On a technical level, Mustang Mike is correct. The screen causes turbulence reducing air flow and gets worse with deposits. Also the mass of the screen mesh condensed down actually reduces your outlet hole. Your opening size with screen that is in your picture is no where near the size when these considerations are introduced. The actual size and locations of the holes actually would need to have a specialist engineer etc analyse and do performance tests. That is why the Stihl DP muffler that came stock on my saw in non USA versions are made the way they are. If I was going DP, I would get the stock OEM muffler. It would be interesting to see the test results of the noise to hole/s with screen combinations that I am sure Stihl engineers conducted are. How big can the hole/s get before noise gets too loud. I guess I could get a box of foam earplugs and hand them out to anyone that complains haha.
. Haha ha lol....not my thinking, it is from an article and that part is nothing. When it got to the ratio of exhaust port to optimum muffler hole size, I had enough and looked at pics. Top pic is mine and I do not even have the slot (sickening). I should get the bottom muffler from Stihl but do not know how loud it is. I have known this for 14 years! These guys will go on about muffler mods forever...look at all the old forums.
Actually the article explained that you measure exhaust port and tells you how by using sticks of spehgetti. You count sticks of spehgetti that will fit in port and then use, I think 80% of that number of spehgetti sticks to fit in the hole you are making. Then there is a percentage of exhaust hole port you should make muffler hole because too small and you are loosing performance and too big and your saw engine performance itself is being tampered with because it needs a certain amount of back pressure. You may be able to make your hole bigger so your saw has more powah and is louder and you cook your spehgetti...Wahoo! Not my thinking...I would be out there poking holes with a screwdriver until I felt good.
Yep, and I just took my cylinder out of my kit with piston out and put their muffler up to it. You can look through the non screened muffler hole and be looking at the cylinder seeings how there is no baffle. If I took out the spark plug it would be a toss up which way something could get in cylinder. I think the back of muffler may be smaller than exhaust port so there may be restriction right there. On my tractors, backhoe etc when they have straight pipe, I always put a flapper and off set free flow muffler so water etc does not go down to expensive places. I trust Stihl more than the Asians. It is a wonder the complete saws have not been banned yet.
I wonder on their completed saws if they have screen on. I also notice they state on completed power heads that they come with 6 month warranties but only as is and not touched (or something like that) ...are they saying putting a bar and chain on ends the warranty? I would give them a test run if warranty covers saw with bar and chain and they had service centers in USA (I have seen this done with Harbor Freight. Some guys would run cheap $100 generators than go get another one after messing it up...not really ethical). I bought a quality Chinese brand welder but it messed up under warranty. My recourse was to pay to send it to one of two USA Service Centers for $100s both ways and wait months to see if they could fix it or whatever....I heaved it and use my good old trusty Miller Legend.The Chinese have a rigged plan...where are you going to get saw fixed and who pays shipping. A Stihl 462 like you recommend is way to go using the rationale I need two big saw for rare breakdown back up.
This!
