how much power will a muffler mod give you

[Ray Bennett]

I've read a few post on modifying the mufflers on the stihl 290's and the 390's. My question is how much HP will a Modification give you on these saws. I cut and sell about 50 cords of firewood per year (oak up to 24 inches) and usually my saws are plenty strong enough but once in a while I wish I had a little more power and this seems like and easy to get it. I was also wondering how much more power does a major mod give you from a smaller one. Thanks for the Help. Ray


STIHL 290 20 inch bar

STIHL 390 24 inch bar

 

[clearance]

Ray-no replacemant for displacement, if I was into Stihls and cutting that much firewood I would get a 460, or a big used saw.

 

[TimberPig]

Depending upon how choked it is to begin with, and how open it is at the end, and whether that is tuned well to the engine's needs, you will often gain about 0.5 hp. Some gain a little more, some a little less. You not only gain a little power, but you also let heat out of the saw, making it run cooler and longer. Don't forget to richen the carb adjustments up too, as the freer flowing exhaust leans out the air/fuel mix, and can burn an engine down if it is run too lean. For more information, try using the search function for muffler mods. There is even a good thread with pictures showing an 029/290 muffler modded, which is the same as on the 390 as well.

 

[rahtreelimbs]

I did a muffler mod on a Stihl 029/290 a few yrs. aago. The saw woke up quite well. This is one of the loudest saws I had heard in a long time!!!

see this:

http://www.arboristsite.com/showthread.php?t=15986

 

[Ray Bennett]

Thanks for the help, If it gives me .25 to .5 Hp I will give it a try. Belive me I will richen it up and put a tac on it to make sure it is tuned right. And yes I would like to buy a 440 or bigger saw but 700 bucks for a saw is hard to justify when it is only earning me about 3 to 5 thousand a year. One day I may get one but for now I will milk what I can out of the ones I have.

 

[fishhuntcutwood]

If it gives me .25 to .5 Hp I will give it a try.

There's no reason to not do it, even if power gains are negligible. Like was said, it'll get heat out of your saw, which is always good. That said, I'd expect a half hp or thereabouts from the saws you mention.

Jeff

 

[Diesel JD]

I just sold a friends 260 and I saw how mickey mouse the mufflers were on the 390 and 025 by com[arison they can't breathe! I am somewhat afraid to mess with perfectly well running saws, but I will eventually get up the courage to doa conservative muff. mod on the 390. The stock 260 muff is similar to what I'd liek to have when I am done...a lot more breathing room for the saw.

 

[manual]

I did a Muffler mod on my 029 and I feel It made a big Diff. Learned how to mod mufflers and adjust carbs all on this site.
If you want to start with a small mod go for it. But if you start to think like I did you will end up going with a bigger mod.
I also found it would be wise to go to your sthil dealer and get new muffler nuts and bolts.
Read on and have fun. Thats what it is all about.

 

[SmokinDodge]

It is definately worth doing. I opened up my 036 and fattened mix and it made a nice difference. I'm in the process of doing every saw I own except the woodshark, that thing is beast enough on it's own! .

 

[046]

think of muffler mods as the low hanging fruit.

these first gains are the easiest to achieve and can be had with relative little effort. gains after that take more steps. I'll let others with way more experience go into details...

main disadvantage is higher DB levels. some elect not to do muffler mods due to additional noise level increase.

for an example: I've got a dead stock stihl 064 with dual port muffler. yes, I could open it up, but since 064 has more than enough grunt in current tune. I've elected not to leave 064 alone in favor of a quieter running machine.

should I decide to do any amount of heavier work, like say milling. muffler mod would be the first thing that would happen.

 

[timberwolf]

From what I have found it has increased cutting speed by about 25-40% depending on the saw and chain you use.

Not only does it produce more HP but it also shifts the power up 500 to 1000 RPM or more in the cut. This gives higher chain speed and enhances any gains in torque/HP.

You will notice more gain with a sharp / square chain that will cut well at higher RPM than a dull chain that is lugged and pushed through the cut. That to say most of the gains are at the top end of the powerband.

 

[MS-310]

My 310 is sweet with the mod on it.

