| manifold, not the pulses or the flow. Consider this: Single turbo supras have one throttlebody that feeds all 6 cylinders through the intake manifold. When the boost gauge reads 20psi, would you say that all 6 cylinders are seeing 20psi at their intake valves? This is an obvious answer, no doubt, but it is analogous to what happens in the exhaust manifold. As RPM increases and airflow through the engine increases (lets consider at WOT), the entire exhaust system is going to flow that air out with an increasing amount of pressure within the exhaust manifold. This is mostly due to the fact that you are trying to move more air through the same exhaust components. Pressure will increase in the exhaust manifold as RPM increases with the engine under load. But the increase in pressure within the exhaust manifold has very little effect on the resistance of flow produced by the manifold; that is a function of the manifold's design. I think I may have gotten what you were talking about before though, although you haven't made it entirely clear as to what you are referring to. As the pressure within the manifold increases, this will increase the amount of latent pressure within the cylinders at the end of the exhaust stroke. If this latent pressure within the cylinder is higher than the intake manifold pressure, you will experience reversion, as you mentioned earlier. In addition to this though, the flowrate of the exhaust manifold still plays just as much a role at higher exhaust manifold pressures as it does at lower pressures due to the fact that gases are still having to flow through the manifold itself.
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Are you an enthusiast? If you are out to describe the truth, leave elegance to the tailor.
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16:49:46 02/15/07
