Traction Through Timing
By Todd Ryden
Photos courtesy of Michael Ray, MSD, Dedenbear,
BANNED IN GLENDORA - PN 7531
latest Programmable Ignition, the PN7531, has
been banned by the NHRA. In January DRO's Agent
1320 mentioned the NHRA's ruling, with their reasons
of cost and the close competitiveness of the classes.
DRO got a couple of reader letters asking about
this specific product and decided to address the
larger subject of affecting traction through timing
The 7531 has a programmable slew rev limit.
This is a feature that lets a racer program
an rpm ramp over time. For example, if you launch
at 4,000 rpm and shift at 8600, you can ramp
the rpm over time from 4,000 to 8,600 rpm. This
function simply allows you to program how rapidly
your engine can gain rpm on the launch and after
a gear shift.
The important thing to note here is that none
of this occurs automatically. It has to be programmed
by the user, which comes down to knowing how
your car reacts and being able to read track
conditions, just like a good tuner knows how
to set the clutch or 4-link. Stay tuned to DRO
for more info on what other decisions are made
regarding this new ignition.
Now, here are some other products and timing
information for your consideration. -Editor
2002 NMCA EZ Street Champ, Bob Curran, uses
MSD's Programmable Ignition Control so he can
use a separate ignition curve to get his '96
Corvette out of the hole.
Once the car is rolling and Bob shifts gears,
the ignition automatically switches to a "run"
timing curve. (Photo by Michael Ray)
is a time and place to enjoy ripping off a big
smoky burnout and pretending you're John Force.
Off the line during eliminations is not the
The last thing you want to do after lighting the ambers is dump the clutch and watch the tach rocket into the red as the shift light screams and you feel the rear of the car waft around turning rubber into smoke. Adding insult to injury, you get to watch the win light click on in the other lane.
There is, of course, a good side to this - your engine is making killer power!
Now to harness that power to the tarmac.