Opening up a muffler? Is it even a good idea?

[fields_mj]

Your experience is different from mine. For me, the ear muffs are much quieter than the plugs. Another difference: I do not want to be contacted by anyone when I am operating machinery, so I have no need or desire for Bluetooth.

I'm curious what the rating is on your ear muffs. Honestly, its more about comfort and functionality than it is the NRR rating. I'm just curious what you're using because I'm always up for trying something better.

As far as BT goes, I don't WANT to be contacted while I'm running equipment, but that's not the point. After +20 years, she finally understands that when I'm operating equipment, a phone call means someone is being rushed to the ER, and I'll take a look at her text message(s) when I get a chance which may not be for a while. It has proven to be a healthy compromise.

 

[Hermio]

I'm curious what the rating is on your ear muffs. Honestly, its more about comfort and functionality than it is the NRR rating. I'm just curious what you're using because I'm always up for trying something better.

As far as BT goes, I don't WANT to be contacted while I'm running equipment, but that's not the point. After +20 years, she finally understands that when I'm operating equipment, a phone call means someone is being rushed to the ER, and I'll take a look at her text message(s) when I get a chance which may not be for a while. It has proven to be a healthy compromise.

I have not checked recently, but I believe my muffs are around 30-32 dB reduction. Good point on the ER message. But when I am using the chainsaw, I am more likely to be the one who needs a trip to the ER. I keep my phone with me.

 

[fields_mj]

I have not checked recently, but I believe my muffs are around 30-32 dB reduction. Good point on the ER message. But when I am using the chainsaw, I am more likely to be the one who needs a trip to the ER. I keep my phone with me.

We've had LOTS of "discussions" over the past 20 years about why I don't answer phone calls or respond to texts while I'm trying to get work done. The truth is that I don't hear the phone ring or feel it vibrate, and I'm focused on what I'm doing. It just never crosses my mind to stop and check my phone. Of course her comment has always been "What if there's an emergency?" I never say it, but my thought has always been exactly what you said in that the odds are that I'M the one that would likely be having the emergency. Realistically, she feels ignored and I get that. When I started using bluetooth, I had a serious conversation with her about calling me while I'm out working with equipment. Basically, I told her that calling because she can't figure out what to fix for dinner and she's running out of time does NOT qualify as an emergency. If a family member is being rushed to the ER, THAT'S the kind of emergency she can call about. Even then I probably won't be able to answer in time, BUT I'll shut the equipment down ASAP and call right back. If that was going to be an issue, I'd go back to regular plugs/muffs. I also told her that texting was fine, but none of this crap where she blows up my phone because its distracting and therefore dangerous. Fit it all into 1 text. I'll here it, but I'm not stopping to respond. When the saw runs out of fuel, or I need to stop and clean the screen off the radiator on the tractor, or when I've finished welding/grinding, basically the next time I stop for a drink of water, I'll dig my phone out of my pocket (not always easy depending on what I'm wearing) and I'll send a single, very brief response before I get back to work. Then she knows I'm not dead, and she gets her question answered, even if the answer is "I don't know." Thus far it has worked out well.

Anyway, back to muffler mods. Yeah, they are loud but if you're not already wearing ear pro, you're going deaf regardless of whether you're running a 35cc saw stock, or you're running a 100cc saw with a bark box.

 

[Hermio]

We've had LOTS of "discussions" over the past 20 years about why I don't answer phone calls or respond to texts while I'm trying to get work done. The truth is that I don't hear the phone ring or feel it vibrate, and I'm focused on what I'm doing. It just never crosses my mind to stop and check my phone. Of course her comment has always been "What if there's an emergency?" I never say it, but my thought has always been exactly what you said in that the odds are that I'M the one that would likely be having the emergency. Realistically, she feels ignored and I get that. When I started using bluetooth, I had a serious conversation with her about calling me while I'm out working with equipment. Basically, I told her that calling because she can't figure out what to fix for dinner and she's running out of time does NOT qualify as an emergency. If a family member is being rushed to the ER, THAT'S the kind of emergency she can call about. Even then I probably won't be able to answer in time, BUT I'll shut the equipment down ASAP and call right back. If that was going to be an issue, I'd go back to regular plugs/muffs. I also told her that texting was fine, but none of this crap where she blows up my phone because its distracting and therefore dangerous. Fit it all into 1 text. I'll here it, but I'm not stopping to respond. When the saw runs out of fuel, or I need to stop and clean the screen off the radiator on the tractor, or when I've finished welding/grinding, basically the next time I stop for a drink of water, I'll dig my phone out of my pocket (not always easy depending on what I'm wearing) and I'll send a single, very brief response before I get back to work. Then she knows I'm not dead, and she gets her question answered, even if the answer is "I don't know." Thus far it has worked out well.

