The mystified muffler mod

[Huskybill]

Besides the upper right side exhaust port I’m adding the lower front jungle louver exhaust port too.


I have a few 2100 mufflers with the square already for the location of the louver port.

 

[Huskybill]

Besides being a machinetool builder I’m a welder fabricator too. I understand your point I need to do intermittent welds. I can weld thin sheet metal. Turn the feed way down and do short tacs, then connect the dots. I could get a TIG machine too. Or braze, Nathan your right on the money.

I have a Hobart gas engine 200amp 100% duty cycle stick welder with a 4,000 watt generator I want to piggy back a MiG and TIG welder.

 

[Nathan Graff]

Besides being a machinetool builder I’m a welder fabricator too. I understand your point I need to do intermittent welds. I can weld thin sheet metal. Turn the feed way down and do short tacs, then connect the dots. I could get a TIG machine too. Or braze, Nathan your right on the money.

No worries then. I've just seen too many yahoos grab a Home depot, or even worse, a Horid Freight welder, and think they're going to weld thin metal, do body work, etc., and wind up blowing holes through everything. Thought I'd warn you ahead and save you disapointment if you didn't know.

I've found that self shield flux core doesn't like the repeated tack technique. Becomes a real PITA. That being said, I have an auger hopper still holding together 3 years after I did that to it, so can't be all bad.

 

[Huskybill]

Spend a few dollars more and get a better machine, I understand.

When I worked for the engineering group after a few weldments showing them what I could do they gave me an open ticket for new welding equipment, I purchased two big acorn tables and all 500 amp 100% duty cycle welding machines. They had no clue what I could really do until I set up the shop.

 

[Nathan Graff]

Fair enough. A few years ago, I got a complete setup of a ESAB 452CVCC. That's a very nice welder with 100% duty cycle at 450 amps. Welds corral panels all day without having to let the welder cool.

 

[buttercup]

Fair enough. A few years ago, I got a complete setup of a ESAB 452CVCC. That's a very nice welder with 100% duty cycle at 450 amps. Welds corral panels all day without having to let the welder cool.

I'm looking forwards to see you work sir.

 

[Nathan Graff]

Here's a feeder head gate that I built. It's 5' high. Pipe is 3.5" drill stem. Angled pieces are 1.5" square tubing.

2018-09-14_12-46-35 by wolverine00089, on Flickr

Here's a panel that I built to cover a broken screwed to post section of corral. It's 6' tall with feet. Rail spacing is 6". All of the pieces and holes were cut with a plasma cutter freehand. Pipe is 2 7/8" drill stem and the thin bars are 1" sucker rod. The rods free float in the holes.

2019-08-09_08-31-56 by wolverine00089, on Flickr

A photo of it in place. I hadn't cleaned out the old rails at that point yet. You can see the limpy steer in the right of the pic.

2019-08-09_08-32-24 by wolverine00089, on Flickr

I have a whole bunch more to build. Just racing after a ton of unfinished projects right now.

 

[buttercup]

Thanks for the pics, no doubt proper welding is your cup of coffee.

I had a beer last night and I don't even dare to look back at whatever I wrote, but since I'm not banned yet I guess it couldn't have been that bad.

Anyway I have ordered some 18mm thin walled brass tube and I will try to take some pictures and show how this can be done using silver solder. Silver solder is expensive but it can be very handy to have and know - especially for smaller things, it usually have a melting temperature at about 650C or about 1200F and it becomes a hard and strong metal.

My plan is to use 2 pieces of tube lengths that I first solder together one on top of the other before fastening them to the muffler, I will make them so that they reach from the outlet and in to about the center of the muffler (as much as possible at least).
The original port(s) will be closed, not the easiest or simplest way to do it but perhaps the most fun and cool looking.

My kit saw is in parts at the moment I want to replace the crank in it so I don't get to try it out for some time, but I did make an improvised muffler before I took it apart and it seemed to me that it had a noticeably faster spin up or acceleration without actually doing any cutting with it. I could have been fooled by the loudness though.
I do worry about the noise so if it ends up looking like more noise increase than actual grunt in the cut I will go back to the original muffler.

 

[wyk]

I find most folks overthink the muffler mod question.
It's fairly simple - mufflers vary from model to model, brand to brand. There is no one solution. Open it up until you start to see no benefits is really all one can do. Removing baffles usually helps even more. Some saws like a bit of pressure in the mufflers, others don't. I had a mildly ported 281xp that liked about 200% of the exhaust port cut out of the muffler. I also had an ms261 that simply liked it's opening massaged a bit and the baffle removed, and it acted like it was ported. All are different.

 

[buttercup]

I find most folks overthink the muffler mod question.
It's fairly simple - mufflers vary from model to model, brand to brand. There is no one solution. Open it up until you start to see no benefits is really all one can do. Removing baffles usually helps even more. Some saws like a bit of pressure in the mufflers, others don't. I had a mildly ported 281xp that liked about 200% of the exhaust port cut out of the muffler. I also had an ms261 that simply liked it's opening massaged a bit and the baffle removed, and it acted like it was ported. All are different.

