The catalytic converter converts pollutants in exhaust gas into less pollutant substances like carbon dioxide and water.

An inline cylinder configuration places the cylinders in a single row either completely vertical or slanted. Due to this arrangement, an inline cylinder configuration makes the engine longer and, although it works well in four cylinder engines, performace suffers in larger engines due to the difficulty in evenly distributing the air-fuel mixture over the length of the engine.

The cast iron exhaust manifolds collect engine exhaust gas from multiple cylinder exhaust valves and deliver it to the exhaust pipe. Exhaust manifolds can be generic or specially tuned (header pipes) to the engine. Header pipes deliver higher performance but are more expensive and less durable.

The master (brake) cylinder converts pressure on the brake pedal to hydraulic pressure in the brake lines.

The electric fuel pump feeds pressurized fuel through a fuel filter to the fuel injectors via the fuel rail manifold. The fuel rail contains the fuel pressure regulator which ensures that the fuel injectors receive fuel at a consistent and known rate. Excess fuel bled off by the pressure regulator returns to the fuel tank through the fuel return line.