Dear Everyone,
Here it is at last!
Default values are for a standard GT6, change them to your own.

1/    You can alter the value of any BOLD cell to your preferred value. The
first page contains the main variables. All cells that are not in BOLD are
protected against accidental change or erasure. Unprotect the document to
make any changes to these cells (Be Careful!), leave the document protected
if you only change the BOLD cells.
Rolling resistance & Air resistance can be left as is or estimated for a
different car by using the second table. This table calculates the time
taken for a car to decelerate between two speeds using the two above
resistances.

2/    The table to the left of the first graph is the main HP curve for the
calculations. The BOLD HP column can be altered to suit your car or you can
guess values until the curves look correct.

3/     The first long table gives the calculated time versus speed. Any BOLD
value can be changed and everything will re-calculated immediately.

4/     The last table gives an estimate of the HP needed for any particular
speed, again using the resistance figures from the second row.

5/    You can alter any figure in BOLD and that change will be reflected
throughout the spreadsheet. Keep a security copy of the spreadsheet as sent
as it is very easy to screw up the formulae by mistake by writing in the
wrong place. Main thing not to do is move the position of the HP chart at
the top of the first page as all the calculations are referenced to the
absolute position of the Torque(net) column!

6/     I have made several reasonable assumptions and approximations, (I
think!). I have started the acceleration table from 20 mph and 2.5 seconds
as It is impossible to model clutch slip. For powerful engines and/or low
ratio diffs you could change the start time to 2 seconds. I have allowed a
time wastage of 0.5 secs for each gearchange. You can see these as little
plateaux in the curve.

7/    I am sorry that the size has grown to over 300K, that is because it
now handles the full set of gears with automatic gearshift at max rpm
whereas before it just did one gear at a time.

Try it out, tell me what you think. Change it if you want, it's only a bit
of fun.

Peter French.