what advantage does dual exhaust have over single exhaust?



what advantage does dual exhaust have over single exhaust?

In: Engineering

More exhaust pipes means more airflow. More airflow means you can burn more fuel fully which means more combustion and more power.

There is no advantage afaik, only disadvantages for actual dual exhaust.

Given backpressure between tailpipes which are split on a V8 engine (left and right manifolds) doesn’t do much. Each handles 4 exhaust valves which are on each side of the engine. If you look at the firing order for a V8 you will see it’s not symmetric, so sometimes the left and the right pipes would fire causing different exhaust pressure rates as cylinders fire.

On a properly tuned single or cross pipe exhaust (fake 2 barrel exhaust with a pipe between them) the pressure going out the tailpipe(s) create kind of a constant vacuum which helps pull exhaust out of the combustion chamber when the exhaust valve opens. When it closes, there is a slight additional vacuum in the cylinder, so when the exhaust valve closes and the intake valve opens, it’s already sucking fresh air in before the piston starts goes down to pull in fresh air causing a very slight effect similar to a turbocharger putting more O2 in faster.

It creates more horsepower and torque simply by leveraging the existing airflow that’s already leaving that causes a vacuum via the exhaust valves.

There are a square-billion different exhaust and engine combos. That’s what dynos are for. Install and test. Compare to the others. Repeat and select based on what you are doing. (Quick line, top speed, acceleration, etc) there are tradeoffs for everything.

Don’t get me started on a ELI40 on fluid dynamics and pre-ignition.

Another reason for dual pipe over single pipe is that dual pipes for the same flow rate are flatter under the car than a single big pipe. It helps with clearance and packaging the exhaust cleanly under the car.