Supercharged Mopar Engine - 875hp Procharger 440

For exhaust header gaskets, we again went to Flatout, this time for metal-cored graphite units. The quality and fit were impressive, and they sealed beautifully. Those guys make nice stuff.

Installing the blower unit and ducting was accomplished with the engine mounted to the Westech dyno. We chose an F1-R race blower, for the ability to provide high boost in a 440-cubic-inch engine, though The Supercharger Store offers other blower units tailored for more moderate boost.

A vacuum-referenced blow off valve is required to bypass boost at low throttle opening. With the race unit we used, the bypass tube and flange must be installed in the pressure pipe. These pieces came with our kit.

To aid in running high boost and power output on pump premium, the optional water/methanol injection system from The Supercharger Store was mounted to the inlet side of the compressor. The comprehensive system comes with a pressure switch, an anti-siphon valve, a pump, the tank, and all of the required hoses and fittings.

For high output blown applications, the exhaust system must be designed for a high flow volume. We used TTI 2-2 1/8-inch stepped headers.

In high boost carbureted applications, one of the toughest jobs will be the ability to supply enough fuel, in the correct proportion, over a broad rpm range. We had the most success with a Race Demon RS carb, with the 1,050-cfm venturii, and annular boosters. Really, for street use and high boost, electronic fuel injection is probably the most accurate approach.

We found the Extreme Velocity air hat provided a benefit in fuel metering, with its taller, larger-radius design improving the air approach into the carburetor.

A hardy fuel system with a boost-referenced bypass regulator is a must for blown applications. Monitor and dial in the fuel pressure to ensure it is sufficient at all rpm and boost levels, or the carb will simply run dry.

Frustrated by the serpentine belt, we swapped the drive pulleys to a cogged-belt drive from The Supercharger Store, which is actually the arrangement specified with this blower (see text). With a cogged belt, slippage is eliminated, and less belt tension can be used, which has to be easier on parts. This setup looks the way a real blower drive should.

The cogged drive eliminated all of our slippage problems and allowed to blower to make much more boost. We found it far superior to a serpentine.

Initial tests running with the 12-rib serpentine belt drive showed slippage, as evidenced by the rubber residue on the brackets, and ended with eventual belt failure.

So, what was it all worth? What began as a bread-and-butter 446 made 421 hp as tested without the blower. Under boost, it became a monster, making a peak of 878 hp and 745 lb-ft of torque. The power was consistent run after run. Blowers work!

When activated by a boost-referenced switch, the water injection nozzle sprays a fine mist of cooling water directly into the compressor inlet. The effect is charge cooling. A cooler charge makes more power, and reduces the tendency to detonate, while detonation suppression is further augmented by the introduction of water to the combustion process.

The water injection kit is complete with a fuel cell to hold the fluid, a high-pressure pump, the pressure switch, a check valve, and all of the tubing nicely supplied with quick-disconnect fittings. It's all there, and we had it quickly rigged for dyno duty. Various blends of water and methanol can be substituted for straight water. An easy way to get an appropriate blend of methanol/water is to use windshield washer fluid, as recommended by The Supercharger Store. Formulations vary in percentages and for winter/summer grades. Check the product data sheet or label for the contents, or get a recommendation on brands from The Supercharger Store.