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<blockquote data-quote="ossagp" data-source="post: 212552" data-attributes="member: 1650"><p>Heck, I figured you being a plumber, you would be &quot;up&quot; on pipes.&nbsp;&nbsp; Retarded valve timing and ignition timing is more beneficial to high rpm power than low rpm power.&nbsp; The engine is better able to take advantages of the faster travelling sound waves that determine how your exhaust system works with your intake.&nbsp; Short story:&nbsp; the pulse that tries to cram the fresh intake pulled through the head and out the exhaust during valve overlap moves at the speed of sound &quot;local&quot;.&nbsp;&nbsp; Retarding the timing raises exhaust temp, which raises pressure, which makes that sonic wave move faster.&nbsp;&nbsp; So you get more of the charge back in where it counts,&nbsp; and that increases the high rpm &quot;fill&quot; or increases the volumetric efficiency.&nbsp;&nbsp; Simple enough I should have figure it out myself,&nbsp; but I had to have someone else do that for me.&nbsp; Prime reason why the length of your exhaust pipe is as important as it is.</p></blockquote><p></p>

[QUOTE="ossagp, post: 212552, member: 1650"] Heck, I figured you being a plumber, you would be "up" on pipes. Retarded valve timing and ignition timing is more beneficial to high rpm power than low rpm power. The engine is better able to take advantages of the faster travelling sound waves that determine how your exhaust system works with your intake. Short story: the pulse that tries to cram the fresh intake pulled through the head and out the exhaust during valve overlap moves at the speed of sound "local". Retarding the timing raises exhaust temp, which raises pressure, which makes that sonic wave move faster. So you get more of the charge back in where it counts, and that increases the high rpm "fill" or increases the volumetric efficiency. Simple enough I should have figure it out myself, but I had to have someone else do that for me. Prime reason why the length of your exhaust pipe is as important as it is. [/QUOTE]

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