What is a modded muffler on a saw?

[08brute]

Hey people! Im new on this site and fairly new to heating with wood (going on 2 years). I keep reading about modded saws and modded mufflers. After failing with the search feature i decided to start a new topic. Can anyone tell me what a modded muffler consists of? Can you do this yourself? Is it harmful to the engine?

BTW - A little about me-
i have a stihl MS270 20" and just picked up a used Stihl 023 16" for $65. A buy that i am pretty happy with since this thing runs great.

I heat my house (3000 sq ft) and my garage (1000 sq ft) with my US Stove Co. 1600 tied in to my existing propane furnace and duct work. I put my wood furnace in my garage and ran return air and ducting through the fire wall. Less mess in my house this way. The only problem i face is pushing warm air through 100's of feet of duct and keeping the pressure up. Thats a work in progress though.

Thanks in advance!

 

[smokinj]

far as the duct work there is a few ways to do it.1 is to increase the power of the blowers by going with a bigger one2.inline duct booster and a powerful one

 

[smokinj]

modding the muffler is pretty eazy,but you have to take the limit caps off

 

[mike1234]

My set up is basically the same, in garage pushing about 100', heating about 4800 sq ft. Seems like low air flow, but keeps the house warm hot so don't care if it flows as fast as propane furnace.

Basically a muffler mod is:
1. Take off muffler, make the exhaust hole at least twice as big. You can get fancy with this, or you can drill a bigger hole.
2. Adjust the carb to be much richer. This require removing the stops covering the actual screws. If you don't do this right, you will burn up a piston.

My 270 I did a few weeks ago, after it went out of warranty, really increased the power. Did my 290 a year ago, again really increased the power. It does make the saw MUCH louder.

The other things to look at before doing that, if you still have safety chains, go to full chisel chains, that is a way to make your saw much more efficient.

 

[Nonprophet]

Here is all you need to know about muffler mods--and then some! lol

Note that there are after-market duel port mufflers available for many makes and models for about $50, check Bailey's to see if they have one for your saw. A word of warning, most of the duel-port mufflers for sale on feeBay are WAAAAAAY overpriced........


NP

 

[kenny chaos]

Any "lame-o" can drill holes in the exhaust.
What will really help is while you have the muffler off, stick your finger in the exhaust port and you can feel
edges from the casting. To advance to being just "lame", take your dremel and remove these edges while thinking about least resistant air flow.
Now take off the carb and do the intake side of the cylinder also.
For god's sake man, don't get any filings in the motor.
This minor stuff will help a lot.
Then there's the "A" types that gouge out half the cylinder for max flow. This takes a lot more knowledge.

 

[ROBERT F]

Muffler mods can be good, but you will need to richen the mixture up after the mod, and increasing exhaust flow to much can cause over scavaging, and rob the motor of lubrication. as well as allowing the motor to over rev. this happens on two strokes where crank/rod bearings are lubed with the oil from the mix. and going to big on the exhaust can also take away from the bottom end power, not that saws use alot of bottom end power, but you gotta get from idle to operating speed somehow!

 

[mike1234]

ok, So I am a lame-o, well I did a little work inside the 290 muffler, can't get inside the 270 muffler, so that makes me a "lame-c" (a c begin half of an o in case my humor falls in the lame category also), but even a lame-c job really made a difference.

Any "lame-o" can drill holes in the exhaust.
What will really help is while you have the muffler off, stick your finger in the exhaust port and you can feel
edges from the casting. To advance to being just "lame", take your dremel and remove these edges while thinking about least resistant air flow.
Now take off the carb and do the intake side of the cylinder also.
For god's sake man, don't get any filings in the motor.
This minor stuff will help a lot.
Then there's the "A" types that gouge out half the cylinder for max flow. This takes a lot more knowledge.

 

[colebrookman]

Any "lame-o" can drill holes in the exhaust.
What will really help is while you have the muffler off, stick your finger in the exhaust port and you can feel
edges from the casting. To advance to being just "lame", take your dremel and remove these edges while thinking about least resistant air flow.
Now take off the carb and do the intake side of the cylinder also.
For god's sake man, don't get any filings in the motor.
This minor stuff will help a lot.
Then there's the "A" types that gouge out half the cylinder for max flow. This takes a lot more knowledge.

'
"Ported and Polished" that goes with Jag's "Run what you Brung". Cheers for us old guys. Be safe.
Ed

 

[Jags]

"Ported and Polished" that goes with Jag's "Run what you Brung". Cheers for us old guys. Be safe.
Ed

When it comes to making an engine run - don't ever underestimate the old fat guys (especially if he has gray hair). Learned that when I was running some mighty powerful 2 stokers on 4 wheels.

 

[08brute]

Thanks for all of the advice guys! I am going to at least cut the screens in my muffler. I think my 023c has some carbon build up.

 

[08brute]

One more question...

If i want a chisel chain on my 270 do i have to change the bar? I was told that my current bar will not work.

 

[mike1234]

Never heard of such a thing. Unless your bar is just plain worn out, and as long as you are using the chain made for your bar (stihl bar, stihl chain) the same bar running the safety chain runs the full chisel chain.

 

[computeruser]

One more question...

If i want a chisel chain on my 270 do i have to change the bar? I was told that my current bar will not work.

Huh? No. If gauge and pitch and drive length count are correct, the saw and bar couldn't care less what sort of cutter profile you're using. With a 270, you're likely .325" pitch, .063" gauge and whatever number of drive links corresponds to whatever length of bar you're running. There are plenty of cutter profile options in this chain type. Stihl RSC would be fine, or the Bailey's WP equivalent, or the Oregon 20-series stuff. All will be good cutters, faster than semi-chisel or the safety crap that likely came with your saw. If you exclusively hand-sharpen, the Oregon stuff is a breeze to touch up freehand. As for that Stihl Green versus Yellow bar/chain crap, it is irrelevant from a function point of view.

As for muffler modding, there isn't much to it for a worksaw. There is no need to polish intake or exhaust ports, or to get into the saw, unless you really want to (and know what you're doing). Simply opening the muffler back up to what it should be (rather than what the EPA thinks it should be) will help substantially. Modern saws are choked down past the point of logic in the name of emissions and noise reduction, and the performance suffers profoundly for it. The incremental gains to be had from subsequently polishing intake and exhaust are minor. If you want to enlarge them or change their shape, or start modifying transfer timing/size or interior profile, then that's a different game altogether - gains can be profound, but mistakes are expensive.

I can't recall offhand what the muffler on the 270 looks like, but if it's anything like the 290, you can remove the front baffle and screen, open up the hole a bit, trim/bend the baffle as necessary, and reattach it. Keep the screen, unless you have a good reason not to, if only to keep #### from falling into or making a nest in your saw. I run a screen on most of my saws, and think they're a good idea to have.

 

[Tony H]

i have never modded a saw but I do have dual exhaust on my splitter!