Stroke 4: Blow. Fourth in a Four-Part Series
After the Big Bang of combustion when we made [most of] our coveted horsepower, we have to eliminate the waste – blow the by-products of the explosion out of the engine. It’s really just housekeeping – the cleanup phase, right? A throw away stroke in the four-stroke internal combustion engine? Au contraire mon frère! The exhaust stroke is important to us petrol heads for at least a couple of reasons. One is a technical reason and one is a spiritual reason.
First, there is still horsepower to be made. Voiding the combustion chamber of by-products in teh correct way will reduce the parasitic drag on horsepower being generated in other cylinders while the exhaust valve is open. Design of exhaust systems takes into account pressures all the way through the system to assure there are no conflicts with the other three strokes occurring elsewhere in our precious engines.
Second – the right exhaust sound tickles a certain part of our brains. The pleasure center, so to speak. Where other fun things are recognized and appropriately responded to. But we’re talking about engines here. Suffice it to say that the visual and auditory aspects of exhaust components are no to be overlooked!
Check out these beauties. Without much difficulty, the QCrew can imagine the sounds that these works of art make when in full song!