Homelite410
Hack with a CNC Mill
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That is where factory opening was. Those are 1" od pipes.
Let's Start a Muff Mod Thread
- Thread starter Ironworker
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1375619cm3
ArboristSite Operative
Has anyone muff mod a jonsered 2171. And was there a notice able power differance?
Heilman181
ArboristSite Operative
Hummmmmm........
Homelite, do you think TWO 1" pipes would be too big on my 359? I was going to do two 5/8" pipes and weld solid the OEM exhaust opening to avoid top cover burn. Maybe I should use 1" instead.
Is this something that is even going to make a performance difference and/or much of a sound difference?
adventurebob
monkeys and shakespeare, baby!
Ok, so being the OCD skeptic I am, the results of muffler mods all seem to be anecdotal. While I have heard some great sounding mods, the question remains: What's the proof other than the sound that they actually do anything? My experience is from the Motorcycle and Snowmobile worlds. There's a lot of "seat of the pants dynos" but when you actually throw some stuff on a no kidding dyno, there's no gain and in some cases there's even a loss of performance. From what I know about building two stroke exhausts there's a lot of physics and math involved that have been boiled down to things that work and things that don't. Simply drilling a hole or punching fins in the can that exists doesn't seem to follow the published knowledge of gaining power from a two stroke. Someone please explain...
A.E. Metal Werx
Addicted to ArboristSite
Your thinking more of a tuned exhaust, pipe and stinger set up. It takes a lot more smarts to improve a tuned exhaust system, as for a chainsaw set up. It's all about meeting EPA. So what ever they have to do to meet the EPA spec they will and performance always is the one to suffer. I have yet to see a modern saw not benefit from a muffler mod, the new auto tunes really gain from a muffler mod. There are tons of videos out there should real gain results from just a muffler mod.
Heilman181
ArboristSite Operative
A muffler mod ALONE might not do much at all. However, considering the two stroke engine is basically an air pump you are able to move more air in/out which allows you to add more fuel. More air + more fuel = more power. Power gains might only be minimal at 5-10%, but then you get into porting and improving the flow to make the pump work faster and more efficient to see more power gains in the 15+% range.
I don't think there is much math involved until you get into race saws with expansion chambers built into the pipes.
adventurebob
monkeys and shakespeare, baby!
Again, have watched and enjoy a great mod video. The sound of some are amazing, but what is the objective measure of "real gains?"
I know a lot of people who bolt $500 intakes and $1300 exhausts to their cars and swear up and down that the improvements are awesome. Yet many magazines who look at things objectively throw the same combos on the same cars and get 8-10HP. Yet to listen to the owners, they bolted on 50Hp. In my experience, performance gains on ones own stuff suffers from a self serving bias. Im not saying they do nothing, but man how do you prove it? Don't you want to really, objectively know that its worth the effort? I do.
I know a lot of people who bolt $500 intakes and $1300 exhausts to their cars and swear up and down that the improvements are awesome. Yet many magazines who look at things objectively throw the same combos on the same cars and get 8-10HP. Yet to listen to the owners, they bolted on 50Hp. In my experience, performance gains on ones own stuff suffers from a self serving bias. Im not saying they do nothing, but man how do you prove it? Don't you want to really, objectively know that its worth the effort? I do.
adventurebob
monkeys and shakespeare, baby!
I understand the air pump analogy. But a 2 stroke is a pump without a valve train. To make it efficient (ie more power per CC cylinder volume), a method has to be devised to help scavenge the exhaust and pull fresh FA charge into the cylinder. That is historically done through the utilization of exhaust with regard to timing and cylinder volume. The mufflers as they come from the factory work, but with all the mods, not apparently as well they could. But to know what to do, what actually makes it better vs louder shouldn't they be tested? Objectively?
Heilman181
ArboristSite Operative
Going from taking 8 seconds to cut through that log down to 5 seconds. Why? Because it is 2014 and we like to push the envelope. For some people, the GPS tells them how to get to a destination and what time they will arrive. To me, the GPS says "this is when you will arrive, do you think you can get there faster sucker?"
