Just another junk chainsaw

[LD1]

I'm kinda wondering if it's not specifically back pressure, but kind of like you mention in you last sentence, creating a pulse in the exhaust and intake so that the intake charge piles up against the back pressure, just before the port closes and goes into compression, and the opposite when the exhaust port open, it's being sucked out. I'm sure there is a vocabulary to describe this.

Backpressure itself is incorrect vocabulary to describe it.

But there is no "tunning" in a chainsaw muffler. Its simply an expansion chamber that allows (for lack of better terms) and time delay release of exhaust gasses to quiet the sound. Nothing more.

If back pressure really were a good thing....muffler modding a chainsaw would be a bad thing. But it isnt. Open up the muffler and you can notice the results on a chainsaw.

I have said all I can about this topic, so as far as Im concerned....Im done discussing because there is no point arguing til we are all blue in the face and then walk away with the exact same opinion/notion in our heads.

You can google the topic.....its discussed at length. Some think backpressure is good, others do not. To each his own and Im not trying to convince anyone, just educate. Do your own research and make up your own mind

 

[Snobdds]

I think back pressure is rooted in the physics of the two stroke motor. Take away the back pressure and all the torque goes away as all the compression leaks out before the detonation event happens at the correct time.

 

[5030]

In reality it all has to do with port timing and scavenging. Lots of differences between an expansion chamber and a chainsaw muffler.

 

[yomax4]

Back pressure or no back pressure. I did muff mods on 3 saws. 026 pro, MS361 and an 044 mag. After the mods each of the saws were tuned and were a bit louder but each performed like the next larger saw than what they were. No regrets.

 

[Snobdds]

muff mods are just defeating the EPA noose.

There is still backpressure present...it's not like a muff mod deletes the backpressure.

 

[5030]

Don't bother me at all. I wear muffs.

 

[xyz123]

NLA new and hard to find use rubber av's for the poulans like ones fixed shown in thread. I still have plenty of used and some NOS still. But other folks dont. Soooooooo =

Had a idea for years now that different makers may work. Think I found a winner. The bigger ones didnt work but the smaller were close to same size.

 

[5030]

Thar cover needs a bath...lol

 

[xyz123]

Thar cover needs a bath...lol

Parts saws none of them getting a bath.

But if your volunteering

 

[5030]

Not me. No parts saws here, I use them all except the 090 Stihl.