Anyway, back to muffler mods. Yeah, they are loud but if you're not already wearing ear pro, you're going deaf regardless of whether you're running a 35cc saw stock, or you're running a 100cc saw with a bark box.

Off topic a bit, but I saw a video where someone compared the 500i with stock muffler vs Bark Box. The stock muffler actually cut faster!

 

[scottr]

So, the OP asked multiple GOOD questions that nobody has really addressed. Before he goes and messes up his brush cutter, he wants to know what the effect SHOULD be. My non-technical opinion is that if the exhaust is too restrictive, you loose power, mostly at the higher end of the RPM range because at the lower end, because you're not dumping as many CCs of exhaust per second at low RPMs . At the higher RPS, when the engine is under a load, a restrictive exhaust keeps the exhaust gasses from exiting the combustion chamber. This means that some of your CCs are not available to fill with fresh fuel and air which robs the engine of both torque and HP.

Here's what I did. I ordered a new hotzfforma brush cutter for the purpose of beating the crap out of it running a 9" Forster brush blade to cut invasive honeysuckle. When I installed the 9" blade, it was noticeably sluggish. With a string head, it would have been fine, and I expect the heavy 9" brush blade to take a little time to get up to speed, but I was really wanting better throttle response in the woods. Looking at the exhaust, it basically had the same setup you have as far as a single 10mm pipe through the cover. I poked another 3/8 hole in it and its not NEARLY as sluggish as it was before. It might be just as sluggish as it originally was when you first hit the trigger, but it does get up to speed a LOT faster. I never actually used the blade on anything before I modified the exhaust, but I expect that it also maintains the RPM a lot better when its in use. If your using your machine to run a heavy blade, and it seems like it struggles to get up to speed more than it should, I'd say that opening up the exhaust is the first step. If you mess up, you can always cover the hole with a piece of sheet metal and a screw or steel pop-rivet.

The other thing I'd look at is the little cover on the outside to make sure that it only redirects the exhaust, and doesn't restrict it any.

Oh, and I wouldn't put anymore RTV no the cover when you bolt it back on again

So, the OP asked multiple GOOD questions that nobody has really addressed. Before he goes and messes up his brush cutter, he wants to know what the effect SHOULD be. My non-technical opinion is that if the exhaust is too restrictive, you loose power, mostly at the higher end of the RPM range because at the lower end, because you're not dumping as many CCs of exhaust per second at low RPMs . At the higher RPS, when the engine is under a load, a restrictive exhaust keeps the exhaust gasses from exiting the combustion chamber. This means that some of your CCs are not available to fill with fresh fuel and air which robs the engine of both torque and HP.

Here's what I did. I ordered a new hotzfforma brush cutter for the purpose of beating the crap out of it running a 9" Forster brush blade to cut invasive honeysuckle. When I installed the 9" blade, it was noticeably sluggish. With a string head, it would have been fine, and I expect the heavy 9" brush blade to take a little time to get up to speed, but I was really wanting better throttle response in the woods. Looking at the exhaust, it basically had the same setup you have as far as a single 10mm pipe through the cover. I poked another 3/8 hole in it and its not NEARLY as sluggish as it was before. It might be just as sluggish as it originally was when you first hit the trigger, but it does get up to speed a LOT faster. I never actually used the blade on anything before I modified the exhaust, but I expect that it also maintains the RPM a lot better when its in use. If your using your machine to run a heavy blade, and it seems like it struggles to get up to speed more than it should, I'd say that opening up the exhaust is the first step. If you mess up, you can always cover the hole with a piece of sheet metal and a screw or steel pop-rivet.

The other thing I'd look at is the little cover on the outside to make sure that it only redirects the exhaust, and doesn't restrict it any.

Oh, and I wouldn't put anymore RTV no the cover when you bolt it back on again

Hello fields_mj , did you calculate the area of the pipe and the area of the exhaust hood (little cover on the outside) ?

 

[Sidecarflip]

I use them on my tractor. But they are not enough when running a chainsaw. Earplugs realistically reduce noise by 10-15 dB. Most over-the-ear muffs reduce it by about 30 dB.

I don't have to on any of my tractors 2 have cabs and the one open station is turbocharged (like the others are) and they all have mufflers too. Quiet as mice. I could actually remove the mufflers because the turbo chargers are mufflers in themselves.

