Project Status Update

[J_J]

Kent,

On your post about wanting to find a quieter muffler, perhaps you can try this. You probably have noticed the sound coming from different mufflers, and the young guys like loud noise, so they find an outlet tube that is really big, 3 in and larger, even into a megaphone style. What I am trying to get at is this, big pipe openings make loud noise. Years ago I saw some cars and trucks with a modified outlet pipe. The end piece was much larger than the pipe, and it had many smaller holes for the output. The frequency of the noise coming from the single opening is very loud , sort of like a straight pipe motorcycle. You can have the same amount of gases coming out the exhaust by having many smaller holes, therefore changing the frequency. I noticed this change on one of my 5 HP motors. The muffler was about 4 x 5 in, with a plate over the output that had many holes. When the center part with the holes rusted or burned out, the sound got louder and louder as the rest of the grid rusted away. Anyway, it would not take much to try, just make a clamp on outlet with many holes that is equal to the area of the single pipe.

The point of this post is about changing frequency.

 

[KentT]

Anyway, it would not take much to try, just make a clamp on outlet with many holes that is equal to the area of the single pipe.

The point of this post is about changing frequency.

JJ,

That's essentially the way this aftermarket cannister muffler is made. The holes are barely visible through the rear mesh of the PT's hood...

 

[MossRoad]

JJ,

That's essentially the way this aftermarket cannister muffler is made. The holes are barely visible through the rear mesh of the PT's hood...

Hey, that fit inside the cage? Did it help much?

 

[KentT]

Hey, that fit inside the cage? Did it help much?

Actually the cage helps hold it on -- because I couldn't thread the tailpipe to screw it on (metal was too thin), I ground some of the threads off inside the cannister muffler and forced/screwed it on. It's kind of a "wedge fit" if you know what I mean...

It deflected the wire mesh out maybe 1/4" or so -- enough to where you notice a bulge only if you look for it.

Meanwhile, I'd guess it was good for 5-7 decibels less -- noticable improvement, but still not quiet by any means. Now, it's no noiser than my Simplicities which came with a Nelson muffler, not the cheap Briggs cannisters. Before then, it was simply too loud to use for long periods without earplugs/headset. Now that I have a set of AO Worktunes (I didn't then), the noise isn't bothersome at all. My knees tire out first now, during extended work, not the noise wearing we out and making my ears ring. When I'm in Tennessee, it's not unusual for me to run it 8 hours a day, and the noise would wear me out...

 

[J_J]

Actually the cage helps hold it on -- because I couldn't thread the tailpipe to screw it on (metal was too thin), I ground some of the threads off inside the cannister muffler and forced/screwed it on. It's kind of a "wedge fit" if you know what I mean...

It deflected the wire mesh out maybe 1/4" or so -- enough to where you notice a bulge only if you look for it.

Meanwhile, I'd guess it was good for 5-7 decibels less -- noticable improvement, but still not quiet by any means. Now, it's no noiser than my Simplicities which came with a Nelson muffler, not the cheap Briggs cannisters. Before then, it was simply too loud to use for long periods without earplugs/headset. Now that I have a set of AO Worktunes (I didn't then), the noise isn't bothersome at all. My knees tire out first now, during extended work, not the noise wearing we out and making my ears ring. When I'm in Tennessee, it's not unusual for me to run it 8 hours a day, and the noise would wear me out...

On the decibel thing, if I remember correctly, a 3 db change is a 50 % change, and in your case, a reduction of sound level. I have one of those db measuring device, and it would be interesting to know the before level and after level. The police in some states use those meters for loud cars, and if you are over the limit, you get a ticket.

 

[RegL]

I'd guess 5MPH max -- it is essentially 1/2 as fast, but twice as powerful.

Kent,
Did you look into 2 speed motors? I have seen a little info on them, but not much.

 

[KentT]

Kent,
Did you look into 2 speed motors? I have seen a little info on them, but not much.

Yes, I looked into them briefly. But the price quickly got out of reach...

I think the cheapest were in the over-$600 price range, plus they all had 1.25" hubs, so I'd have needed to get new ones and the fronts are only available from Tazewell. Then, there's the issue of the shifting mechanism....

I also spent some time looking at wheel motors with brakes because of where I'm using it. They were almost as much money, and would've required replacing the hubs also.

So instead, I analyzed the heck out of more common motors, and settled on the Char-Lynn S series. However, I spec'd these with optional high-pressure seals (since the motors are only rated at 1500 PSI max, 1250 continuous -- as I recall) just to be safe, and low-speed valves that supposedly improve the low-speed performance of the geroler-type motors. They were a special order item that I waited about six weeks on...

 

[RegL]

Yes, I looked into them briefly. But the price quickly got out of reach...

I think the cheapest were in the over-$600 price range, plus they all had 1.25" hubs, so I'd have needed to get new ones and the fronts are only available from Tazewell. Then, there's the issue of the shifting mechanism....

I also spent some time looking at wheel motors with brakes because of where I'm using it. They were almost as much money, and would've required replacing the hubs also.

So instead, I analyzed the heck out of more common motors, and settled on the Char-Lynn S series. However, I spec'd these with optional high-pressure seals (since the motors are only rated at 1500 PSI max, 1250 continuous -- as I recall) just to be safe, and low-speed valves that supposedly improve the low-speed performance of the geroler-type motors. They were a special order item that I waited about six weeks on...

Yep. 600 each puts a damper on that idea.