Exhaust
The exhaust system is designed to aid in the removal of burnt fuel and air from the engine. A sound limit is placed on the exhaust in competition.
we should also talk about header clocking by firing order into the collector - for scavenging goodness, we actually need way more on scavenging, this page is deserted
backpressure is a meme
Contents
Exhaust Form Factors
The exhaust form factor should drop out of your design constraints (e.g. packaging and weight) as well as your engine system model. There is no one right answer for the best exhaust system.
4-1
4-2-1
4-2
4-4
(never seen 4-4 but it'd be sweet. A drawback would be having to include 4 mufflers).
Silencers and Noise test
Muffler/Silencer
A muffler (or silencer) is an acoustical filter designed to ensure appropriate noise control in the exhaust system of an internal combustion engine.
Tuning
Runner Lengths
Just do a parametric study in WAVE or GT-Power to determine runner lengths. Because of the high temperatures and pressures involved, reduced order models such as Helmholtz (a linear acoustic model) start to break down. A key quality control during manufacturing should be maintaining equal runner lengths for each stage of the exhaust and minimizing flowpath disruptions due to weld beads or tube misalignment.
