[Blue Thunder]

Supercharging is very stable, the crank shaft drives the S/C pulley at a given rate dependant on size. You will start making "X" lb.s of boost at a given R.P.M. (lets say 1600 R.P.M.) and a maximum boost at red line. No more no less! As long as the crankshaft speed goes up so does the H.P. and Torque. The H.P. power feel is very predictable and linear. In simple terms No Turbo lag, no over boosting, just nice even power increase like your Mini "S". Car manufactures like that scenario, it give a nice improvement in power to satisfy all types of consumers, the system even works well with automatics. The down side to Superchargers is they use a fair amount of the engines power to simply drive the blower, Actually there are a lot of items on the engine that do this, The water pump, alternator, a/c compressor, even the oil pump. But nothing draws power like a supercharger at full of boost. The hope is that we make more H.P. than we loose. And in most cases we do make more power.

A turbo, uses none of the engines power, other than the restriction that is created as the exhaust is forced to turn the exhaust turbine. So for the most part the H.P. lost to the S/C is available to turn the tires rather the S/C. The down side is to turn the turbine we need to build up exhaust pressure, and also additional time to pressurize the intake side. This wind up is the turbo lag. Smaller turbos spin quicker, but produce less top end boost (they run out of wind) Bigger turbos make more top end power but need more time to wind up. (Turbo lag) Turbine design also plays a big roll in all of this.When a turbo starts making boost it continues to increase as long as you supply exhaust pressure. The system then bleeds off some of the exhaust, bypassing the turbine, to reduce turbine speed. This happens via the waste gate.

For low and mid range R.P.M. operation supercharges work better, But If you spend you life above 3000 R.P.M. the turbo is a better choice.

We have just installed the smaller S/C pulley, and this mod in conjunction with the engine mods we had already done to the car, have really made a major improvement. The torque has increased overall by more than 30 ft. lbs.Horse power is up from, 144.1 H.P. at the wheels to over 186.0 H.P. The car is absolutely a rocket, ( a mini Rocket). Torque jumped by 20 ft. lbs. with the pulley alone, and the increase in power comes on sooner, with torque improving almost instantly when the car goes to boost. Torque steer is defiantly a problem so you don't want to do this without having both hands on the steering wheel. Using out base line performance gains in comparison to the factory published H.P. we calculate a 14% power loss to the wheels. Add 14% to the wheel H.P. of 186.0 and you get approx. 212H.P. With a little software change form our previous settings we expect to get even a few more ponies.

Al Hafner