We upgraded our base Vortech SCi-trim blower kit to H.O. specs and also added a fancy prog
Last month we modified a '93 Mustang GT with a basic supercharger kit from Vortech. The entry-level blower added 6 psi of boost to our test subject, and the result was 96 rwhp. It is a bare-bones system that includes nothing more than a new self-lubricating Vortech V3 SCi-trim blower kit. JPC Racing handled the installation and proprietor Justin Burcham tuned it with a custom chip. After seeing how easy it was to add nearly 100 rwhp, we wanted more.
The car pounded out 405 rwhp, up from the baseline of 309. The test vehicle runs a stock short-block with Trick Flow heads, Edelbrock intake, and a mild camshaft. Adding more with a supercharger seems easy enough-just spin the blower harder, right? To do so, we upgraded our base kit to the High Output (H.O.) version from Vortech, but along with it came some extra baggage.
In most cases, adding more boost is easy. A smaller blower pulley size will spin the centrifugal blower's impeller faster. "Changing the blower pulley is the easiest way to add more boost. But when doing that with the base kit, you need to address some issues," comments Ricky Best of Vortech Superchargers. Just adding more boost comes with consequences, and the company's H.O. upgrade addresses those very issues.
Upping the boost from 6 to 10 psi requires an ignition timing retard system, bypass valve,
Burcham also wanted to employ some other goodies, too. On the Vortech side, the two major components in the H.O. kit are an eight-rib blower pulley setup and a bypass valve. Vortech also includes a T-Rex fuel pump (which we added last issue due to the modified engine package), different FMU setting to adjust fuel, and an MSD/Vortech timing retard box (when you're under boost).
The Vortech parts work great, but Burcham elected to leave some components in the box. First was the FMU-he discarded it since this engine has Ford Racing 60-psi injectors, a healthy fuel-pump arrangement, and custom tuning. The ECU is modified with a chip from DiabloSport. Burcham made adjustments to keep the air/fuel ratios steady. The MSD/Vortech timing retard box was also left on the shelf as Burcham turned to the MSD Digital Programmable 6AL-2 to control timing under boost and enhance the spark output, among other things. The JPC mastermind also likes the 6AL-2 because of its rev-limiter capabilities. This MSD box keeps things simple, and enthusiasts don't have to mount multiple ignition controls and rev-limiter devices.
Macintosh's Mustang features a stock short-block with Trick Flow Twisted Wedge heads, Edel
The timing retard is required to prevent detonation due to increased cylinder pressures. Our mild 6 psi of boost only required a little timing removed. Thanks to our vision of 9-10 psi, our engine needed more timing removed. We couldn't just dial back the timing manually in the ECU like in the 6-psi application because it would compromise driveability. The best way to do it is remove timing little by little as boost increases, and the only way to achieve this is to add a timing control box.
"I like the programmable 6AL-2 because it has everything in one box. That makes it easier to mount, and MSD has great programmable features that can be adjusted on a laptop," comments Burcham. "Adding an MSD 6-series box of any kind is always a great idea with a supercharger. The multiple sparks help the combustion process."
MSD sells several versions and the Digital Programmable 6AL-2 is its latest. The base model 6A enhances the ignition output with multiple discharges. MSD adds L to the name for the rev-limiter option and the product is the widely known as the 6AL box. Moving down the list is the 6-BTM, which is essentially a 6A box with provisions to retard timing per psi of boost along a fixed curve.