E. I'm with you on that. I've not been in a death egg for some time and hope not to again.
Edit: I dug out my old books to look into this further. I measured my Enstrom exhaust and all calculations are based on that engine as I have the details to hand. It is a 360 running at 2900 rpm.
Basically the exhaust is too short to have any bearing on gas scavenging. All major resonance, extractor and gas slug effects are over by 18 degrees of crank rotation after the exhaust valve opens. By BDC the pressure in the exhaust will be just above ambient. This means that for the rest of the exhaust stroke the cylinder is acting simply as a compressor. By calculation, to empty the cylinders at sea level will require about 25 BHP. At 5000 feet density altitude 6 BHP less is required. so 6 BHP more is available for the same manifold pressure assuming the combustion event is the same. I do not know for sure how much power is lost due to enrichening. My guess is more than 6BHP. Draw your own conclusion.
Last edited by Gaseous; 20th May 2006 at 14:17.