I don't believe any stuffing is going on in a non tuned saw muffler. Even with a tuned pipe the outlet doesn't even make a differance. For instance there are tuned pipes that have the outlet exiting from the fat section of the pipe instead of at the traditional end.
Bark box performance on Stihl MS362 M tronic?
- Thread starter Ranger-692
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In the first place the bark box was on the market first and the straight shot is a rough copy. The straight shot also aims exhaust directly into the side of the case and there is some anecdotal evidence this has caused failures. The bark box is also made out of stainless and tig welded. The breakage from what I read was caused by bad welds and was fairly limited.
To be clear I own neither, but the cheerleading of how much better one is than the other is a joke. The bark box is just better designed straight shot with a bit less opening area.
As for the the noise issue. You do realise that you once you get so loud even plugs and muffs don't protect you?
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Has to do with the small inner ear bones that get rattled by the sound concussion, even though the ear canal is blocked. All noise does damage over a long enough time, whereas extremely loud does so in a much shorter time. Most people don't realize this till it is to late. And some people don't realize this even after the fact. My chainsaw neighbor has advance hearing damage due to chainsaws and gun fire, and yet has not changed his habits one bit. He's only 38. I predict he will be completely deaf by 40.
That and just exceeding the protection factor of the hearing protection your using. It's not like you can subject your self to any sort of noise just because you are wearing ear plugs.
"I don't believe "stuff also, but muffler design is well documented otherwise we could just pitch them when tuning a saw. Pulsations do supposedly produce back pressure which delay unburnt charge from escaping the cylinder .
Other persons smarter than me have done the science on this .
Dieselshawn
ArboristSite Operative
I’ve got about 20 tanks of gas through the 661 and 660 saws, also one 500i on my dyno.
Open outlets through the cover don’t make as much power as a large side exit opening does. Also, the side exit is a bit quieter.
No muffler at all makes more power than a factory complete muffler with internal baffle but not as much as a large side exit opening with no baffle. Also stupid noise. Unless you love watching the cackling blue flames shooting out. Or a forest fire.
I haven’t seen those aftermarket front covers yet personally other than what I see on here. Be interesting to test them.
I save my money and work with the factory muffler to make power.
These saws do use mufflers to do the final tuning as well as carb tuning.
Open outlets through the cover don’t make as much power as a large side exit opening does. Also, the side exit is a bit quieter.
No muffler at all makes more power than a factory complete muffler with internal baffle but not as much as a large side exit opening with no baffle. Also stupid noise. Unless you love watching the cackling blue flames shooting out. Or a forest fire.
I haven’t seen those aftermarket front covers yet personally other than what I see on here. Be interesting to test them.
I save my money and work with the factory muffler to make power.
These saws do use mufflers to do the final tuning as well as carb tuning.
Probably just a tad more pressure inside the can holding in a little bit more charge. I don’t really know why either, it’s all guesswork for me
Back pressure and pulsing are two different things. A muffler can and does produce back pressure. It does not produce a pulse wave like a tuned pipe.
Note the results in the link. The SS has alot more muffler outlet area than the BB as such I bet torque falls off more so with the SS than the BB.
Yes to the little bit of back pressure, as in psi though, not sonic. For the speed of sound to take affect, you need somewhere in the neighborhood of 20-25 inches to the back of a reflective cone to be right. And that’s not happening in a muffler
RED-85-Z51
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These statements make 0 sense...
You state no muffler makes more power than factory, that open outlets in the cover dont make as much power as a side exit..then state you have never operated or seen either of the 2 dominant open muffler covers?
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I think he means running the saw on his dyno with no cover makes more power than the factory box-stock setup. And that side outlets produce more power than a front outlet.
He has tried his own front outlets, but neither of the two we’re talking about
Dieselshawn
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sbhooper
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I do not understand how you come to that conclusion, especially since you have never run one. The torque does not fall off more, based on all tests. My 400 is about as good as it can get, without doing a port job-which I am not going to do, as it is fine now.
That's not been the expiereance of several other reputable people.
sbhooper
Addicted to ArboristSite
Believe what you want, your money. Just don't knock it, if you have not tried it.
I don't need to run a straight shot to determine that the piece has a poorly designed out let that blasts exhaust into the case and that it's obnoxiously loud.
Ive heard them and they are noticeably louder. When I first started messing with saws I was opening them up left and right, replacing can mufflers on HOMELITE SXLAOS with stack mufflers. Then that got old quick. A sharp chain makes the biggest difference in cutting speed. That and having multiple saws in 40, 50, 60, 70, 80 and 90 cc increments means I have the right saw for the job (not that most people fall into that category).
Ranger-692
ArboristSite Member
Wow…I see that’s a side muff mod. Have you dyno’d a 362 with a bark box? Results? Thanks for posting!
