Oldsmobile/Buick: Supercharge and Turbo, drag racing cars, roots blowers

Question
Dear,
What is (are) the difference(s) between "Supercharge" and "Turbo" that I have seen on some cars? Please help.
Thanks,
Sy Huynh,

Answer
Hello Sy,
For the most part turochargers and superchargers simply add more horsepower to an engine. However, they are radically different in obtaining the results. Supercharged automobile engines have been around since the 1930's. There are two types of superchargers. One called a roots blower and a centrifugal ball or vane drive. The roots blowers, commonly known as GMC's made by general motors, were used on diesel semi tractor trailers to add power. They were adapted to gas engines and used on race cars. These are the large units (usually chrome) you see on drag racing cars. They can utilized either fuel injection or carburation. Roots blowers have gears that resemble rolling pins, they spool up the in coming air and force it into the engine, more air and fuel means more horsepower. Centrifugal superchargers accomplish the same in theory but are more compact. Paxton, Vortech, are some of the more popular kits availiable. A turbocharger uses the exhaust gases and then recirculates them back through the motor. Turbocharging is quite popular and has its pros and cons. First, it is more efficient at creating horsepower and the boost can be adjusted. The cons are the power is a little slow coming on. This is called "turbo lag" With supercharging the power is there when you hit the gas, with no lag. Supercharging pros and cons is the amount of air in coming can equal anywhere in the neighborhood of 6 to 18lbs of forced air. This greatly increases the compression ratio of an engine. An average street car with a 8:0.1 compression would raise to about 11:5.1 with a supercharger providing about 7lbs. of boost. With todays gasoline being of such low octane the engine would detonate, without retarding the ignition timing or using octane booster. Turbocharging luckly dosen't have to worry about such high levels of octane, but will not produce the horsepower of a supercharger. On average a supercharger will give you about a 40-60% increase. For instance a 5.0 mustang gt stock puts out 225hp, with a supercharger it would increase to about 360hp. Turbo's are quite popular. The most sucessful ever was the Buick Grand Nationals. A 3.8 V6 capable of 300hp. These cars were screamers. Turbos have been put on most cars like the dodge daytonas, and others going back as far as the late 1970's. Turochargers on 4cyl. cars are really a waste of time, especially when you consider any v6 or v8 can accomplish the same horsepower of a turbo 4 without using one. Great question! My 1989 mustang gt has a Paxton centrifugal supercharger. The boost output is small, only 6lbs. The motor is completely stock and so is the rest of the car. The horsepower is near 345. You can definitley feel the pulling off the line and down the track! I do have a slight detonation problem and have to constantly use premium fuel. Most turbo and supercharger kits are availiable for a variety of cars not equipped. Installation is not difficult, but the kits can be expensive, starting at around $2,400 for a Paxton kit for the 5.0 mustang. One of the top turboharger kits are made by Banks turbochargers. Though there are many new companies manufacturing. Thanks for allowing me to answer. Hope I've helped out some! Ray