Muffler Re-Design = Extra Quiet Ideas

[KH333-HT]

I was looking to replace the rusted out muffler on my Yanmar with an over-sized auto muffler -- to make extra quiet.
This would likely have a larger diameter pipe than what’s on it now, so should have plenty of flow.
Anyone else try this?
Does anyone know if diesels are prone to back fire?
Would I need to match tail pipe diameter to intake diameter to prevent this?

==Smoke In Face Options==
Anyone have experience with tail pipes that exit beneath or toward front of tractor?
Is there more or less exhaust getting in face than if exit straight up at face level?

Thanks

 

[Aaron-HT]

I dont think diesels can backfire due to the way they are designed. I would think you will want a pretty small muffler. It seems the bigger the muffler the less likely the sound will get caught in the baffles. That is just my opinion though- I have not really tested that theory. Some of the US models had an option for an exhaust that exited under the seat.

It is my experience that the smoke will find my face no matter where I am or what direction the wind <I><s></s>was<e></e></I> blowing before I lit the fire. <E></E>

 

[KH333-HT]

Interesting theory.
I was thinking the more cavities for sound capture / absorption, the better.
The smaller mufflers I've seen have either been pretty loud OR high performance / frequency converters.

Hadn't thought about the muffler itself being under the tractor.
I was thinking keep the muffler on the side and fit it to aim the whole thing toward the ground (or wherever).

Thanks

 

[Aaron-HT]

I guess I didn't really type what I was thinking. By small muffler I meant small inlet/outlet... not the size of the actual body of the muffler.

 

[Anonymous-HT-0-HT]

I routed mine forward, down right at front of tractor, then turned out right at the bumper. Just misses my loader and hood. I did this because I mow under a lot of trees and need as low a profile as possible. Fumes don't seem to be a problem.

 

[alan-HT]

Diesels don't backfire. A tractor muffler is quite exposed, so the factory one is designed for both noise reduction and heat protection if you touch it, which is why I'd stick with factory. I routed mine forward and removed the end piece. Finally found a right-size piece with a 180-degree bend (though it was available only in stainless). Had to chop-saw a bit off, but that sent the exhaust down under and cleared everything. Onto the end I clamped a curved piece, onto that some flex pipe so if it hits something it will give.

 

[Arnold-HT]

Not sure why you think you need a muffler. On my tractor the engine males more noise than the exhaust system. My muffler is just a chamber; pretty simple. Don't add one with too many baffles, it will trap soot and restrict air flow.

 

[dal39b-HT]

I once tried to find a quieter muffler and exhaust system for my 30 hp generator. I was digging through mufflers at a local agricultural supply store and an older than I guy that worked there told me to stick with the stock muffler. His reason was simple. The combustion chamber needs to breath correctly. Exhaust systems too long and/or restrictive are easy to envision as not good for purging the exhaust from the cylinder. He said the exhaust flow through the muffler and pipes all the way to the outlet are actually matched to the engines exhaust volume, hence the "sweet spot" speed you notice in your car, or truck on the highway. Too large an area in the muffler will allow the exhaust to bounce back into the cylinder as much as a muffler too small, long, or restricted. He said he has rebuilt many cylinder heads with burned valves that had custom designed exhaust systems. I browsed a high performance muffler website when looking for a new system for my pickup and they said a lot of the same things. An improperly designed muffler system will hurt horsepower, torque and engine life. I would stick with systems listed in the parts book for your model tractor.

 

[winston-HT]

Here's my muffler routing. As I said earlier, I mow under a lot of trees and need a low profile. Not saying I never get a whiff of exhaust but not a problem.

 

[Norm-HT]

<QUOTE author="winston"><s>

</s>Here's my muffler routing. As I said earlier, I mow under a lot of trees and need a low profile. Not saying I never get a whiff of exhaust but not a problem.<e>

/e></QUOTE>

Wouldn't it have been easier to just turn the manifold forward?

 

[winston-HT]

Norm, you can't see it in the pictures but the muffler is swiveled in toward the hood a little in order to get the exhaust pipe down where I could anchor. Might could have made a little bit of a crooked connection with the clamp if I had rotated the exhaust flange forward but it would be right on top of my loader frame and needed all room available to clear hoses on loader. I definitey like your idea and next time I put my loader on I'm going to take a closer look. I might just see if it will work that way. I would like it better to get that extra bend out. Thanks for the idea.

 

[KH333-HT]

<QUOTE author="dal39b"><s>

</s>The combustion chamber needs to breath correctly. Exhaust systems too long and/or restrictive are easy to envision as not good for purging the exhaust from the cylinder. He said the exhaust flow through the muffler and pipes all the way to the outlet are actually matched to the engines exhaust volume, hence the "sweet spot" speed you notice in your car, or truck on the highway. Too large an area in the muffler will allow the exhaust to bounce back into the cylinder as much as a muffler too small, long, or restricted. He said he has rebuilt many cylinder heads with burned valves that had custom designed exhaust systems. I browsed a high performance muffler website when looking for a new system for my pickup and they said a lot of the same things. An improperly designed muffler system will hurt horsepower, torque and engine life. I would stick with systems listed in the parts book for your model tractor.<e>

/s>Not sure why you think you need a muffler. On my tractor the engine males more noise than the exhaust system. My muffler is just a chamber; pretty simple. Don't add one with too many baffles, it will trap soot and restrict air flow.<e>[/quote]/e></QUOTE>
Yes, carbon build up is an important consideration. When I pulled the old muffler off / apart, it had so much carbon buildup that I could barely see the outlet pipe perforations from the end. Tried scraping out this carbon buildup, but still looked pretty restricted. Was not that impressed with this design, so decided to try something else.

Decided to go with a long round muffler that has perforated inlet and outlet pipes parallel to each other. Perforations look to be about the same size as in the old, just more of them. Cut the manifold connecting pipe off the old muffler, and with a long 90 degree elbow (4'' radius), angled the new larger muffler down toward the front bumper.

Still have the engine knock of course, but exhaust is pretty quiet.
I'll see how it performs after other issues have been resolved.

Thanks