Yes I understand that is the traditional line of thought.
The whole saw felt like it was geared around trying to make half decent power while being severely emissions restricted.
The small exhaust port, 10 to 12 deg of blowdown and visible signs of burnt gas back feed into the transfers is odd.
Then stuffers to try and push against this harder?
Im doing this to see what the saw does..... Sometimes we need to think outside the square..... Its worked for me before.
My intuition says its going to run well.
It wont ever be a world beater with the little low top filter but I am looking forward to running it beside my ported 371
I’m curious how this 570 will perform with longer bars.
Gotta work on them legs Tony, a bit too thick for a porter.Runs nice
Might be a while before it sees timber though, we are badly flooded here at the moment.
It will be wearing a 20" bar, we don't run much more on them here as they tend to struggle a bit in our timber.
Was having a laugh earlier thinking when I run it, I will then wonder how it would go with the stuffers installed haha
I like removing the stuffers, I feel they block lube from bearings, and have no issue with increased crankcase capacity typically.Yes that's all the known and widely followed guidelines, but its all too rigid, "walk between the lines or else" for me.
I think there is more to the dynamics than that.
Time will tell, it may fall on its face, but there was only one way to find out.
At least I know the bearings are getting oil
Toss a 28” on it and noodle something for science. Or just lean on the 20” extra hard. If it has a low gear you’re on to something. There are a several 5-series saws that I wish had more bottom end power.
I like removing the stuffers, I feel they block lube from bearings, and have no issue with increased crankcase capacity typically.
One question I will ask is that since your case volume is now much larger, should intake be dropped in order to fill the large space? Or better to keep it high to really squeeze what does enter?
personally I don’t mind a low intake
I tend to like less intake.
I think people lower the intake chasing power, and it may work in sone cases but for how I port a saw, I find less works just fine with my porting.
Remember it’s not just time to be considered.
Area plays a big role in power band and more area can mean less velocity at lower rpm under load.
I find velocity for short time works better than a big lazy hole
Be VERY CAREFUL, I went too far and ground a hole in the case while doing this.For science!
I was thinking take this part away if you left the stuffers.
View attachment 342769
But better to try both!
The idea behind the stuffers is that more case vacuum is built when the piston is on its way up and more pressure is built on the way down before the transfers open. The results are a higher but narrower rpm hp rangeKinda late to this reply, but in late 2020 or early 2021 I built a 576xp non autotune without the stuffers running a 575xp crank and piston (which has holes in the strato cutout that the 576 doesn't) in the OE stock 576xp cylinder, sold the saw to a buddy sporting a 24" .058 Oregon bar and chain, was amazed at how it ran, gobs of power.
In my adolescent wisdom of thinking I believe the stuffers were installed along with the Stratos Charging as a way to meet the EPA Emissions Standards at that time, a smaller area equals a smaller fuel charge which will equal less emissions, also it kinda unshrouds the PTO side bearing for better oiling, But hey what do I know.
What I do know is the saw was easier to tune and was able to open the main jet further than what I was on my stock 575xp, before it started 4 stroking, so in my opinion with the stuffers out there is more volume area to fill equally with air and fuel and that will directly result in a more dense charge into the cylinder resulting in more power. But again what the hell do I know.