[Th0r]

A Turbo is usually hooked up to a custom header, and the fumes of the exhaust that is exiting the heads will drive the turbo’s impeller. A supercharger is driven from the vehicles belt system, which is usually driven by the crank pulley.

There are 3 popular types of superchargers which all have different characteristics. 1. A centrifugal type supercharger. These compressors look like a turbo and have similar qualities. Since the belts drive the supercharger they usually are on all the time. A centrifugal supercharger will usually start building up boost in the lower RPM range and then you will see full boost at redline. A centrifugal supercharger builds boost per RPM speed. So lets say you have a 6psi system. You will start seeing 1psi around 2500 RPM and then 6psi at your redline.

The 2 other common types will be a Roots and a twin-screw type supercharger. These types offer great low end HP and torque since the boost curve comes on instantly. Unlike centrifugal type superchargers usually you see full boost in the lower RPM range and it stays linear throughout the whole RPM band. These are usually great for towing, road course racing, and even drag racing.

Now turbo systems use the exhaust fumes to drive the turbo, and usually you will have a slight turbo lag. Turbo lag is the time it takes the exhaust fumes to turn the turbo impeller. Once the impeller is spooled up usually you will reach full boost pretty quickly. Since the turbo is run off the exhaust the temperatures are normally very high and that’s why there will be a strong need for an intercooler and even a turbo timer. These items help control the heat so you do not ruin your turbo and engine.

Also another major difference is the way the boost is controlled. Since a supercharger is run off of the belt system, usually you have to change the pulley to get more boost out of it. One of the befits of this setup is that you do not have to worry about over boosting your engine, where if you do go to high in boost it will blow your engine. So usually the supercharger setup will be set at a conservative boost level, which is safe for your car. If you did want more boost all you have to do is get a smaller supercharger pulley or a larger crank pulley. This will spin the supercharger quicker giving you more boost.

Now with a turbo they have a wastegate and a boost controller that helps control the amount of boost you will get. All you have to do is turn the setting higher on the boost controller and you can change the boost pressure instantly. The convenience factor is there however the draw back is over boosting the engine and blowing it. On top of that there will be a potential risk of boost spike. Boost spike is where all of a sudden the boost pressure will go far beyond your normal setting and this can destroy your engine.

Now most supercharger systems are sold as complete kits so nothing is usually needed for it to work on your application. A lot of these kits are C.A.R.B. approved so you do not have to worry about being able to smog your car…this also means that it is legal for street use, so the cops cannot ticket you for it. Most kits will come with all the programming, fuel components, and all the belts brackets and hardware so you can bolt it on and go.

Turbo systems usually are very basic and you usually will have to add several upgrades in order for it to be safe and complete. Usually an intercooler, boost controller, turbo timer, and sometimes a wastegate is needed. On top of that you usually have to worry about the fuel components and tuning. These kits usually are not C.A.R.B. approved. A lot of streetcars will gain a more HP gains with a turbo system, however these systems usually have a custom tune in them. If you custom tune your supercharger system usually you will see equal amount of HP…or at least you will give them a run for your money.