
> 0.63 5th gear - oh, if only I had the aerodynamics!).
>
> Dan Masters,
> Alcoa, TN
>
> '71 TR6---------3000mile/year driver, fully restored
> '71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
> http://members.aol.com/danmas/
> '74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
> '68 MGBGT---organ donor for the '74
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