Those oftentimes are the people who take them to a racetrack, leave them on the trailer and just like to rev them up. It sure sounds good though.
I used to ride dirt bikes with some "pretty boys" that would ride AROUND mud puddles and slow down for creek crossings while I blazed through everything like a raped ape. However, on the way back to the trucks, they would hit the last mud puddle hard to get the bikes all muddy. Then, they would leave them in the back of the trucks for a few days and drive around town like they actually did something.
Can you tell an 8-10 hp increase in a vehicle? I sure can't, but it makes the ego driven society sure feel better about themselves.
Heilman181
ArboristSite Operative
Correct, so the quicker you can get exhaust out of the muffler the quicker you can get fresh air/fuel in. Baffles, CAT materials that result in excessive heat and reduced air flow, etc... to suit EPA requirements are not "performance" minded.
The objective results can be checked with a stop watch. With these minor mods, you are able to run a different rpm range. In most cases, turning 25-40% more rpms. However, higher rpms is not the only or best way to achieve more power.
It all depends on what you are doing with the saw. Just a similar concept of changing the running gear ratios in a vehicle.
A.E. Metal Werx
Addicted to ArboristSite
2253 stock
2253 muffler modded
Get some larger hard wood and the times get further and further apart.
2253 muffler modded
Get some larger hard wood and the times get further and further apart.
Homelite410
Hack with a CNC Mill
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A.E. Metal Werx
Addicted to ArboristSite
Dicks tree! Sup mike? That's an old picture...!!
A.E. Metal Werx
Addicted to ArboristSite
My first 550xp muffler, has since move on to a fellow member. The 545, 550, 555, 562 are the same muffler really. The 555-562 are just a scaled up version.
One thing I would suggest is for you to buy a inexpensive after market muffler and do some experimenting with muffler mods. That way you can see for yourself.
sachsmo
Addicted to ArboristSite
Some saws don't gain a whole bunch if they were free flowing to begin with. Others are so choked up the muffler mod is at least 60% to 70% of the gain you will receive on a work ported saw.
You could port the hell out of some saws, but if the muff is stuffed you will not see the potential.
You could port the hell out of some saws, but if the muff is stuffed you will not see the potential.
ILikesEmGreen
Another crazy Poulan Fan
Dare I go there, but in some instances, a stuffed muff isn't too bad. Lol
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Homelite410
Hack with a CNC Mill
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The 359 really benefits from a muffler mod but on that one the most important thing is getting more flow thru the baffle or adding a port behind the baffle.
muffler on left is 359.
As you would. Few people can modify a tuned exhaust better than factory engineers can to see real gains. The difference is, chainsaws do not have tuned exhausts. They simply have bolt on cans. And the exit hole and exhaust gas output are heavily regulated by the EPA both for sound pressure levels and emissions. A tuned exhaust on a chainsaw, using similar timing and porting a stock two stroke motorbike has will increase power to the point the saw becomes unreliable and dangerous for woods work. We have to find the middle gounrd, and that is porting and muffler modifications.
Here's some data a member posted a few years back:
http://www.arboristsite.com/communi...d-data-temp-sound-level-and-preformance.6199/
And here is what we're talking about - a 20% improvement on Chad's Dyno with a simple factory dual port muffler mod. In other words, Stihl themselves detuned their saw to meet EPA regulations, and by simply replacing the old part modified by the factory, a 20% improvement in horse power was realized:
http://www.arboristsite.com/communi...w-vs-hd2-and-oem-vs-dual-port-muffler.240387/
Chris-PA
Where the Wild Things Are
Because a tuned pipe has such a dramatic effect on power from a 2 stroke most of the published knowledge is basically "how to make the pipe work", which makes sense. But without a pipe at all, much of the tricks and techniques are not relevant or even counter productive. Also, these are really WOT, constant (sorta) rpm engines. And then there is strato porting. It's different - get your had into it and have fun, it will be something new to learn.
