Glossary
turbocharger
A turbocharger uses the engine's exhaust to spin a turbine that drives a compressor, forcing more air into the cylinders so more fuel can be burned and more power made from the same engine.
A turbocharger uses the engine's own exhaust to force more air into the cylinders. The exhaust spins a turbine, that turbine turns a compressor mounted on the same shaft, and the compressor packs air into the intake. With more air in the cylinder, more fuel can be burned, so a small engine can make the power of a larger one.
It runs on energy that would otherwise leave through the exhaust, which is why a turbo adds power without much of a fuel penalty. Its drawback is lag: the exhaust has to build before the turbine can spin up, so the extra power arrives a moment after the pedal.
The air leaving the compressor is hot because compressing it raised its temperature, and hot air is less dense, so an intercooler sits in the path to cool it down again before it reaches the engine. A supercharger does a similar job but is driven mechanically by a belt, trading lag for a permanent drain on the engine.
Taught in
Related terms
- mass airflow sensor — A mass airflow sensor sits in the intake and measures how much air is on its way into the engine, so the computer can add the matching amount of fuel.
Source: Official ASVAB — subtest descriptions (what each subtest asks) and the CAT-ASVAB scored-question counts (accessed 2026-09)