Why A Cross Plane V8 Needs An H or X Exhaust Pipe
Crossplane V8 engines have a left and right bank each containing 4 cylinders. When the engine is running pistons are firing according to the engine firing order. If a bank has two consecutive piston firings it will create a high pressure area in the exhaust pipe, because two exhaust pulses are moving through it close in time. As the two pulses move in the exhaust pipe they should encounter either an X or H pipe. When they encounter the pipe, part of the pulse diverts into the X-H pipe which lowers the total pressure by a small amount. The reason for this decrease in pressure is that the liquid, air or exhaust gas will travel along a pipe and when it comes at a crossing the liquid/air/exhaust will take the path of least resistance and some will bleed off, thus lowering the pressure slightly. Without a X-H pipe the flow of exhaust would be jerky or inconsistent, and the engine would not run at its highest efficiency. The double exhaust pulse would cause part of the next exhaust pulse in that bank to not exit that cylinder completely and cause either a detonation (because of a high air-fuel ratio (AFR)), or a misfire due to a low AFR, depending on how much of the double pulse was left and what the mixture of that pulse was.
Read more about this topic: Exhaust Manifold
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“The point is to show who is the cross and who the crucified.”
—Max Frisch (1911–1991)
“We’ve got to figure these things a little bit different than most people. Y’know, there’s something about going out in a plane that beats any other way.... A guy that washes out at the controls of his own ship, well, he goes down doing the thing that he loved the best. It seems to me that that’s a very special way to die.”
—Dalton Trumbo (1905–1976)
“Only the really plain people know about love—the very fascinating ones try so hard to create an impression that they very soon exhaust their talents.”
—Katharine Hepburn (b. 1909)
“If you love music, hear it; go to operas, concerts and pay fiddlers to play to you; but I insist on your neither piping nor fiddling yourself. It puts a gentleman in a very frivolous, contemptible light.... Few things would mortify me more than to see you bearing a part in a concert, with a fiddle under your chin, or a pipe in your mouth.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)