That is a clearly notable performance increase.
Yes their all different with a different performance range and characteristics withing the rpm range, but I don't consider using a well proven calculation as a "guide" - to be overthinking it.
It is not an accurate physical law for every engine, but it points you in the right direction - a beacon in the night instead of pitch darkness.

 

[buttercup]

If it seems like I'm doing "too much" over this it's not because I'm dependent on my saw to have better power, it has plenty power and low end torque. It's because I'm having fun doing it.

Anyway, I found out this morning that the 18mm tube I ordered was only about 16mm inside and that don't match my goal, so I will use 3 tubes at 14,1mm inside diameter. That's going to look interesting to say the least...
Also I found an alternative to the expensive silver solder that's called "brass solder", it has a slightly higher melting point and should be suitable for both brass and steel, I will try that out as well.
There is no need for any special tools using these kinds of solder, just any cheap propane torch.

 

[buttercup]

 

[buttercup]

 

[buttercup]

This is what I came up with,

I removed the front end of the baffle box (or what it's called) to increase the flow.
The hole in the chamber dividing plate is 25mm, I have used a tea (strainer?) as a spark arestor, it has a much bigger area than the hole so it don't restrain the flow.
The patch on the main outlet port would be much easier to make as an outside patch overlapping, rather than to make an exact fill in like I did.
The outlet tubes are 14,1mm inside and together they would be 24,5mm.

I have used silver solder, the inexpensive brass solder needs too much heat for a regular torch. It still needs clean surfaces to begin with and the metal will be nearly glowing before it melts, when it does it might first just become a lump of solder.
Then you can focus on the torch flame and the solder will follow the heat, so if you want it to run in a specific direction you focus the flame just a little bit in that direction.

Finally I will sand-blow it and put some heat resistant paint on it.
The bottom outlet tube will be hidden below the frame so it's only the two upper outlet tubes that is clearly visible when mounted on the saw.

The surface area of the flow port(s) is increased about 15-16% from the stock muffler so it's actually not as dramatically as it might look, but I think the flow might be increased beyond that because of the more freely entrance in to the first chamber directly from the cylinder exhaust port. At the same time I have (hopefully) improved the silencer properties of the muffler as well, and I'm happy that I managed to add a spark arestor without making it restraining like it would be if it was just flat on to the flow port.
If I eventually consider it too loud I will go back and use a stock base muffler part with the baffle box intact, it will still have the same port area increase though it might have slightly less flow through it.

 

[Nathan Graff]

Nice job. Why did you put the spark arestor on the same side as the exhaust tubes?

 

[buttercup]

Nice job. Why did you put the spark arestor on the same side as the exhaust tubes?

Thanks!
It was just how I visualized it before I made it, it gets a little bulked towards the bottom tube but I think it's still good enough. If it was to be on the other side it would need to be moved a little bit to the center.

 

[apn73]

Lakeside Andy had figured out something similar to what the OP was talking about. I remember reading through a very long thread of his that was showing how to do a MM on a Stihl MS361, he used a pipe with a 16mm inside diameter, but that was for a stock saw. The equation was different and the pipe got larger depending on not only saw displacement, but also on the other mods you were using, such as porting. That thread disappeared after this forum crashed 5 or 6 years ago, wish I could read through it again. I haven's done that mod to my saw, but I would like to....

 

[buttercup]

Lakeside Andy had figured out something similar to what the OP was talking about. I remember reading through a very long thread of his that was showing how to do a MM on a Stihl MS361, he used a pipe with a 16mm inside diameter, but that was for a stock saw. The equation was different and the pipe got larger depending on not only saw displacement, but also on the other mods you were using, such as porting. That thread disappeared after this forum crashed 5 or 6 years ago, wish I could read through it again. I haven's done that mod to my saw, but I would like to....

That is understandable - and interesting indeed.
I have smoothed the cylinder intake and adjusted it to match the carburetor rubber manifold but nothing more than that. Changing the port timing you really need to know what you're doing if it should possibly make it better than the engineers already did.

 

[buttercup]

Lakeside Andy had figured out something similar to what the OP was talking about. I remember reading through a very long thread of his that was showing how to do a MM on a Stihl MS361, he used a pipe with a 16mm inside diameter, but that was for a stock saw. The equation was different and the pipe got larger depending on not only saw displacement, but also on the other mods you were using, such as porting. That thread disappeared after this forum crashed 5 or 6 years ago, wish I could read through it again. I haven's done that mod to my saw, but I would like to....

I would think the 361 has plenty power just as it is, but I guess the simplest and easiest way to improve it would be to add the big bore cylinder at about 65ccm. If you did a MM on it too I guess it could be at 3,7-3,8kw perhaps? Someone would call that a snappy saw.

 

[pioneerguy600]

The big bore cylinders actually produce less power than the stock cylinder piston sets do. Poor port sizes and shape, poor port timing, poor machining and most often overly high squish clearance makes big bore sets a poor choice unless one is a competent cylinder porter willing to grind the ports to a strong running setup. Out of the box the big bore sets are just mundane runners.