In naturally aspirated trim,...
In naturally aspirated trim, Aaron Macintosh's '93 Mustang GT produced 309 rwhp and 341 rwtq. Thanks to 10 psi of boost, our engine blasted the rollers at JPC Racing to a peak reading of 460 rwhp and 479 rwtq. It works out to a 155 rwhp and 138 rwtq gain from the Vortech H.O. kit.
The programmable 6AL-2 is the top of the line and incorporates three rev limiters, programmable timing curve for nitrous and boost applications, timing controls that are more accurate and controllable than the dial on MSD's other products, timing launch control to help get the car out of the gate, and of course, the benefits of the multiple spark discharges for better ignition power. Since it is a digital ignition system, the timing curves and rev limiters are adjusted and plotted on a computer program from MSD. The software is compatible with PC computers only.
Other products work effectively to remove timing based on a fixed curve using a dial, and the digital system allows us to get very specific in timing controls. For example, the dial is put to 1-degree ignition retard for every 1 psi of boost in other ignition systems. As boost rises, the timing is retarded to that pre-determined number. With the programmable 6AL-2, we can create our own curve. As Eric Holliday of JPC Racing stated during the installation, "The curve with this box is not fixed. We are starting with only a half degree of timing retard for 1 psi of boost. The low boost doesn't require as much timing to be removed as it will at 9 or 10 psi. It allows the car to be snappier in low boost."
Vortech adds a button over...
Vortech adds a button over the bolt that reads "Removal Voids Warranty." We were never good at following instructions and pried it off with a screwdriver to gain access to the pulley bolt.
Burcham chose to lock in the timing at 25 degrees total (10 degrees base with spout out) and rely solely on the MSD box for timing commands. He programmed the retard to start off lightly. As mentioned, at 1 psi of boost, timing is retarded only a half degree. As the boost goes up, so does the retard-at 3 psi our test vehicle's engine will have 1.5 degrees of timing removed. As manifold pressure rises, the retard gets more aggressive. At 5 psi, there is 5 degrees of timing negated. Burcham set the timing retard at 9 degrees at 8 psi and 12 degrees removed at 10 psi. He chose to remove more than 1 degree per 1 psi of boost at the higher levels because of the stock short-block in the test vehicle. A 2-bar map sensor is hooked up to the 6AL-2 so it can reference the manifold boost.
Last month we outlined the fuel system, which is a bit overkill for this application, but Burcham would rather have too much than too little. Initially we added a set of Ford Racing 60-pound injectors (with a Pro-M 80mm MAF sensor matched to the injectors), a Vortech T-Rex in-line fuel pump, and a UPR 255-lph in-tank pump. Burcham kept the engine running smoothly and cleanly thanks to a DiabloSport chip-it allows the engine to idle nicely and not overrun with fuel.
The MSD box comes with wires...
The MSD box comes with wires that are specific for each aspect of the unit's capabilities. The 6AL-2 will interface with the ignition system, rpm readings, and a MAP sensor.
This month, Burcham adds a new product that is set to hit the market shortly. It is an MSD Programmable Fuel Pump Boost Control that utilizes a PC-interface to build a custom curve to increase fuel pump output (through voltage increase), much like the programmable 6AL-2 does for spark.
Overkill? Definitely, but we felt the product was too neat to pass up, so Holliday wired it into the car. Both the UPR and Vortech fuel pumps are wired into the box, so they react the same to the adjustable curve. A vacuum line is run to the fuel pump-control box so it can read boost output and adjust the voltage.
Adding the fuel pump booster is an easy way to supply more fuel to the engine without buying new fuel pump(s) or even adjusting the computer tune in the ECU. The box will add a minimum of 1.5 volts at 1 psi, and it can go as high as 22 volts at 15 psi. In stock trim, the fuel pumps operate at 13.7 volts at idle with a functioning alternator. The MSD software is simple too. You don't need a background in programming to make adjustments. It is a basic graph that plots boost pressure and voltage output.
The main graph is easy to...
The main graph is easy to read and operate. Our timing retards for boost is shown in the lower right corner. Along the top axis is the manifold pressure, and the axis on the right is the amount of timing removed. As you can see, the curve prescribed by Burcham starts off slowly and the timing removal gets more aggressive as boost increases. The graph on the top is turned off and is a timing retard based on engine rpm. The rpm/retard graph is useful for traction-limited applications. A user can leave the starting line with timing removed so the tires hook to the surface. As the engine climbs higher, the timing retard backs off and full timing can be had at a predetermined rpm level.
The Data Editor screen allows...
The Data Editor screen allows the user to adjust engine rpm limiter, launch rpm limiter, and burnout rpm limiter. The other parameters in the box are also accessed through the Data Editor window. The Rev Limiter screen is open here, and Burcham has it set at 6,200 rpm. This rev-limiter will not override the ECU rev-limiter; Burcham set it lower than the ECU's factory setting of 6,250 rpm. This was done because the MSD box cuts spark to limit the rpm while the factory limiter cuts fuel, which is a bad thing in an application like this one.
The mainstay of MSD 6-series...
The mainstay of MSD 6-series ignition boxes is their ability to keep multiple charges rushing through the ignition system. Here the box plugs directly into the coil to provide the extra punch, a welcome addition to a supercharged engine.