Ford Mustang Tuning Techniques - Tuning In

There's more to being competitive in a race class than simply bolting together a combination, throwing it in a chassis, and pointing the car down the track. Many, many hours must be spent tuning, tweaking, and testing the combination to get the most out of it. That's especially true in NMRA Factory Stock racing with its many limitations on the car's drivetrain and chassis combinations. Here, endless tuning can be of real benefit. Dyno testing and track testing are where the racers put their hours in, and Uncle Robin Lawrence and his Factory Stock red notch are no exception.

Robin "Boy Wonder" Lawrence-known among the Factory Stock ranks as "the dyno guy" because of his endless dyno testing-wanted to share with us some of his tuning techniques as well as the hardware he uses with his new engine combination ("Taking Stock," Sep. '02, p.157).

Dealing With PMSOne of the most interesting aspects of Robin's Factory Stock racer is his use of the Programmable Management System. While the PMS is an excellent product, it is usually found in blower or nitrous applications. When we asked Robin why he uses the PMS on a Factory Stock car (which is, of course, naturally aspirated), he told us that, over 4,000 rpm, the PMS functions as a stand-alone controller. This means that while the PMS is still using sensor data from the barometric pressure sensor, the throttle-position sensor, and the mass airflow meter, it is eliminating other EEC IV data, which makes the car more consistent from pass to pass or from dyno run to dyno run.

The PMS, though a full-featured tool with a handheld tuning interface, can also be used with a computer-based software program called Inter-ACQ (pronounced In-ter-ack). While Robin doesn't use the Inter-ACQ data-logging and tuning software, Rick Anderson does for his dyno work. Although the PMS allows you to make a change at a given rpm and then configures the curve for you, with the Inter-ACQ software and a laptop computer, changes can be made every 500 rpm for finer adjustments. The software also allows the PMS to go into stand-alone ode at 3,000 rpm instead of the 4,000 that is built into the handheld controller.

Robin has tried other devices, but he was constantly fighting with tuning changes. Back then, even trying to make a change as small as 2 percent in fuel tables was a struggle. Now that he has a PMS on board, he says there's no looking back. While Rick Anderson suggests a 4-percent change for the PMS to make a difference, Robin has successfully seen improvements using the PMS with fuel-table changes as small as 2 percent on the dyno.

Timing Makes PowerRobin's other ultratrick tuning aid is his new MSD Programmable Digital-7. While the PMS can control ignition timing, Robin prefers to use the Digital-7 on its own by locking the timing adjustment out of the factory distributor. He does this by removing the SPOUT plug to fix the base timing at a constant 10 degrees. This new ignition from MSD is fully programmable with three steps of adjustable retard function; programmable retard curves for launch, start, and gear changes; and plot timing curves via the run-curve option and launch-curve option. The Digital-7 also allows for individual timing changes per cylinder. A handheld control box can be used to program these functions, but Robin prefers to use the optional PC interface software from MSD for his tuning.