To muffle or not to muffle?

[ultralight01]

So I'm enjoying my kart but, of course, the straight pipe is loud as heck. I have an idea for a muffler that is very DIY and kinda trashy, but I've held it up to my exhaust pipe while it was running and it sounds great. My question is, will I need to adjust the carburetor to avoid making the mix too rich?

The "muffler" is a spray paint can with a hole in the bottom, and a hole on top.
Pics:

On the iPad so only one pic at a time. One moment please...

 

[ultralight01]

 

[ultralight01]

Done. For some reason, iPads only allow one pic per post. It does not make sense.
My plan is to weld the can on, wrap it in fiberglass to make it look decent, and drill some holes in the sides. Is that doable without harming the engine or fuel ratio?
Thanks
This is a steel can and a long pipe. I know it will not melt.

 

[Hellion]

Actually, you would want the outer part intact and a perforated inner core, that is itself wrapped in a layer of fiberglass.

Say, for instance, have the inner core the same diameter as the rest of the pipe. Drill holes in the inner pipe much like the cooling jacket of a machine gun.
Gewgle the anatomy of a glass pack, straight thru muffler for the general idea.

I wouldn't weld it on. See if you can braze on a short length of pipe so you can make it a slip-fit on the header and fasten it with a hose clamp.

Nice shoes--what are those?

 

[Whitetrashrocker]

What Hellion said.

As you have it now is more of an expantion chamber or resonator. In short, changing the pitch and it's not so annoying on the ears. And probably minimally quieter.

I can't remember exactly how I did it but I made a similar design out of some heavy cardboard tubes that resembled a glass pack for a vacuum pump exhaust I had to operate for long periods at a time. It toned it down and I saw no effect on the pump.

 

[mckutzy]

Got the start for a glass pack for sure...

 

[Hellion]

What Dr. Mckutzy^^ said.

How come there's no (to my knowledge) factory glass packs (Cherry Bombs) for small engines? They muffle the sound--also give it tone and yet offer very little restriction.

Has anyone taken apart the Briggs style "sausage" muffler and wrapped the core in fiberglass?

 

[ultralight01]

So why do I need an inner core? I'm thankful for the advice but I have questions still. The can alone seems to muffle is quite well. Wouldn't a pipe with holes not let as much air into the outer sheath, meaning less "muffling"? Or does an inner core do a better job?

 

[Hellion]

Go with it then, you are the final judge. Do it and come back here with a review and a before and after video.

However, maybe we have a misunderstanding. You said, "wrap it in fiberglass to make it look decent". Did you mean fiberglass insulation or fiberglass header wrap (tape)? The former is not decent; the latter looks decent, especially with all the fashion colors they have available now.

 

[ultralight01]

I meant the wrapping. But really, I'm asking for advice. That's why I asked, is having an inner sheath definitely better? And my original question, would I need to adjust the jet and fuel/air mix with this? I respect this forum and its members a lot and I'm not gonna be the guy who does it my own way just cause I want to.

 

[mckutzy]

Well if you have upgraded the intake, and now have the new header, then yes you'll most likely need to rejet.
The muffler wont have much an effect with the rejetting however...

 

[ultralight01]

The engine came factory set for this header and intake, no upgrades were done by me.

 

[Hellion]

The muffler should have no effect on running lean or rich. Glad we have a two-person consensus.

If what you have made works to your satisfaction, go with it. Maybe we are all overthinking this muffler and all of our suggestions are to make it work, work well and last for a while and you may not want any or all of that. It's an "old school" mentality that you may not actually understand or even possess for that matter. It's all good though.

ADDENDUM: Ultralight01, have you even tried the muffler I shared in post #7? You'd have to see if the diameters match and I think those mufflers come in 3/4" or 7/8"...maybe 1"...

 

[tinamcjittles]

Inner sheaths are better for muffling if that is what you are asking, it allows the air coming out of the muffler to lose pressure and velocity.. Like in the picture above with small holes punched at an angle to pick up some of the exhaust.. it gives it a deeper muffled sound, I actually love the tone from the holes and sheaths but each to his own

 

[ultralight01]

I have not tried the muffler in post 7, where could I get one?
I could make a cherry bomb, it would simply require more time and resources. Where would I get the outer sheath/chamber?

 

[Jfive]

I'd do it like hellion suggested. I'd use loose fiber glass vs wrap just to add with sound cancelation. I have the Briggs muffler purchased from true value for cheap. I like your paint can though.

 

[ultralight01]

If what you have made works to your satisfaction, go with it. Maybe we are all overthinking this muffler and all of our suggestions are to make it work, work well and last for a while and you may not want any or all of that. It's an "old school" mentality that you may not actually understand or even possess for that matter. It's all good though.

I love that mentality Hellion, even if I'm only 15. Yeah, that's why poboy thinks I'm so gullible and I've had a hard time understanding things. Go karts have been my first real mechanical inclination.

 

[mckutzy]

I saw this thing on the Pinterest a little wile ago...
A press for the baffle dents...... Could be used for a host of dent sizes or shapes, aswell as louvers in other pieces....
Just slit the tube and press in the dent...

 

[chancer]

I have seen the one like hellion Posted "the Briggs sausage" type. Where someone simply Drilled out the center.

 

[ultralight01]

I'll test out the can and how it sounds today. If I think it could be better I'll make the cherry bomb style, IF I can find an outer chamber that I can weld on. The method Mckutzy posted is awesome! That would do a great job at making dents and diffusing the air.