What is the difference between a supercharger and a turbocharger?
The main difference between a supercharger and a turbocharger is the way they make power. A turbocharger uses exhaust gas to turn its turbine, while a supercharger uses power from the engine (Through a pulley). While at first it seems like the turbocharger is more efficient at making power since it uses spent resources, they both have their advantages and disadvantages. Although the turbo is more efficient and does not “take power to make power”, the pressure it generates is harder to monitor since it relies on the constantly changing exhaust gas velocity, meaning that it always produces varying pressure. A supercharger, on the other hand, uses power from the engine to create even more power. While this seems inefficient due to its parasitic nature, the pressure it generates is more consistent and does not sacrifice driveability. Neither is better than one or the other, but rather are choices available for certain end-user needs or criteria.
First of all, there are a couple different types of superchargers (positive displacement and centrifugal). The most popular these days seems to be the centrifugal supercharger which is basically the same design compressor as a turbocharger compressor. These compressors both increase in airflow and efficiency with impeller RPM’s. (Which basically means that doubling the impeller RPM doesn’t double the airflow, it increases the air flow exponentially.) So in the case of the supercharger, where it is directly run from a belt and pulley attached to the crankshaft which ties impeller RPM in a direct ratio to crankshaft RPM, the boost increases linearly with engine RPM. Example: If you want to run maximum boost of 8 psi, you would gear the drive pulleys to produce 8 psi at maximum engine RPM. Lower RPM’s would produce less boost linearly. I.E. 8 psi @ 6000rpm, 5 psi @ 4500rpm, 3 psi @ 3000rpm, and 2 psi @ 2500rpm.) Thus, maximum boost is only attained at maximum engine RPM which only lasts f
