Forced induction is anything that adds pressure to the intake on your engine. The most common forms are superchargers and turbo chargers. Both of these do pretty much the same thing, but in different ways. A supercharger is a compressor driven by a drive belt connected to the crankshaft of the engine. A turbo charger is also a compressor that forces air into the engine, but instead of being belt-driven like a supercharger, it’s driven by the exhaust gases coming out of the engine. Both of these systems help increase the power output and efficiency of the engine.
Superchargers produce max output at lower RPMs, which makes getting off the line quicker. Turbochargers, on the other hand, have a delay in power delivery. They need to “spool up” before they start increasing the engine’s power. A problem with either of these systems can cause poor fuel economy. Since they create pressure in the intake, you need to employ different testing methods when diagnosing these systems. For instance, instead of spraying carburetor cleaner or water on the intake when looking for leaks, you might try a mix of soap and water. When the soapy water reaches a leak, it will start to bubble when the intake is under pressure during boost, indicating the leak’s location. Other problems, such as bearing failures or control issues, can hamper the ability of these systems to operate properly. When these systems fail, you will see a decrease in power and fuel economy. Consult your vehicle’s service manual for testing and evaluation of the system on your vehicle.