 

[DennisCA]

Not at all. Competition sawyers all have expansion chambers on their competition saws, your issue is, one you lack the mathematical knowledge to extrapolate the dimensions required to fabricate one and secondly, you lack the fabrication skills to produce one anyway and that is obvious by your comment. You won't find what is required on Goggle, or any common search engine anyway. Stick with a stock muffler as an expansion chamber is beyond your realm of making.

Thank you I forgot why I stopped coming here last time.

 

[Hermio]

I don't have to on any of my tractors 2 have cabs and the one open station is turbocharged (like the others are) and they all have mufflers too. Quiet as mice. I could actually remove the mufflers because the turbo chargers are mufflers in themselves.

I wish I had a cab and a FOPS structure!

 

[StihlsawuserMS361]

My audiologist tells me that as good as ear plugs are, muffs are better. Somehow the noise still goes into the ear around the outside of the ear itself into the ear canal.
Her suggestion is to wear both. But in doing so, you don't get double insulation. It's more like the highest number, added to one half of the lower one.
Example...my inside plugs give me 32 db reduction, over the head muffs 27, which will equal about 46 db total deduction. I always wear both when using the chainsaw and tractors, if it's for any length of time. Try to save what's left.
Your mileage may vary of course

 

[Sidecarflip]

At my age (74) auditory loss is very common anyway. Why I have hearing aid's and ones prescribed by the professional audiologist at the hospital's audio department I go to and not some over the counter ones you can buy and play with either. Mine are Sonax and have a Blue Tooth app on my phone to control them. My total cost on them was 50 bucks, my BC/BS and Medicare paid the rest. I believe the retail cost was around 4 grand.

 

[Lionsfan]

I don't have to on any of my tractors 2 have cabs and the one open station is turbocharged (like the others are) and they all have mufflers too. Quiet as mice. I could actually remove the mufflers because the turbo chargers are mufflers in themselves.

I usually stay out of these type posts, but a turbo is no sort of muffler in any way whatsoever.

 

[Hermio]

My audiologist tells me that as good as ear plugs are, muffs are better. Somehow the noise still goes into the ear around the outside of the ear itself into the ear canal.
Her suggestion is to wear both. But in doing so, you don't get double insulation. It's more like the highest number, added to one half of the lower one.
Example...my inside plugs give me 32 db reduction, over the head muffs 27, which will equal about 46 db total deduction. I always wear both when using the chainsaw and tractors, if it's for any length of time. Try to save what's left.
Your mileage may vary of course

I think the reduction rating or earplugs is overstated. If they are shoved firmly in, maybe they meet the claims. But in my experience, they tend to creep out, losing their effectiveness until you push them in again. Though my saw is Stihl, my helmet is Husqvarna, and its muffs do a very good job.

 

[Hermio]

I usually stay out of these type posts, but a turbo is no sort of muffler in any way whatsoever.

Yeah. But it whistles while you work!

 

[Sidecarflip]

I usually stay out of these type posts, but a turbo is no sort of muffler in any way whatsoever.

It certainly is because in operation it breaks up the sound waves. I take it you have never read what is stamped on the turbo casting of all Vo-Mack trucks. It's cast right into the outer scroll casting that it is A MUFFLER. However it won't muffle the sound of an exhaust engine brake aka: Jake Brake for the uninformed.

I retired after working as a tech at a Class 8 heavy truck dealership plus I toted their oversize machinery around not only for them but their parent company and when I retired, I bought the tractor I used, a long nose Western Star with a double bunk on it and an 18 speed Roadranger. 27 years worth and I also bought a 38 foot Timpte hopper bottom grain trailer to deliver my grain (and other's) to the local elevator in Toledo. I own 2 Snap On roll around tool boxes full of tools as well.. Always got a nice tool allowance from them. While not germane, I tossed that in there anyway. I've looked at more turbo's than you'll ever see and replaced a lot as well because when a diesel engine has overhead issues and drops a valve or ring issue, it always goes out through the turbo and lunches the hot side, necessitating a new turbo, among other issues as well.

Finally, I like the sound of a turbo spooling up, especially one with no muffler. Only reason I don't replace them on any of my turbo charged tractors is the mufflers are fine and I'm not wasting money replacing something that is shot.

That don't apply to my diesel pickup truck however. The muffler and soot trap got replace with a 4-6" stainless straight pipe years ago and she sounds SWEET even at an idle now and I bought straight lengths of 304 stainless and formed the bend right here in the shop and of course TIG welded them together using the proper internal purge gas to prevent 'sugaring' the inside diameters. I am a AWS certified TIG welder as well. I'd like to get my Nuclear cert as well, before I die.

