List members---There seems to be some interest in what it "takes" to
reach a given Elapsed Time for the quarter mile.
For the next few days I'll be including the formulas for determining
such tidbits as "how to determine your 1/4 mile E.T." when you know the
horsepower of the engine, and the vehicle weight.
Later on, we'll do the MPH at the traps, and how changes in the car
weight figures into all of this. This should provide what we can expect
out of the TR, or any car for that matter. Hope it interests some of
you...
For E.T., you need to know the vehicle weight and its horsepower when
such a test is taken. My '73 car, with me in it, figured 2500 lb. when
weighed on public scales, which I consider 'close enough'.
The formula for E.T. involves the cube root of the weight-to-power ratio
multiplied by a constant of 5.825. (This will be different than the
power-to-weight ratio, needed for MPH, as we'll explore later on.)
E.T. = weight divided by hp. Find the cube root of this, and multiply it
by 5.825.
Stock Car Example: 2500 / 105 = 23.81 The cube root of 23.8 is 2.88.
Multiply this by the constant of 5.825 for an E.T. of ....
16.8 seconds!
Your HP and weight may be different. You can change the 2500(wt.) and
105(hp) to what you think your car is, and plug it in.
Later we'll use a slightly different formula to see what kind of H.P.
it takes to reach an E.T. of under 11 seconds in a 1/4 mile.
Dick Taylor
W/Auto Math Handbook
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