Muffler mod etiquette.

[sean donato]

I know exactly how a tuned exhaust works, and how the physics do not apply in any way, shape, or form to a can muffler.

 

[CJ1]

I only had 1 that was obnoxiously loud, I ended up putting a muffler Randy modded for me on it as my ears don't handle loud noises very well anymore. I am probably not the best neighbor in that department as a 15:1 open header big block on the trans brake at 5500rpm "maybe" a bit louder that any saw! But I am very careful to run it only during the day and inside the garage. A friend that lives a quarter mile or so away know when I am running it. CJ

 

[bwalker]

I only had 1 that was obnoxiously loud, I ended up putting a muffler Randy modded for me on it as my ears don't handle loud noises very well anymore. I am probably not the best neighbor in that department as a 15:1 open header big block on the trans brake at 5500rpm "maybe" a bit louder that any saw! But I am very careful to run it only during the day and inside the garage. A friend that lives a quarter mile or so away know when I am running it. CJ

I use to love loud motors. At 47 I have 90% loss in my left ear and my right isn't much better. I no longer like loud noise! It sets off my tinnitus and is just annoying.

 

[RCamo]

I have a bark box for my 400C. It makes more power for certain, but is obnoxiously loud.

I put a header pipe on my 261 (non-electronic) from Egan and it seems that there is a significent difference in performance, hopefully running cooler too. But like yours, very loud!

 

[Tomos770]

That motor has a tuned pipe. A saw doesn't not have any such thing.
What @sean donato said was spot on in every regard.

To me....it looks like Husqvarna at least tries to "mimic" tuned pipe with that pear shaped exhaust....?

 

[sean donato]

To me....it looks like Husqvarna at least tries to "mimic" tuned pipe with that pear shaped exhaust....?

There's zero reason and no evidence to support that idea. One it's a stratto charged saw. Extremely little to zero useful fuel/air mix is leaving the exhaust. 2, there is no area (s) shaped remotely like a forcing cone where you would get the reverse pressure/ sound wave to "push" any fuel/air back into the cylinder to "super charge it."

 

[ballisticdoughnut]

I’m pretty conservative (for the most part) when it comes to muffler mods. First pic is a 026 muffler I opened up, screen was reinstalled. Second is a 288 muffler I reworked for my 181.

 

[bwalker]

To me....it looks like Husqvarna at least tries to "mimic" tuned pipe with that pear shaped exhaust....?

A pear shape isn't going to make an resonance effect, so no.

 

[huskihl]

Smaller exhaust holes seem to build pressure in the can and hold some charge in, giving the feeling of added torque. Big holes are better for all out rpm and hp. Somewhere in the middle works well on a work saw

 

[stihltech]

Just a tech, only ever ported 1 026, but it definitely ran well piped.
The one saw I have proven will run better when the muffler is slightly modified is the 026 Pro, MS260 Pro. The muffler only has one 5/16 (8mm) hole on the outlet case. Two more 5/16 holes will get the high side to lean out some more and be right in the wood EVEN with the fixed hi speed jet (no adjustment). Done about 12 or so and improved every one to where the saw sounded good and cut much better.
Also my ported 064/066 Hotsaw I ran for a few years. Opening up the muffler made a huge difference, but It only needed to run less than 10 seconds (on a bad day).

 

[dankas]

There is something to be said for quiet tools

So true, if only for safety** ... just how loud is the mod going to be? Has anyone put a sound force meter to a before & after ? I know just using an 'app' on your mobile is just a wild-ass-guess (needs to be calibrated...) and we won't be id a sound isolation box like Stihl displays in promo but really how loud?

Some makers do publish sound force #'s, Husky quite detailed, other's not so much... General stats rate gas chainsaws at 120dB sound force, said to cause damage in as little as 5 minutes exposure.

I also have age-related-hearing-loss, use hearing aids but Tinnitus takes comprehension to just below 50% per audiologist exam (close-captions are a blessing!). @bwalker if you ringing-T isn't continuous, your doing ok - for now. Mine's not due to chainsaw noise (say, is it interesting that when a saw is operating on youtube CC reads MUSIC - so true!)

**To the question of Safety** : at what distance from an operating saw is it safe to have ears unprotected? I use battery saws as well at gas operated...if you get a 20% improvement in operations does that mean a log you might have cut before at 60 seconds is now 48 seconds? Not trying to compete in this just to be safe as one can be and learn how to keep doing that.

 

[rogue60]

Omg a muff mod on a chainsaw doesn't have to be stupid loud you can get good results keeping things sensible.

 

[bwalker]

Smaller exhaust holes seem to build pressure in the can and hold some charge in, giving the feeling of added torque. Big holes are better for all out rpm and hp. Somewhere in the middle works well on a work saw

I agree. I like a moderate muffler mod in the stock location with a screen. Only use a screen because we have to deal with the Forest Service here. That and it's bone dry most of the year.

 

[farmguywithasaw]

Dyno joe made a video about muffler mods and crazy pipes and stuff, not expansion chambers in this video. However the pull that made the most power was when he removed the muffler completely. So hack away you can’t make it worse lol can’t find the video though

 

[huskihl]

Dyno joe made a video about muffler mods and crazy pipes and stuff, not expansion chambers in this video. However the pull that made the most power was when he removed the muffler completely. So hack away you can’t make it worse lol can’t find the video though

Makes more power, yes. But when you get on the dogs, they will bog much easier

 

[dankas]

I agree. I like a moderate muffler mod in the stock location with a screen. Only use a screen because we have to deal with the Forest Service here. That and it's bone dry most of the year.

Screens- YES, ALWAYS-Especially in your area!!
It would be a sorry day you might receive a certified letter or a Sherriff serving a bill for a wild fire...
Spark Screen - Always...

 

[PV Hiker]

Even with a screen you can start a fire. I almost did twice with dry flaking bark with hot muffler against the wood. Second time was a fireman from the local city volunteering with me, I let him put it out.

See if the 14 second video upload works.
.
View attachment 1000010697.mp4

 

[dwaugh]

I know exactly how a tuned exhaust works, and how the physics do not apply in any way, shape, or form to a can muffler.

I don't know anything about exhaust design, but isn't the volume of the chamber the relevant part as far as resonance is concerned?

 

[sean donato]

I don't know anything about exhaust design, but isn't the volume of the chamber the relevant part as far as resonance is concerned?

the entire pipe design is relevant. It all works together to achieve the correct wave and timing for how you want the engine to preform and at what rpm the pipe is most efficient at. Something as simple as changing stinger placement/ size has a great effect on the engines performance, let alone the effects of main chamber volume/length and forcing cone size/ angle.

 

[RedneckChainsawRepair]

Brian aka timberwolf did a whole thread here years back with testing and his dyno back in the day here on a 026. You can go super big before any issues arise.
Just search for thread. it will open your eyes for no believers.

Heck seen 18-23% gains just on 30min muffler mods on 290-390. Those are really choked bad. 290 worst.