The image on the right is a typical exhaust layout that you would find on a car equipped with a four cylinder engine. Exhaust is collected from the cylinder head by the exhaust manifold. It diverts gases from each cylinder into a single pipe. Exhaust gases travel through a catalytic converter where harmful components such as Carbon Monoxide and Nitrogen Oxide are converted to inert gases.
The gases then pass through a muffler, which decreases the noise of the exhaust before exiting through the tailpipe. The tailpipe is normally located at the rear of the vehicle where exhaust gases have little or no chance of entering the passenger compartment.
A transverse V6 engine layout is where the engine’s cylinders are lined up from left to right inside the engine bay.
Transverse engine layouts are most commonly used on front wheel drive vehicles.
A longitudinal V8 engine has the engine’s cylinders lined up from the front to the back. This type of layout usually has 3 catalytic converters: one located on each side of the engine right after the exhaust manifolds, and the third positioned after the flex pipe. Converters with this layout are often very expensive to replace, as the assembly often contains all three catalytic converters.
An exhaust system that causes little flow resistance will free up more power and be more efficient.
A longitudinal engine like the one shown here is much more complex, and may have three separate catalytic converters.