once I found in forums one URL to mazda engineer article about semi-pp and pp testing.. they tested varous port types,sizes and timings and filled results to tables. can`t find it now, could anyone remind please?

i am making PP now and want to select proper form and timing of intake and exhaust holes, just need some research data.

 

http://www.yawpower.com/dectech.html

Bottom page has the MFR PP timing #

 

That's one of the MFR port timing setups anyway... there's others. I'm the one who scanned that SAE paper; I was only emailing copies to people, but I just got it on photobucket.

http://i39.photobucket.com/albums/e1...E/90032/01.jpg is the first page, with the rest being... well, 02.jpg through 10.jpg. Not my work obviously, I've not done any testing with the numbers they published, etc... but I figure some people might be interested.

 

looks like a very interesting article... but from the first sight a bit complicated to understand.


maybe somebody could advice some timings that he used and that gave good results?
also what port styles do you use: circle, oval, D, square ?

am i right with theory:
1) too early exhaust open= less power since combusion power will not release all its power
2) too late exhaust close = more overlap
3) too early intake open=more overlap
4) too late intake open=less air will fill chamber due to not enough air velocity
5) too late intake close =air might go back to intake

thank you very much!