G. TRANSMISSION SHIFT POINT MPH & RPM
(AUTOMATICS ONLY)
Be sure to read and understand this entire section before
attempting to re-program your shift points.
The shift point option allows you to change the RPM at which
your transmission shifts at wide-open throttle to find the very best
shift points for maximum acceleration. You can try optimizing the
shift points using the seat-of-your-pants technique, but how will
you know if your e.t.’s improved or not? The only accurate
method for this optimization is at the track with timing slips as
the measuring device.
In order to optimize the performance of any vehicle, consis-
tent test results are necessary. If a vehicle varies plus or minus
1/10th of a second in the quarter, run to run, with no changes, it is
impossible to test any product (shift point, starting line RPM, etc.)
that has the potential to gain 1/10th or 2/10ths of a second,
because the gains or losses on any one (1) run could be due to
inconsistency rather than the variable being tested. Therefore,
before testing anything, make the vehicle consistent.
Wheel-spin, if present, is the overwhelming cause of incon-
sistency. You must develop a starting line technique that gives
you the best repeatable elapsed times. Tires are the most impor-
tant product you need to cure wheel-spin. For street driven
vehicles, we recommend D.O.T. approved street slicks as large as
you can fit under the wheel wells of your vehicle. In any case,
before testing shift points, arrive at the starting line technique that
gives you the best repeatable results, with or without slicks.
Throw out any run with excessive wheel-spin, and try to get at
least three (3) runs that are within 4 or 5 hundredths of a second.
Then average them and use this average value (not just your
best run) for all testing comparisons. Your best e.t.’s will occur
when you leave as hard as you can without wheel-spin. Confirm
this by practicing and observing the results.
And finally, a very important point for any and all high-
performance testing...always test only one (1) variable at a
time until it is optimized. For shift point optimization, this
means test only one (1) shift point at a time until the best RPM is
found, leaving all other shift points alone. Once the best 1-2 shift
point is found, program it in and leave it. Then repeat the same
optimization procedure for the 2-3 shift point.
It is not usually necessary to optimize the 3-4 shift point
(unless the gearing in the vehicle causes the shift to occur during
the 1/4-mile run) because it will occur at a speed so high that it is
out of range, even on a race track. However, if gearing is causing
either the 2-3 or the 3-4 shift to occur just before the end of the
1/4, you should try raising the shift point enough to allow the
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