Some turbo's muffle better than others, all depends on how the hot side turbo vanes are arranged actually but they all provide some degree of muffling so you are dead wrong and off base with your comment. My suggestion is for you to research in depth before making pronouncements that have little to no bearing on your comment. Vo-Mack and Mack before them has been casting that in their turbo housing about forever.

I remember it was there back in the early 60's on their ill fated inline 6 motors and even on their V8's that I wish I had one actually. In the early 60's I drove a Mack Superliner conventional with a 350 V8 and it only had a 7 speed in it with Camel Back suspension. When you popped the hood to check the fluids, the cylinder banks hung out over the frame rails. Only bad thing was the turbo nestled in the Vee between the cylinder banks, right in front of the cowl in front of the windshield so it was a hot truck to drive and it had no AC or power steering either. Strictly Armstrong steering and of course it had the signature green Mach interior paint and the horrible vinyl dash covering.

Straight piped from the factory btw. Single 6" and it was a smoker after the shop removed the 'puff limiter'.

The Western Star I own also has twin 6" straights and it's turned up the max that CAT allows by of course, factory trained technicians. It's a 3406B model NZ engine FYI. 450 to the ground in 18 direct and it too smokes, just the way I like it. It's a 100+ capable truck. The old mechanically injected Cat's are easy to crank up actually, the ones with the Bosch pumps that is. I don't fool with that anyway and I have the Western Star dealership do all my services as well.

Easy to tell if any road tractor is a 100+ MPH unit by just looking at the speedometer and not trying to decipher the builders plate attached to the door jamb... if the clock goes to 80, it's a dog. If the clock goes to 100 it's not. I can peg mine in 17th direct btw. I've did it before and with a trailer out back too. I figure red line is around 120 as the speedo only goes to 100. It sounds SWEET as well...

 

[Sidecarflip]

I may not know a helluva lot about saws like porting them for instance but I DO KNOW about diesels and big trucks have spun wrenches and drove them all the years I worked. In fact my old boss and division manager as well as the shop service writer and technician boss are good friends of mine and I hunt with them both even now. We have hunted everywhere but Africa and that is on our to do bucket list.

Was a great job, with fantastic pay and fantastic benefits too. Because I was personal friends with the division manager he always took 'care' of me but I was told to keep my mouth shut and I did. I even got to fly on the company Lear and my service manager was the designated pilot on it and the twin engine Beech Bonanza so I always rode in the co-pilot's seat. If we were going to fly somewhere, I was always excused from work ahead of time (still got paid) and got to have fun in faraway places too.

Only time I could concealed carry and not have an issue and I did, always. Always took my Kimber full size or my 2 shot derringer along. One never know when they might be needed The company owned an offshore yacht a custom built Rybiki 60 foot in Marathon Florida so I got to go on offshore fishing trips as well. I don't fish so I played bartender. One for me and 4 for them.... It had a full time crew and there was always plenty of scantily clad young girls too ( that I won't get into on here)... The company owned it's own private airport as well. So no traffic issues on taking off and they had a private runway in Marathon as well.

I remember one time we flew to Louisville for the truck show and we parked in front of a Gulfstream and I commented to the old man why we didn't have one of those (lots bigger and just as fast as the Lear) and his comment was cost to which I replied, only a couple million more... In commercial airspace, only the military can exceed the speed of sound. Commercial and private aircraft cannot so Tom had to maintain below 500 mph and adjust that constantly (well the auto pilot did actually), not him but you could fly within 5 mph of the sound barrier, which he did all the time, and the max ceiling was 50K feet and at 50, the turbo jet engines were working real hard to maintain air speed. Least the old man wasn't into cars, he was into pretty gals however and his wife ignored it all. I guess so long as the bacon came in and her allowance was unlimited, she didn't care. Amazing views up there too. I will always remember the curvature of the earth and on a clear day you could see both Toledo and Cleveland if you looked out the right windows. Fun days, fun times and now retirement and owning and managing a machine and fab shop and farming for a loss... and dealing with inoperable cancer.

 

[Lionsfan]

It certainly is because in operation it breaks up the sound waves. I take it you have never read what is stamped on the turbo casting of all Vo-Mack trucks. It's cast right into the outer scroll casting that it is A MUFFLER. However it won't muffle the sound of an exhaust engine brake aka: Jake Brake for the uninformed.

