Muffler Mod

[Duffyfiveo]

Hello, this is my first post, though I've lurked here awhile. I am getting ready to purchase a Stihl MS261 C-M, and I am likely to mod the muffler.
I'm sure this has been answered before, so I apologize in advance: Does a muffler mod allow the saw to make more power, OR is it just more responsive and quicker revving? What kind of power increase is typical in a 50cc saw?
Thanks!

I've learned a lot here!

 

[Brian Carlson]

In my experience a muffler mod will help both power and throttle response. Think of the engine as a pump . The better or faster you move air through it the better. Don't expect it to run like a ported saw but I usually feel more torque and get a few more rpms out of it when returning. Make sure to retune because it will be running leaner with higher air flow. hope that helped a little.

 

[astnmacgto]

Yep he is right, an engine is only as good as its ability to remove exhaust gasses from the cylinder, the better the exhaust can remove the gasses from the cylinder the more fresh fuel air mixture can drawn In for the next power cycle. The only way to improve the exhaust other than an entirely unrestricted flow is to form an exhaust type where the previous exhaust pulse actually draws the next pulse out like a vacuum, called scavenging which is what a tuned pipe does. But to answer your question, yes it does both. Better exhaust flow allows more rpms as well as more power because there is less inert gas (exhaust) left in the cylinder when coming up to fire the next time.

 

[astnmacgto]

Hello, this is my first post, though I've lurked here awhile. I am getting ready to purchase a Stihl MS261 C-M, and I am likely to mod the muffler.
I'm sure this has been answered before, so I apologize in advance: Does a muffler mod allow the saw to make more power, OR is it just more responsive and quicker revving? What kind of power increase is typical in a 50cc saw?
Thanks!

I've learned a lot here!

aren't the cm saws auto tune? You will definitely want to retune after the muffler mod, which in that case I know nothing about the auto tune, does it allow you to base tune it by hand? That would be something to find out.

 

[Efisher26]

Simple louvers,and I dremel cut out the baffle inside (I know new models are a lot harder to mod) but this all I have for help examples

-•------------------------------------------------------------


Just a home owner that likes the older better made machines

Craftsman 3.7 x2
Husqvarna 36

 

[cus_deluxe]

aren't the cm saws auto tune? You will definitely want to retune after the muffler mod, which in that case I know nothing about the auto tune, does it allow you to base tune it by hand? That would be something to find out.

Yes,m saws are m-tronic, and dont allow for manual tuning. They will
Compensate on their own. Ive seen threads where mastermind had a 562xp that had 3 or 4 seperate massive air leaks and the auto-tune was able to keep the saw from melting down.

 

[astnmacgto]

Yes,m saws are m-tronic, and dont allow for manual tuning. They will
Compensate on their own. Ive seen threads where mastermind had a 562xp that had 3 or 4 seperate massive air leaks and the auto-tune was able to keep the saw from melting down.

That's fantastic, if it keeps super good track of the tune and makes sure it is not lean that would be the thing to have, as long as it doesn't have glitch issues I guess

 

[CBeal34]

I modded my MS261C muffler yesterday, copying Brad's method which he shared here.

http://www.arboristsite.com/communi...w-seconds-between-cuts-what-the.295092/page-5

He talks about muffler mod results on the MS261C Rev. 2 a little in this thread.

http://www.arboristsite.com/communi...-saws-meets-the-stihl-ms261c-ii.298040/page-3

While not as pretty as the job Brad did on my MS241 it definitely woke the saw up. There was a noticeable improvement in throttle response & torque while not significantly louder. Well worth the effort.

 

[blsnelling]

Does a muffler mod allow the saw to make more power, OR is it just more responsive and quicker revving? What kind of power increase is typical in a 50cc saw?

ALL OF THE ABOVE!

Stock in dry Ash.


Muffler Modded


Sorry, but I don't have a New Edition with Muffler Mod and Timing Advanced. Much different wood, so not really much help here.


Ported and Timing Advanced


Below are how I mode the muffler on both a 261 and a 241, as referenced by CBeal34 above. While you're in there, you might as well go ahead and advance the ignition timing. It's simple to do. Remove the flywheel and thin the key such that you can index the flywheel CCW about 1/4" on the OD of the flywheel.

 

[CBeal34]

Brad, how do you get the crisp angles on the three louvers in the 3rd picture? I couldn't get much more than an arch with wrinkles & was afraid of over-working & breaking them off.

 

[blsnelling]

I use a small Stihl tuning screwdriver to pry them up, then fine tune them with a real small pair of needle nose pliers.

 

[Duffyfiveo]

Thank you all for your replies! I am very excited to get my saw and will post pics!

 

[Deleted member 116684]

Modded my 362 cm today. Uh be careful not to direct exhaust to the wrong spot.Very important!

 

[Duffyfiveo]

I have watched a lot of videos on mufflers. In one, I looked at "The Chainsaw Guy" on youtube. He sells mufflers called "buckshot test mufflers". They look to be tig welded and pretty well made. I'm not sure on the price though.

 

[ferris076]

ALL OF THE ABOVE!

Stock in dry Ash.

The muffler Mod saw is not faster then the stock one