Question about 'dual port' mufflers

[pgg]

Just curious, looking thru these forums, seems dual port design mufflers are all the rage to get some extra 'kick' from your chainsaw. Now, just wondering, is there any difference, power-wise, between a dual port with the stubby twin protruding pipes - and a common 'drill-job' ?? (drill-job meaning two or three extra exhaust holes simply drilled thru the 'normal' muffler face) Any REAL difference between either?? I assume the shop brought dual port mufflers are also actually restricted somewhat with baffles inside also? Or is the difference between a 'drill-job' and dual port basically just cosmetic, ie the twin outlet pipes simply LOOK better but really perform no different than the 'drill-job'??

 

[rahtreelimbs]

The only advantage.............other than looks..............that the pipes give is controlled direction of the exhaust gas!!!


If you are OK with a "drill job" have at it!!!


Just be sure to thoroughly deburr and clean the muffler!!!


Also, depending on where you are using the saw a screen may be needed!!!

 

[pgg]

From rah,

"The only advantage.............other than looks..............that the pipes give is controlled direction of the exhaust gas!!!"


Thanks rah, yeah I didn't think there'd be any real difference. Actually all my chainsaw mufflers cop a 'screen removal & drill-job' from brand-new

 

[2000ssm6]

What kinda of saw ya got? The ms440/044, 460/046, 660/066 all have a factory dual port you can get from the dealer....I have one of my 440 and it woke it up alot. Search for "muffler mod" and you will have weeks of reading .Remember to adjust the carb after the "mod".

 

[drunkenredneck]

There can be some differences in performance between the two. Most of the time they are very minimal though. One can have more back pressure than the other which can be a negative or a positive. I would like to add though that it is better to have the ports in different places on the muffler. I know this seems wierd but think of yourself as the exhaust gasses inside the muffler that have just been spent out of the exhaust port. Ok so if say there is one hole directly in the middle of the muffler that is 1 1/2" large all of the gasses on the sides of the muffler are intercepting the gasses that have come straight out of the port this causes turbulence which will slow the outlet of the gasses. Now say you take the same muffler and you are still the same gasses. Put one half inch hole in the center front cover of the muffler, one half inch hole in the left side of the muffler and another in the right side. Same overall diameter of exhaust outlet. But now you have three differnt spots where the gas can escape. The gasses that have expanded to fill the sides of the muffler will go out there own respective sides and the gas that shot straight out of the exhaust port will go out the front cover. Now you have much less turbulence from them bouncing together and trying to get out the same whole. It will in turn flow better and smoother. Think about it kinda like a cafeteria at a school. If theres only one lunch line there will be a bunch of people crowding and bottlenecking to fight for position but add another line on the opposite side of the food and it will flow smoother with less imperfections and go alot faster. I'll stop confusing you now.

 

[pgg]

Thanks for the info drn, maybe I'm doing something right after all, here's how I did the two saws I'm running at the moment(husky 335 & stihl 036, rough and ready I admit, but definite kick in performance

 

[Tzed250]

Watch for burning bark!

 

[drunkenredneck]

Yea thats good placement but like what was already said I'd put a screen in them if I cut over twenty feet away from a water source.

 

[OilHead]

Neither of my 2 Walkerized muffler mod saws have screens.The problem with drilling holes & not putting screens over them is when transporting them in the back of the pickup crap is blowing all around & a piece of sand could ingest itself in thru the muffler and up into the cylinder which without saying would wreck your saw.. At liest with the pipes a person could put a couple wine corks or those plastic injector type wine bottle stops into the dual pipes after the muffler has cooled off enough for transport. So its up to you weather you want to take the chance with the drill job that looks well hacked like a bad abortion or send it off to someone who has the jig allready setup to do a clean job.

 

[Tree Sling'r]

Neither of my 2 Walkerized muffler mod saws have screens.The problem with drilling holes & not putting screens over them is when transporting them in the back of the pickup crap is blowing all around & a piece of sand could ingest itself in thru the muffler and up into the cylinder which without saying would wreck your saw.. At liest with the pipes a person could put a couple wine corks or those plastic injector type wine bottle stops into the dual pipes after the muffler has cooled off enough for transport. So its up to you weather you want to take the chance with the drill job that looks well hacked like a bad abortion or send it off to someone who has the jig allready setup to do a clean job.

You can still put sceeens in. All my modded mufflers have screens.

 

[terrafirma]

Does anyone modify the 046/460 Dual Port even further? Or is it basically good as it gets?

 

[Frank Boyer]

There can be some differences in performance between the two. Most of the time they are very minimal though. One can have more back pressure than the other which can be a negative or a positive. I would like to add though that it is better to have the ports in different places on the muffler. I know this seems wierd but think of yourself as the exhaust gasses inside the muffler that have just been spent out of the exhaust port. Ok so if say there is one hole directly in the middle of the muffler that is 1 1/2" large all of the gasses on the sides of the muffler are intercepting the gasses that have come straight out of the port this causes turbulence which will slow the outlet of the gasses. Now say you take the same muffler and you are still the same gasses. Put one half inch hole in the center front cover of the muffler, one half inch hole in the left side of the muffler and another in the right side. Same overall diameter of exhaust outlet. But now you have three differnt spots where the gas can escape. The gasses that have expanded to fill the sides of the muffler will go out there own respective sides and the gas that shot straight out of the exhaust port will go out the front cover. Now you have much less turbulence from them bouncing together and trying to get out the same whole. It will in turn flow better and smoother. Think about it kinda like a cafeteria at a school. If theres only one lunch line there will be a bunch of people crowding and bottlenecking to fight for position but add another line on the opposite side of the food and it will flow smoother with less imperfections and go alot faster. I'll stop confusing you now.

