1999 Ford SVT Lightning Blower Upgrade - Wretched Excess

Whipple shed some light on the internal workings of twin-screw blowers. "The supercharger is driven off the engine's crankshaft, via a belt," he says. "As the rotors rotate (which turn opposite each other), they go by the inlet ports, which helps create a suction phase, allowing air to fill the flutes of the rotors. The air is moved axially through the casing. As the rotors continue to rotate, space gets progressively reduced, thus it compresses the air charge until it reaches the discharge port, which has a predetermined pressure ratio. From there, it's forced out of the discharge port. Because it's exited at a higher pressure ratio, the air enters pressurized areas with far greater efficiency due to far less leakage." Twin-screw blowers have gained popularity over the past five years thanks to the aftermarket blowers for the Terminator Cobra and Gen 2 Lightnings. The twin-screw combo is highly efficient, and the results speak for themselves with 9- and 10-second Cobras and Lightnings at tracks across the country.

Installation was handled by JDM Engineering, and it went smoothly as the 3.4L unit is a direct bolt-on item. We encountered a few hiccups here and there, namely the hard intercooler hoses and the IAC (Idle Air Control) motor. "The hard intercooler hoses that run down the passenger side of the supercharger are no longer a direct fit, so we had to bend the mounting brackets on the lines and run two new coolant hoses to the back of the blower to make it work," says JDM's Jim D'Amore. "We like this option better than the alternative of just using rubber lines. The hard lines look much cleaner."

The IAC motor's location interferes with the coil packs, a problem that most people have with the 3.4L blowers, according to many message-board conversations. D'Amore had his machine-shop guys take down the IAC mounting location. This procedure was practically effortless and provided ample clearance between the IAC and coil packs. Other than those two issues, the installation was trouble-free and simple. We had visions of stupid horsepower, but we were thrust back to reality after only a couple of dyno pulls.

The first problem we encountered on the dyno was in the boost department. As D'Amore fed into the throttle and pushed the blade wide open, the 5.4 screamed, and we saw 31 psi of boost in the lower-rpm zone. The massive boost pushed off a few vacuum lines, causing the engine to run rough, and he quickly jumped off the loud pedal. Nevertheless, the engine was up about 80 hp from previous tests. This was promising. The blower pulleys selected for this application were in left field thanks to the massive blower sitting on top of our modular engine. Our truck features a 10-inch crank pulley (also known as an 8-pound pulley), which is combined with a 3.5-inch blower pulley. The pulley combo provided too much blower speed. Fridge was sporting a 3-inch upper and the same crank pulley when it was rolling with the 2.3L huffing 21 psi of boost. Even with a larger blower pulley, the 3.4 unit unleashed 10 more pounds of boost. D'Amore made the executive decision to keep the 3.5 upper pulley and put on an 8.75-inch crank pulley (4-pound lower). The new combo brought boost down to a more reasonable 24 psi. and Fridge rolled out 710 hp at the wheels. But this brought us to problem number two-a tapped-out fuel system.