| of sound and the speed of sound is mostly influenced by the temperature of the gases. The speed of the gases would be considerably more difficult to calculate as this is never a steady state condition in real-world operation. Since only one runner has gases flowing through it at a time, the speed of the gases through the manifold are more/less accelerating from a dead stop up to a peak velocity and then decellerating back to zero. The velocity is also different at differing points within the manifold - this peak velocity of gas motion occuring within the pulse wave created by the exhaust stroke. However, for sake of simplicity, we can assume a steady state condition by thinking of the flow through the manifold as being essentially the average of the gas velocity (minus a little bit). The real world phenomena that occurs within the manifold is considerably more complex but with the empirical data we have from previous flowtesting of manifolds, namely the comparison of flow results of an aftermarket manifold vs. a stock manifold and the respective power gains associated with upgrading, it is clear that a steady-state flow test is indicative (logically) of what kind of performance to expect. The whole approach of looking at the pulse wave timing really goes out the window, especially in a turbocharged setup where the turbine acts as a buffer to the pulses.
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[ agpowers@bellsouth.net ] Enthusiasts soon understand each other. --W. Irving.
Are you an enthusiast? If you are out to describe the truth, leave elegance to the tailor.
Albert Einstein
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16:49:46 02/15/07