I am not sure that three 1/2" holes equal the area of one 1 1/2" hole.

 

[flashy]

why modify?

I choose to trust the engineers and testers who design and build these complex machines. If you want more power and performance, buy a bigger saw. I would be willing to bet that most of these guys who modify have ruined, either quickly or over the course of a few months, some very well designed saws. I doubt that any are willing to admit it, though.
I do understand the idea of trading longevity for performance, if you are a professional saw user. New saws ARE deductible.

 

[Cut4fun]

Does anyone modify the 046/460 Dual Port even further? Or is it basically good as it gets?

There is the stihl DP muffler cover you can open yourself and there is the Wojo Modded covers sold by the site sponsor.
If it is a stock saw I dont see what you would be gaining over a stock DP cover modding the cover.

 

[Crofter]

I choose to trust the engineers and testers who design and build these complex machines. If you want more power and performance, buy a bigger saw. I would be willing to bet that most of these guys who modify have ruined, either quickly or over the course of a few months, some very well designed saws. I doubt that any are willing to admit it, though.
I do understand the idea of trading longevity for performance, if you are a professional saw user. New saws ARE deductible.

Using the new saw "as is" certainly is a choice that a lot of people make.

I think you would lose money on your bet though to say MOST: only a few who have barged ahead or taken bad advice have ruined their saws!
Simply enlarging the exhaust outlet (providing the carburetor is adjustable and is reajusted!) gives most new EPA saws about 20 - 25% more power with no apparent tradeoffs other than decidedly more noise. Cheaper and pounds lighter than the bigger saw choice.
Stick around and keep your mind open!

 

[ScottWojo]

I choose to trust the engineers and testers who design and build these complex machines. If you want more power and performance, buy a bigger saw. I would be willing to bet that most of these guys who modify have ruined, either quickly or over the course of a few months, some very well designed saws. I doubt that any are willing to admit it, though.
I do understand the idea of trading longevity for performance, if you are a professional saw user. New saws ARE deductible.

Flashy,

There are several concepts that you are missing here.
First off the reason that current saws are limited in performance is not because of the engineers. It is a direct result of the EPA. They want you running extremely hot ehaust temps and very low oil mixture to ensure there are no unburned hydrocarbons being emitted from the saw into the atmosphere. The way to do this is by restricting the exhaust. This also lowers your HP, and makes the engine extremely vulnerable to dirty filters, improper mixed fuel, or faulty carbs. Any thing that causes the least little increase in heat will destroy the piston and cylinder.

I would admit to you if I believed that doing modifications would decrease the life of a saw. I assure you it only lengthens its life. Here I am speaking of the woods port typical modification and not racing applications.
The other concept you are missing is getting extremely more power from a lighter saw. Although impossible, imagine that you could obtain the same power that an 066 has in the small compact package of an 026. You could work longer with less fatigue at the end of the day. While you can not get that kind of result from an 026, you can significantly modify that engine so that it could run with the stock 036's. And modify the 036 so that it will run with the stock 460's.
Getting more power and cooler operating temps is what the muffler modification is all about.

With Great Esteem,
Scott

 

[troutfisher]

I choose to trust the engineers and testers who design and build these complex machines. If you want more power and performance, buy a bigger saw.

BWAHAHAHAHAHAHAHAHAHAHA

 

[Cut4fun]

BWAHAHAHAHAHAHAHAHAHAHA

I just didnt feel like toying with another one. Thanks for for me today.

 

[aquan8tor]

I am not sure that three 1/2" holes equal the area of one 1 1/2" hole.

area of a circle= 3.14x (radius of circle squared)


3.14 x ( .25 x .25 ) = .19625 sq. inches per 1/2" hole. x3= .58875 sq. inches


3.14 x (.75 x .75) = 1.76625 sq. inches per 1 1/2" hole. You'd need NINE 1/2" diameter holes to equal the area in square inches of ONE 1 1/2" hole. Whether or not multiple small diameter holes lets pressure out faster than one single hole, I do not know.

 

[flashy]

Flashy,

There are several concepts that you are missing here.
First off the reason that current saws are limited in performance is not because of the engineers. It is a direct result of the EPA. They want you running extremely hot ehaust temps and very low oil mixture to ensure there are no unburned hydrocarbons being emitted from the saw into the atmosphere. The way to do this is by restricting the exhaust. This also lowers your HP, and makes the engine extremely vulnerable to dirty filters, improper mixed fuel, or faulty carbs. Any thing that causes the least little increase in heat will destroy the piston and cylinder.

I would admit to you if I believed that doing modifications would decrease the life of a saw. I assure you it only lengthens its life. Here I am speaking of the woods port typical modification and not racing applications.
The other concept you are missing is getting extremely more power from a lighter saw. Although impossible, imagine that you could obtain the same power that an 066 has in the small compact package of an 026. You could work longer with less fatigue at the end of the day. While you can not get that kind of result from an 026, you can significantly modify that engine so that it could run with the stock 036's. And modify the 036 so that it will run with the stock 460's.
Getting more power and cooler operating temps is what the muffler modification is all about.

With Great Esteem,
Scott

Thanks for the good info. I understand your points perfectly, but I can't help but wonder---- If the engineers know that the power output will be less, would they not design down the saw components in an effort to reduce cost and weight?
Also, I should have KNOWN the government is the reason for this mess. Thats exactly why we should not nationalize healthcare.
I asked both of the saw dealers that I do business with about muffler mods, and they both highly discourage it.