Its really really really loud, but thats the fun part. You will need ear plugs, Trust me.
More power
More nosie
More fun.
:rockn:

 

[casey v]

A muffler mod on any saw will increase preformance and help to reduce heat. How much depends on how badly the saw's muffler was restricted. I have been playing around with Poulan 2300CVA's. Great little saw with antivibe and with the Oregon lo-pro non safety chain, they cut real well. I find a lot of these saws at flae markets, garage sales, etc for a few bucks. I pull out the screen and one of the swiss cheese baffles from the muffler. Remove the cylinder base gasket and just use gasket maker (only two screws hold on the cylinder and in almost all cases the screws were loose to really loose). Retune the carb, and the saw really cuts well. I have run 16" bars on these saws fully buried in Doug Fir with no sign of bogging down the saw.:biggrinbounce2:

Mike

 

[jtc16]

A muffler mod on any saw will increase preformance and help to reduce heat. How much depends on how badly the saw's muffler was restricted. I have been playing around with Poulan 2300CVA's. Great little saw with antivibe and with the Oregon lo-pro non safety chain, they cut real well. I find a lot of these saws at flae markets, garage sales, etc for a few bucks. I pull out the screen and one of the swiss cheese baffles from the muffler. Remove the cylinder base gasket and just use gasket maker (only two screws hold on the cylinder and in almost all cases the screws were loose to really loose). Retune the carb, and the saw really cuts well. I have run 16" bars on these saws fully buried in Doug Fir with no sign of bogging down the saw.:biggrinbounce2:

Mike

I just bought a near mint 2300av with the hope that I could mod the muffler and turn it into a good cutter. Any way you could send a pic of what you mean by removing cylinder base gasket? I haven't looked in the muffler yet but the only mod i've done is drilling bigger hole and griding slits in the side. Not at all familiar with what you mean by removing cylinder gasket.. is it something i have to do to get to the baffle?

 

[Rio95]

No, removing the base gasket means taking the cylinder off the crankcase and replacing the gasket seal there with an instant gasket, effectively lowering the cylinder slightly. It is nothing to do with the muffler mod, it is a whole mod on its own.
I would not recommend it if you are not comfortable with the idea of pulling your whole saw to bits.

 

[jtc16]

Gotcha, I don't think I'm ready for that yet. Maybe I'll find a broken one for $5 someday to practice on one day but for now I don't have the extra $ to pay a mechanic if I can't get it back together. Does it matter which baffle I take out?

 

[CascadeHusky]

I just bought a near mint 2300av with the hope that I could mod the muffler and turn it into a good cutter. Any way you could send a pic of what you mean by removing cylinder base gasket? I haven't looked in the muffler yet but the only mod i've done is drilling bigger hole and griding slits in the side. Not at all familiar with what you mean by removing cylinder gasket.. is it something i have to do to get to the baffle?

And also...casey v was last seen here 9 1/2 years ago....

 

[Blisters]

I have a 3314 poulan saw that I did a lot of work to.it has been ported about 50% of the piston width on the exaust side and about 30% on intake. I removed muffler and pulled out the bolt sleeves and cut 1/4 deep and 1/2 inch long slots in em also removed screen. I took out the jug gasket. The 3314 is a 42 cc saw so it cut good to start with, but that thing is a beast now mods make a world of difference.

 

[jtc16]

And also...casey v was last seen here 9 1/2 years ago....

Oh i see..

Well about the only thing I am knowledgeable enough to do is slight muffler modding. I have a Craftsman 3.7 61cc that is supposedly the same saw as a Poulan 3800 61cc and I did some drilling and grinding to the muffler and re-tuned and it is a lot stronger. For this 2300 I am just going to mess around with different muffler configurations until I think it is good, it has 2 baffles so one I've already drilled and took the other and the screen out, re-tuned and it seems a little stronger but not much. Now I'm going to try with just the drilled baffle and screen out and try it. I've heard if the muffler is too open you'll lose power ? Anyway, even though the 2300 is a 38cc it came with an 18" bar so I'm betting even with the muffler mod if I want enough power for say a 14" limb I better go down to a 14" bar

 

[jtc16]

I took out the jug gasket.

What's a jug gasket?