You can simulate this, to some extent
Use excel or some other spreadsheet type application.
Here's the info to collect on the vehicle(s) you want to "race"
dry weight
peak torque
final drive ratio
all gear ratios
tire size
driveline loss factor, if unknown 15%
tire size (i.e. 225/50R16)
now, here's what you can do. setup the gear ratios 1-n as rows in the spreadsheet, in column A.
for Column B, take the final ratio times the cell in column A. That is your torque multiplier for that gear.
For column C, take column B times the engine peak torque
for column d, take column C times (1-driveline loss factor)
column d will be the corrected torque delivered to the drive axles, in each gear
using the tire size information, you can figure out the rolling tire diameter. this formula is on the internet, but it's something like this -
diameter = wheel diameter + width * aspect ratio
the problem is that width is given in MM and diameter is in inches.. and this is the diameter of the total wheel.
what you _want_ is the rolling wheel+tire radius in feet. For now, substitue 1.0, as most rolling wheel assemblies have about a 1 foot radius.
for column E, divide column D by the rolling wheel radius you calculated.
that is the torque you are delivering to the pavement in each gear.
for column F, take column E divided by the vhiecles weight. That is the delivered torque-to-the-ground divided by weight ratio.
the torque to the ground is how much FORCE you are pushing the car forward with. the WEIGHT of the vehicle ultimately inhibits how much acceleration you can get (F = ma).
In column G, take all the values in column E divided by HALF of the vehicles weight. This is _roughly_ the torque / weight ratio to the DRIVE wheels. This assumes a 50/50 weight distribution, which wont be the case for most cars (unless we're talking BMWs) and only matters at acclerative rest, since the weight distribution changes front to back with acceleration or decelleration.
after you've done all this, you've got a good idea of what percentage of the vehicles weight the vehicle is pushing to the drive wheels, in each gear. This number is roughly comparable to what you should expect for acceleration. If you get a value > 1.0 in column G, you should expect to be able to spin the tires at the torque peak in that gear.
if you do this for a few differnet cars, column f and G should be an accurate comparator of the cars acceleration. The problem here is that this completely ignores horsepower, and it uses a fixed torque value (the torque peak) instead of integrating along the torque curve. This model is only accurate if the vehicle is near its torque peak the entire time it is accelerating. This depends on the engine and gearing of the car in question.
the number in column G is roughly the "pull" of that car in that gear. If you find that some other car is 10% or more higher than you in each gear, expect them to beat you until at least 80mph or so, when aerodynamic effects become significant.
let me know if anyone has any questions.
oke: for the rest of my life!!
