List---In the last post on this subject it was shown how to get the
Elapsed Time in a quarter mile, (on paper) when you knew the horse power
of the 6 engine and the weight of your TR. It turns ot that the E.T.
would be very close to 16.8 seconds, for a stock engined TR6.
The fomula comes from the Auto Math Handbook, which goes on to say that
it does not take into account such variables as driver competance,
gearing, and the vehicle's coefficient of drag. (We've seen how
sleek-bodied TR's, set up for racing only, look like.) Stock bodied
TR's, the kind that Road &Track did their road tests on, came in with a
slightly higher ET's of 17+ seconds. Even these varied from model to
model.
No matter, the formula given is for comparative testing, and will be
reasonably accurate, when carried out accordingly.
This time we'll look at what MPH one can expect when going thru the
traps at the end of the quarter mile. Using the same HP and vehicle
weight as before, an ET of 16.8 seconds should carry with it a trap
speed of 81MPH.
For those who would like to know this was figured, it is written like
this.
Fnd the cube root of the horse power divided by weight, and multiply
this number by the constant of 234. Thusly:
105 / 2500 = .042 The cubed root of .042 is .03476 x 234 = 81 (MPH)
Much easier when using those handy- dandy scientific pocket sized
calculators that have the 3v---- function key.
The 81mph is probably higher than most stock TR6 engines can push the
stock bodied car thru a quarter mile. Again, R&T report speeds closer to
78mph. Some reports include test weights of around 2680 lb., driver and
test equipment included. Using a weight of 2680 lb, the formula brings
the speed in at 79mph.
Later on, we'll look what the ET's and trap speeds of modified TR's, and
what such cars should produce, including the TR5 with it's 150hp.
Dick
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