I retired after working as a tech at a Class 8 heavy truck dealership plus I toted their oversize machinery around not only for them but their parent company and when I retired, I bought the tractor I used, a long nose Western Star with a double bunk on it and an 18 speed Roadranger. 27 years worth and I also bought a 38 foot Timpte hopper bottom grain trailer to deliver my grain (and other's) to the local elevator in Toledo. I own 2 Snap On roll around tool boxes full of tools as well.. Always got a nice tool allowance from them. While not germane, I tossed that in there anyway. I've looked at more turbo's than you'll ever see and replaced a lot as well because when a diesel engine has overhead issues and drops a valve or ring issue, it always goes out through the turbo and lunches the hot side, necessitating a new turbo, among other issues as well.

Finally, I like the sound of a turbo spooling up, especially one with no muffler. Only reason I don't replace them on any of my turbo charged tractors is the mufflers are fine and I'm not wasting money replacing something that is shot.

That don't apply to my diesel pickup truck however. The muffler and soot trap got replace with a 4-6" stainless straight pipe years ago and she sounds SWEET even at an idle now and I bought straight lengths of 304 stainless and formed the bend right here in the shop and of course TIG welded them together using the proper internal purge gas to prevent 'sugaring' the inside diameters. I am a AWS certified TIG welder as well. I'd like to get my Nuclear cert as well, before I die.

Some turbo's muffle better than others, all depends on how the hot side turbo vanes are arranged actually but they all provide some degree of muffling so you are dead wrong and off base with your comment. My suggestion is for you to research in depth before making pronouncements that have little to no bearing on your comment. Vo-Mack and Mack before them has been casting that in their turbo housing about forever.

I remember it was there back in the early 60's on their ill fated inline 6 motors and even on their V8's that I wish I had one actually. In the early 60's I drove a Mack Superliner conventional with a 350 V8 and it only had a 7 speed in it with Camel Back suspension. When you popped the hood to check the fluids, the cylinder banks hung out over the frame rails. Only bad thing was the turbo nestled in the Vee between the cylinder banks, right in front of the cowl in front of the windshield so it was a hot truck to drive and it had no AC or power steering either. Strictly Armstrong steering and of course it had the signature green Mach interior paint and the horrible vinyl dash covering.

Straight piped from the factory btw. Single 6" and it was a smoker after the shop removed the 'puff limiter'.

The Western Star I own also has twin 6" straights and it's turned up the max that CAT allows by of course, factory trained technicians. It's a 3406B model NZ engine FYI. 450 to the ground in 18 direct and it too smokes, just the way I like it. It's a 100+ capable truck. The old mechanically injected Cat's are easy to crank up actually, the ones with the Bosch pumps that is. I don't fool with that anyway and I have the Western Star dealership do all my services as well.

Easy to tell if any road tractor is a 100+ MPH unit by just looking at the speedometer and not trying to decipher the builders plate attached to the door jamb... if the clock goes to 80, it's a dog. If the clock goes to 100 it's not. I can peg mine in 17th direct btw. I've did it before and with a trailer out back too. I figure red line is around 120 as the speedo only goes to 100. It sounds SWEET as well...

With all due respect. you're full of hot air, and you should quit while you're ahead. Turbo's are not mufflers, and have nothing to do with noise level in any application.

 

[J.Noss]

With all due respect. you're full of hot air, and you should quit while you're ahead. Turbo's are not mufflers, and have nothing to do with noise level in any application.

While that's not the turbocharger's intended purpose, the exhaust gases do pass through them and because of that it's not to hard to understand how/why the turbo would in effect lower the S.P.L. produced by the engine.

 

[Lionsfan]

While that's not the turbocharger's intended purpose, the exhaust gases do pass through them and because of that it's not to hard to understand how/why the turbo would in effect lower the S.P.L. produced by the engine.

Disagree, it don't muffle squat.

 

[Sidecarflip]

Disagree, it don't muffle squat.

Opinions are like azzholes, everyone has one, some stink, some don't. In this case yours stinks. Whatever you say you believe I guess even though the proof is right in front of your nose if you care to look that is and obviously you don't. Bet you are a Biden fan too.

I'm done with you. Have a nice day.

 

[Lionsfan]

Opinions are like azzholes, everyone has one, some stink, some don't. In this case yours stinks. Whatever you say you believe I guess even though the proof is right in front of your nose if you care to look that is and obviously you don't. Bet you are a Biden fan too.

I'm done with you. Have a nice day.

Once again, you don't know squat, whether it be turbos, muffler mods or my political leanings.