Your intake manifold. It takes in air and sends it to your engine's combustion chamber. This is basically the start of the combustion process. After all, you can't have combustion without air.

How To Tune Intakes For More Horsepower Intake manifold tuning is critical for ensuring optimum horsepower across a wide rev range. Longer, narrower intake runners lend themselves well to low RPM ...

I think it's safe to say most of us, even those of us uncomfortably car-obsessed, don't spend a lot of time thinking about intake manifolds. I feel like we tend to treat them as just those tubes that ...