| Lets work out the math to see: Vsoundinair = 331.4 + 0.6Tc m/s At 600C EGT, the speed is 2288ft/s.
At 800C EGT, the speed is 2688ft/s. The distance from the front runner to the collector is ~11" (measured with a tape measure through the inside of the manifold). Lets consider the amount of time between each exhaust event at a couple of different RPM: T = 240 / (RPM/60) * 360 4000RPM: 0.01s
5000RPM: 0.008s
6000RPM: 0.0066s
7000RPM: 0.00571s At 600C, the pulses are moving 2288ft/s, or, 27,456"/s
At 800C, the pulses are moving 2688ft/s, or, 32,256"/s At 600C and 4000RPM, it takes the pulse 0.0004s to get to the collector. The pulse would actually be able to bounce back and forth 25 times before the next exhaust event begun. Even at 7000RPM, the pulse reaches the collector at this EGT about 0.0017s before the next exhaust event. At 800C, it takes 0.000341s to get to the collector, which is even quicker than at 600C. I could further work the math here, but it is clear that the pulses are getting to the collector before the next exhaust event, even at 7000RPM. However, I only worked the math to entertain your thought. The reality of it has very little to do with exhaust pulse timing in a turbocharged configuration given that the turbine itself acts as a buffer to these pulses and virtually negates any sort of port/runner tuning that you can achieve with an NA setup. The primary factors at work in the manifold are how well it flows and how well balanced each runner is to the others.
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16:49:46 02/15/07
