The exhaust manifold is bolted to the cylinder head or onto the exhaust ports.
On passenger vehicles the exhaust manifold is usually made of cast iron.
Sometimes there is a separate passage for each exhaust port.
The length of the passages in the exhaust manifold should be designed so that pulses of exhaust gases from one cylinder assist the flow of gases from another.
It has large tubular sections, to improve gas flow, And no sharp bends to slow the gases down.
As well, the exhaust manifold must be shaped to allow for the location of the engine, and the bodywork of the vehicle. Some vehicles use heat shields to protect nearby components and the passenger compartment from the heat radiated from the exhaust components.
