Scrutinize runs
To get real accurate, you need to do what I call equalizing the ET’s based
on 60’ time differences. There are only 2 reasons why ETs change. 1- From horsepower
changes, and 2- from Traction changes. If the change was from horsepower, the
ET will progressively change throughout the run. ET changes from Traction will
be the same all the way down the track. To separate this you need to find the
run that had the best 60’ time and reference it for the rest of the runs. As
the weather goes up or down by 100', I figure the 60’ time should have changed
by .001 seconds on gas. The 60’ times will need about 200’ for a change of .001
seconds on Alcohol. So if you are comparing two runs on gas, where the one you
are comparing to the reference run has 200’ worse air, then you add .002 to
the reference run’s 60’ time that is what it should of been. I usually write
the 60’ time that it should have been above the real 60’ time, and put it in
parenthesis. Then subtract the difference. This difference needs to be subtracted
from the finish line ET so you are looking at the real ET’s without the influence
of run to run 60’ time variances. Write the corrected finish line ET above the
real ET and put it in parenthesis. If the 60’ times look reasonable in relation
to each other, just leave them the way they were. Next we should look for any
runs that were done at near the same Density Altitude and pick the one with
the lowest ET. That means the one with the quickest ET made the most out of
the available air. So scratch out the bad run. Likewise if you have two runs
that produced close ET's, but there was a couple hundred feet difference in
Density Altitude, the one that was done at the higher Density Altitude is the
better run because the one with the better air should of speeded up but it did
not. So scratch out the bad run. The rough rule of thumb for Gas is that you
should pick up a hundredth with every 100’ to 190’ of better air. The faster
the car, the more air it takes to make the ET change by .010 seconds. Alcohol
usually takes 225’ to 400’ for the ET to change by a hundredth. It takes a greater
change of air for the faster cars like a Super Comp car as opposed to a 12-second
Bracket car.