Well if my numbers are flawed,show me any factory racing engine that has 180 plus compression,from the 70's to now.
4-stroke engines only make compression every 2 strokes,their compression losses are halve as much.
*The angle of crankshaft rotation is the same. The loss for compression pressure will therefore be the same. That the 4-stroke has to complete an additional rotation v the 2-st on a per firing stroke is absolutely irrelevant. Actually for something with a turbocharger, the exhaust stroke is also a load. The additional air volume to compress adds an additional load...and yet the compression pressure is as high as design octane ratings allow. Or for CI engines, it is an order of magnitude higher( 60 psi boost, plus 18:1 CR for a relatively tame street engine).
Show me any factory high performance 2-stroke where their compression is 180 plus. Any hot motor from 1970 to now. with 2-strokes the limiting factor was how hot you could get the piston before it melts.
*Just because it has not been done does not mean your thesis is correct. It means there is something limiting, but it is not pumping loss due to high compression pressure. And now you bring piston temperature into the argument? I thought you said it was pumping loss?
That's why some latest hot 2-strokes had an electrinic ignition that retarded timing at high rpms to prevent that. Show me some specs from modern hot 2-strokes that have that high cranking pressure from the factory. In the last 4 decades I have not seen any.
As for flaring an intake port outwards from the carb that means you are slowing intake velocity.
*And this has what to do with your thesis?
As for timing advance on 4-strokes same to 30,000???
*Read the paper. The short answer is YES. It was written by some Honda engineers, who were building 4-stroke 250's to compete with 2-stroke GP bikes in the early 60's. Ignition advance was not effected by RPM until about 30,000 rpm. There were conditions on this, as you will see after reading it. In a nutshell, it is why there are 8 rods for the NS750 V4...and 32 valves, and two spark plugs per 'cylinder'. Average piston speed limits demand a short stroke, short stroke means large bore...which gives a thin, disc shaped combustion chamber( since in this class the No. of cylinders is dictated by the rules). Disc shaped chambers are poor for flame front propagation, so make them other than circular...surely you are aware of the reasons behind the oval piston tech Honda developed? maybe? In any case, if the combustion chamber was not turned into a disc, the spark advance requirements did not require additional advance as rpm climbed past 10,000 rpm, or double...but right around triple more advance was required.
All the ones I worked on were about 8 degrees to 38 degrees,and very sensitive to rpm,barometric pressure,mixture etc.
Show me any factory hi-po 2-stroke engine specs with that compression...
*One more time, show me that it is pumping losses that dictate that...you started to cast your net wider when you brought up piston temperature....but that has zip to do with pumping losses due to compression pressure.
cheers,
Douglas