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muffler mods

Started by musky111, March 11, 2004, 05:14:14 PM

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musky111

i've read some of the posts about muffler mods, and how they improve the performance of the saw??? how true is this??  and if it does give you more noticeable power, HOW DO YOU MODDIFY YOUR MUFFLER??? i'm sure there is more than just taking out your spark arrestor.  please let me know i'm intrested in trying in.
thanks, musky ;D
 
p.s how do i get a walker muffler???

Minnesota_boy

Two cycle engines do not use the piston to push out the exhaust, so any restriction in the exhaust stream will degrade their performance.  When you modify to increase the flow of exhaust, you also have to adjust the carburetor to avoid running lean.  Modifying the muffler can mean opening a larger port on the outlet of adding another port.  Power will increase as will the noise level.
I eat a high-fiber diet.  Lots of sawdust!

Kevin


oldsaw-addict

To put what has just been said into plain english, you adjust your saws carb a little bit richer on the High speed screw, then you can either order a modified muffler from the factory if you have a stihl, get a saw builder to do it for you, or yu can get the drill or dremel and drill/cut additional holes in the muffler to reduce exhaust restriction. I did it to my jonsered 670 with a dremel, I cut 2 square holes in the fron of the muffler that drastically increase the flow and HP as well. Modifiying the muffler will allow your saw to run abour 20 degrees cooler give an average of about 1/2 HP gain, and by allowing the saw to run cooler increase the life of your saw. Just make SURE you adjust the high speed needle on your carb a little richer than the original setting was, that way you dont burn up your engine and have to buy a new saw sooner.
Let there be saws for all mankind!

Oregon_Rob

What saw are you thinking about?
Chainsaw Nerd

oldsaw-addict

Who are you asking? I was talking about most saws in general.
Let there be saws for all mankind!

Oregon_Rob

I was asking Musky. If he has a specific saw in mind, we might be able to offer more specific help. :P
From his name Musky111, one could guess that he might have a Jonsered 111, which would most likely not need a muffler mod. If he is talking about a newer saw, we may be able to provide some specific info.
I modified my 372 and had great results.

Rob
Chainsaw Nerd

musky111

this is musky111 , the musky is what they call me at work because i live for musky fishing here in MN. the 111 is for the john deere tractor i rebuilt this winter.  Thanks for your info.  I wan't to mod a stihl 029.  how much should i richen it up?? how big of a hole should i put in?? I work with laser, and waterjet  cnc's so putting a hole in is no problem, just woundering if a certian size is recomended??? or am i wasting my time with this size saw for a mod???
 
THANKS for all the info i apperciate it very much..
keep buzzing!!!!!

Oregon_Rob

Well that helps a lot. I am sure that you will pick up some power by opening up the muffler on a 029. I will let one of the other, more smarter saw guys make the recomendation. In my case, with a 70+cc saw, i cut a slot 7/16 x 1-1/8" and adjusted the hi end screw until i could just hear the saw start to "4 stroke" I think is the term, and then back off just until it stopped. Again, Dan or Russ or ..... will give you a more percise answer.
Water jet would sure be a slick way to go!

Rob

Here is something http://www.arboristsite.com/showthread.php?s=&threadid=5626&highlight=029

Chainsaw Nerd

Sawyerfortyish

I just thought I would add my 2 cents for anyone opening up there muffler. Take the muffler off the saw before you try it. Blow it off good with air before putting it back on. Any metal fileings or grinding dust that gets in the cylinder can do some real damage to the piston and cylinder.

redpowerd

i really beat the crap outta my 029 muffler gettin it apart. looks like a bear got to it, but its back together with no rattles. the 32 and the 21 was much simpler
NO FARMERS -- NO FOOD
northern adirondak yankee farmer

musky111

REDPOWER, HOW MUCH DID YOU OPEN UP THE MUFFLER ON YOUR 029?  WOULD TWO .250 HOLES IN THE END OF IT DO MUCH FOR POWER GAIN?
THANKS.

jokers

The first thing you want to do in a muffler mod is to port match the muffler, gasket, and cylinder. This means that you inspect the individual components to ensure there is no overlap of material into the exhaust port of the cylinder.

How much you want to open the muffler is a subjective and specific amount depending on the size of the exhaust port on the barrel at the very least, but also taking into account the amount of transfer port area internally. A good place to start is an opening equal in area to the cylinder exhaust port and working up to 1.5x that area. Saws like Stihls that typically have less transfer area benefit from having less free open area on the muffler. Start at 1x the port and work up if that doesn`t satisfy you. Remember though, it`s alot harder to put back than take away.

Russ

woodsjunkie

Remember though, it`s alot harder to put back than take away.
 
Good point Russ and remember just because the saw is load doesn't mean it's cutting faster.
I have found some guys that think louder is faster Not true.. I have a saw that the muffler port is way to big and it actually slowed the saw down.
Your allowed to have an excuse, you just cant use the same one twice.

oldsaw-addict

I ran my poulan without a muffler one time, it really did suck at power, I had the clutch slipping a lot the power was crap, and I think it had too much power for the clutch it had at the time. My point is that you need at least a little bit of back pressure in the exhaust system to keep your saw running to its FULL potential.My j-red has 2 -1/2" holes in it and I have yet to have a problem with it.
Let there be saws for all mankind!

Rocky_J

I agree, WJ.
Good advice, Russ, but I would recommend slightly smaller openings. I recommend making the exhaust outlet equal to the cylinder exhaust port or maybe a hair bigger. Last year I worked on two Stihl 026's and on one of them I opened the exhaust too much. I had it opened about 1.25+  times the exhaust port. The other saw with a slightly smaller muffler outlet was stronger.

I've never tried to redesign a saw or muffler, just tried to put it back closer to the original design before the EPA mandates. Current saws are NOT built for maximum power, they are built for EPA emissions requirements. Almost all current saws are weaker than their older siblings due to EPA mandates. Anyway, I simply try to open up the existing outlets rather than redesigning the muffler and adding holes wherever. Use the existing outlet and make it bigger. If the muffler has internal baffles, cut them out. It's just that simple. Let the saw breathe a little, like it was designed to.

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