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Old 02-12-2016, 10:53 AM   #106 (permalink)
Shawn D.
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Originally Posted by freebeard View Post
Fair enough. But it wasn't falsified (I think). There was a post between #90 and #91 that I replied to, that has since been deleted.

It might broaden the rpm range it's effective in or weaken the overall effect. Hot rodders would test this on a flow bench.
A flow bench is a constant-state test. For exhaust systems, the tests are done on a dyno on a running engine, not a flow bench, as a dyno is dynamic. In an exhaust system, the key word is "system" and the effects must be tested against multiple dynamic branches, not an isolated component in constant flow. You cannot test scavenging, reversion, wave travel, or effects on other cylinders by using a flow bench.

While I think your point about the relative volume of branches is valid, I do not believe your point about the smooth radii is. The real reason the radii are smooth between blood vessel branches is structural. Any time you have a "notch" between two components with a sharp transition, that's a high-stress area that can lead to failure. It's true for real "branches" on trees as well -- any tree (like a Bradford pear) with sharp notches between a trunk and a branch is much weaker and are more likely to fail with high wind or snow load. This is also the reason for structural fillets that are added for no performance-related reason, as well as the purpose of "stop drilling" a crack to stop its propagation.

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