So what's the noise difference and explanation between straight through, X-pipe and H-pipe? Anyone able to explain?
Cheers
C
For NA application;
Straight pipe - optimise exhaust sizing; when you thing about a pipe you bed to think about the size for both flow rate and velocity. Flow rate is the amount of a substance that can pass through the pipe and velocity is the speed that it needs to flow for the given flow rate. And so you can see for a fixed size of pipe the more flow (volume) you try to get down the pipe the higher the velocity.
This goes hand in hand with pressure. The higher the velocity the higher the pressure drop across that pipe. So the more flow you try and get down the pipe the higher the velocity and the more back pressure you create.
This leads onto the type of flows within the pipe ; lamina and turbulent. The ideal is lamina where flow is moving constantly and directly. This helps scavenge the next pulse of gas from behind it, creating a small vacuum into which it is pulled.
The problem with engines is flow, and therefore velocity is not fixed. This means that you can tune an exhaust but it won't be optimised for every point across the RPM range.
An X pipe (I don't fully understand this) is supposed to create a transition of all eight cylinder pulses and smooths the pulses. Now I. An see that if the firing order of the eight cylinders is balanced across the two banks this would be usefully it would fill the gaps.
H pipe is the same but rather than the gases adjoining they expand into the link pipe.
X pipes are better at top end power release whilst h pipe is better at low end power release.
Turbo charged engines work entirely differently.... Tbc