Home-brew mufflers?

Just curious if car enthusiasts sometimes construct their own home-brew mufflers? For improved sound, less exhaust resistance, etc? A muffler seems like a simple enough gadget that a person with time on their hands could make themselves. If only to treat it like a musical instrument to improve the exhaust sound, or just b/c a commercial replacement isn’t available.

Yes, it can be done. But there are SO many different mufflers already for sale for not a ton of money, why would you?


Sometimes I think you have way to much time on your hands and need a better hobby… :laughing:

Why would someone even want to do that unless it was for a race car and even then that is why company’s spend $$$$ on R&D, so you don’t have to… They can also do dyno test to see what makes what better and more power after changes and tweaks, or what ever the public is looking for… One dyno pull alone would blow the budget vs store bought… A muffler can kill a lot of power, or make almost as must power as running open exhaust…


I don’t always have a lot of time on my hands. But sometimes I just need a “project” - like for fun. And I will do things that don’t make sense.

Never a muffler though. I did once “revive” a Dodge Neon, just to see if I could. It didn’t make sense. The car wasn’t worth it by a long shot. But I just wanted to see if I could do it. The “revival” involved removing the head due to a burned exhaust valve. It had been slightly bent, along with it’s partner. I ordered up a couple of those, lapped all valves by hand.

The oil pan had a little leak to, so I pulled that. Checked bearing clearances, which were fine. As long as I was that far, popped out the pistons, and gave them new rings. Ran a cylinder hone (yes, crank in place - stuffed it all full of rags with tack cloths on top. Liberal washdown with brake cleaner).

Put it all back together and it ran great! …for like 10K miles at which point my son ran it into a tree… Ugh. (Other than being shaken, he was thankfully fine. He said he hydroplaned in heavy rain). I’m still bummed - wanted to know how long the dumb thing would go.

More than one person said “why would you do that?” IDK. Just wanted to see if I could…

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Repeatedly building and installing a muffler? No thanks!

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Yeah, a buddy and myself decided we would just scratch build a drop hitch for the old Power Wagon, well all said and done, we had over $50 in metal alone, not to mention the time as well as gas and wire to weld it, then while at a parts store one day we saw a very similar designed drop hitch on the shelf for $49.99 + tax… lol

But I do like the fact that I have built my muscle car with my own hands, but I would never nor have I ever, thought about designing my own muffler…

I’ve thought about it for my generator as there doesn’t seem to be a whole lot out there that you can just buy and install.

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Have you searched for ‘generator muffler’ on Amazon? Pretty wide variety showed up.

Thanks. It’s actually been quite a while since I’ve been thinking about it. Perhaps it’s time to renew the search, although sometimes I think it might be better for me to be able to hear it. In some ways it helps me to manage load.

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MM answered “yes, it can be done”, which comes pretty close to addressing the question asked , close enough for a sol’n by my judgement thx. .

Did you wonder if someone could get some exhaust pipe, drill some holes, cut some sheet metal, and weld up a muffler? Obviously, yes.

I took your question to be could you build one to improve hp and/or sound. That would be very tough without a huge amount of work, and access to a dyno.

While I mentioned sound and flow resistance as possible reasons, my basic question was if enthusiasts sometimes construct their own mufflers? There’s several reasons I can think of why a diy’er might want to build their own muffler. One example, the car is a rare, early not-widely-sold model from the 70’s, and a replacement muffler of the proper size & configuration and meets the flow resistance requirements and has a similar tone & that fits the space, is no longer available. What would you do in that case? Buy a variety of aftermarket muffler and choose one by trial and error? Or would you cut the old muffler apart enough to see how it is designed, then make one yourself w/the same configuration?

There is a huge variety of mufflers available of all different lengths with all different connections sizes. I can think of nothing made since WWII that would justify that amount of work.

Of course, if you’re doing a concours restoration of a '50s Ferrari or a '29 Duesenberg, then all bets are off.

The restoration shop at the museum I volunteer for built a special VW Beetle. The 207 hp 2.6 liter flat 4 got a custom exhaust. This included a custom muffler with factory looking dual tips built by a master metalworker. It was a work of art and did a fine job almost hiding the big engine.

BTW, all the steel except the roof were duplicated in aluminum. It is very fast and handles like a Porsche 911.

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…or a wild custom. Very neat!

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Interesting. It appears the answer is, while not commonly done, yes, custom mufflers are sometimes constructed.

Here you go, George:
Make A Muffler (powernationtv.com)

Pretty cool. I could party with that dude.

As an engineer, I would think you would need some fairly sophisticated sound equipment to do this job properly. What sound are you looking for? What are you willing to live with?

I can easily imagine a whole department of engineers with a dedicated test lab. Plus, these guys would be good at other sources of noise, and since vibrations are closely related, why not combine all this is one part of the organization.

I know! We could call it the NVH group!


I’m simply asking if this is ever done. As posted above, yes, it is done, but as you’d probably expect, not commonly…