From The Oakland Press

How will adding supercharger affect gas type?

Last Updated: 6/5/2012 12:56:57 PM

By Les Jackson

Q: If I add a supercharger to my engine, how will it affect the type of gas I need to use? I have a Dodge that’s a few years old and can get a supercharger to fit it from a friend who needs the money. What will this do in the way of increasing power and how does it change the fuel requirement? — Hank in Salinas, Calif.

A: A supercharger pumps high-pressure air into the cylinders, effectively adding more oxygen to the combustion process. This enables more efficient heat transfer and thus creates more power. Since higher air pressure is present in the combustion chamber, the engine’s compression ratio is effectively higher, which means you’ll need premium fuel to prevent pre-ignition due to heat of compression. In short, premium fuel is going to be necessary for smooth engine operation. Power increases of 25% or higher can be expected from superchargers, depending on boost pressures. Don’t overdo it, however, as crankshafts and connecting rods need to be strengthened for high boost pressures.