[mechman600]

A very interesting topic...still. To better visualize it in my head, I paintbrushed a crude diagram. Hopefully the attachment at the bottom works for you.

From what I see, Andyman is right. In theory. Retarded = lower dynamic compression and lower pumping losses like the Atkinson cycle, and also a larger expansion ratio. Advanced = higher dynamic compression and higher pumping losses but lower expansion ratio. 1/2 dozen one, 6 the other. All theories, so I appreciate the stories of people actually testing the results. In reality, how big of a difference will it make if I retard/advance (depending on who's right) the cam timing? 5%? Who knows.

Does anyone know of a manufacturer who makes "economy" cams for a Honda D17A1? I really doubt it as all I can find is high performance ones.
Super low duration and little valve overlap would be good. Wait a minute...how about high-perf cams made for forced induction....they have very little valve overlap and less duration than typical high perf cams, but lots of lift. Would one of those work in an economy minded engine?

[edit] Nevermind. I just looked at some specs for forced induction race cams and they have waaaay more duration than stock ones. I should have known.

James