Performance DIY by DIY Guru

Backpressure : The myth and why it's wrong. I. Introduction One of the most misunderstood concepts in exhaust theory is backpressure . People love to talk about backpressure on message boards with no real understanding of what it is and what it's consequences are. I'm sure many of you have heard or read the phrase "Engines need backpressure " when discussing exhaust upgrades. That phrase is in fact completely inaccurate and a wholly misguided notion. II. Some basic exhaust theory Your exhaust system is designed to evacuate gases from the combustion chamber quickly and efficently. Exhaust gases are not produced in a smooth stream; exhaust gases originate in pulses. A 4 cylinder motor will have 4 distinct pulses per complete engine cycle, a 6 cylinder has 6 pules and so on. The more pulses that are produced, the more continuous the exhaust flow. Backpressure can be loosely defined as the resistance to positive flow - in this case, the resistance ...