Turbo charging vs. Supercharging

[Induction Concepts]

A comparison between a roots or twin-screw type (Whipple, Kenne Bell, Magnacharger, etc.) supercharger and a turbo version will be very similar in their power and torque curves. They will both make nice torque down low. This type of supercharger will probably make torque just a little bit earlier than the turbo version, but honestly, boost below 2500-3000rpms is not really needed on the street anyway. 2500-3000rpms is about the perfect rpm point for torque to come in.

The main difference will be that these types of superchargers are limited in the maximum amount of power they can make, usually in the 600hp range. We normally deal with the 600-2000hp range, so where they quit, we're just getting started.

That and the fact that all superchargers have parasitic losses, this can range from 75hp to 350+hp depending on how big the supercharger is. What this means is that whether you are in boost or not, you are always burning the gas to turn the supercharger, then, on the other side is the fact that if it wasn't for that parasitic loss, that would be an extra 75 or whatever hp that you could be putting to the ground instead of wasted spinning the supercharger. For instance, on a turbo system that makes 500hp, you will get say 400hp at the tires. On a supercharger system that makes 500hp, you would only put 325 to the tires.

With turbos, you don't have any parasitic losses, so it doesn't cost power to make power, which means better gas mileage as you only burn more gas when you have your foot in it, otherwise it will get the same mileage as stock. Also, all the power the turbos make will go to the tires, none wasted on parasitic losses. There is less strain on the engine with turbos because there is not parasitic losses.

Something else to think about is that superchargers create extra strain on the crankshaft from belt tension. The crankshaft isn't designed for all this extra lateral force from a supercharger belt. Normal accessories (A/C, alternator, power steering, etc.) don't require maximum tension. Supercharger belts have to be very tight to keep from slipping and tossing them off. It also causes pre-mature wear on the front main bearing for this same reason (side loadig the crankshaft snout).

But superchargers are relatively inexpensive and less complex. If you are looking for only a 500hp (or less) solution, then its probably the way to go. If you want more power than that, then turbos are the answer.

Centrifugal superchargers (Paxton, Vortech, ATI/Procharger, etc.) are another animal completely. They don't make maximum power until redline as they are rpm driven, so you have to really push the motor to make power, which is much harder on the engine. They don't make much power down low at all. I wouldn't recommend this type for a street car, a roots or twin-screw is a better choice.

If there was a better way to make power than with turbos, that's what I'd be doing.

Hope this helps.