Thanks a TON for doing the #'s on this!! Was pretty sure the best bet was "modded OEM airbox with fresh HD2's", ie most economical & practical, it's nice seeing confirmation! I have a ~10sec clip that shows mine, don't wanna link here on your vid but you can get that extra flow to the air-filter *w/o* cracking the airbox (like yours where the bottom edge is now gone, that entire rectangle needs to mate-up for it to press the filter into the carb-wall properly), you can instead just open holes in the main airbox and line with filter-paper or whatever and not only get that huge increase in CFM potential, but it's pre-filtered so filter cleaning interval is *way* up!!
I understand your thoughts on air flow, but dont you get more chip build up with those holes. You say it gives it a spot for the chips to escape, but it's taking air in & not releasing air there. Am I wrong, cause my experience with it is I get a lot more build up with chips without air cover or with modded air cover?
in the summer if it's not raining I run no cover because I've noticed almost zero chip accumulation in the filter. As for the physics going on. I guess honestly I couldn't articulate what/why it's happening that way.
I have run with no cover many times. It's fine unless it's raining :). 404 just lasts longer. Stays sharper longer. Can take more beating. More meat so longer chain life. 661 has the power to pull it.
it adjusts to most changes to the saw just like it adjusts to environmental changes on it's own. Now if I took a stock saw and then did a muffler mod, air filter mod, timing advance, and ported the cylinder all at once I might do a reset. But generally unless I am having problems with the saw I don't do a reset. I've experimented with doing it quite a bit over the last 3 years and that is where I am currently at on the subject.
