Mufflers for residential engine dyno

[ka67_72]

I'm back at playing with my home built dyno. It has a twin turbo 454 on it now. I fired it up today very briefly with open exhaust. Then I took it outside and bolted some Flowmasters straight to the manifolds. This thing is way louder than the single turbo small block I had on it before. I'm thinking about building a "dyno shed" with a semi anechoic, exposed fiberglass interior and some wicked mufflers. My nearest neighbor is about 100' away, the rest of them are retired. Is quiet dyno testing a pipe dream? Mufflers are $15 ea from Pull-A-Part. Could I stick 10, 300 hp Caddy/Lincoln mufflers in parallel and quietly make 1200 hp?

Thanks,
Kevin

[yellomalibu]

You could make a pair of custom mufflers. Start with a pair of these:


If the pic didn't work, it's a 55 gallon drum.

[MR P-BODY]

I was looking at buying a dyno and I was going to sink a 250 gal
home heat oil tank in the ground as my muff.... I live in the country
per si but big dollar homes are somewhat near

[DanStokes]

Depending on what we were doing, we usually ran the exhaust thru a Constant Volume Sampler and the building exhaust system so noise usually wasn't much of an issue but sometimes we ran pipes out the back door. We used various mufflers over the years and they had varying effectiveness. Basically, you have to try some and see what flies. We never had much luck with Flowmasters, though. Seems like Magnaflos were often the best, IIRC.

Have fun
Dan

[Orange65]

You might try 18 wheeler mufflers. We had one on our small engine test building with all the small engines exhausting thru it. There were houses 75' feet away and we never got any complaints. The muffler was turned straight up.

May not be a reasonable comparison- we were testing up to 20 HP engines (up to 15 at a time). I think you are making a little more power.

[milner351]

I'll put in a second vote for big rig mufflers - they are designed to take a lot of heat for a long period of time - are large diameter in and out, and quiet down some pretty enormous engines. Back at Torque in the mid 90's we had a big pair of them on the roof with rain caps - it was still loud inside the room from all the air flow, etc, but outside it sounded about like the UPS truck accelerating up the street.

[dieselgeek]

Look around on some of the other forums. Perhaps contact Jay Brown. I don't think you want to run mufflers, at all. What you need is something to diffuse the sound without adding backpressure...

I've been to Jay's home dyno a few times and he has a large plywood box that he pumps his exhaust through, I'm not sure what's inside it but it looks affordable and REALLY cuts down on the noise.

Maybe hit him up on www.fepower.com

-Scott

[ka67_72]

I built a single muffler for my last motor out of a 40 gal gas water heater. It somewhat worked. I read an old post on another forum about muffler tanks. They sounded like septic tanks filled with crush and run. Any experience with something like that? I agree with the no muffler idea. www.fepower.com seems to be down. As far as exhausting into a box, I was thinking of something similar with a rectangular chimney like a folded transmission line. It would be high flow with an exhaust fan on the exit but the sound would have to make several 90 degree turns into fiberglass lined walls on the way out.

Does anyone have any idea why I only get an e-mail for the first response?

Keep the ideas coming,
Kevin

[PatricksDad]

I built a single muffler for my last motor out of a 40 gal gas water heater. It somewhat worked. I read an old post on another forum about muffler tanks. They sounded like septic tanks filled with crush and run. Any experience with something like that? I agree with the no muffler idea. www.fepower.com seems to be down. As far as exhausting into a box, I was thinking of something similar with a rectangular chimney like a folded transmission line. It would be high flow with an exhaust fan on the exit but the sound would have to make several 90 degree turns into fiberglass lined walls on the way out.

Does anyone have any idea why I only get an e-mail for the first response?

Keep the ideas coming,
Kevin

I'm pretty sure that Jay's site is www.fepower.net, not .com

[TC]

I'll put in a second vote for big rig mufflers - they are designed to take a lot of heat for a long period of time - are large diameter in and out, and quiet down some pretty enormous engines. Back at Torque in the mid 90's we had a big pair of them on the roof with rain caps - it was still loud inside the room from all the air flow, etc, but outside it sounded about like the UPS truck accelerating up the street.

X3, on the big rig mufflers

Look into these, this is what one of the guys over at SpeedTalk said he was using, it's a Peterbuilt Muffler.........

(Donaldson M110824 G019A) it's a 5" inlet and outlet about 12" diameter and 4' long

With a muffler this big back pressure concerns won't be a problem.....

[TheSilverBuick]

Eff the neighbors. It's not like you can hear them complaining next to an un-muffled big block at 6,000rpm anyways

[PatricksDad]

Eff the neighbors. It's not like you can hear them complaining next to an un-muffled big block at 6,000rpm anyways

Awesome.

[Caveman Tony]

I think a big metal container or 'rig' mufflers could potentially just act as resonance chambers, defeating the purpose.

A healthy sized plywood box with some strategically placed reflectors and copious amounts of fireproof absorbent material might be the best option... and potentially the cheapest.

I'd cut open a modern quiet OEM muffler for geometry design ideas. Just make sure the exit is bigger than the inlet, and I don't think you'll have back pressure issues.

[dieselgeek]

Barton Racing has the gigantic mufflers, look like they come off something Randal works with. They do not quiet down much, here's some audio of a tamed down pro stock Hemi

[ka67_72]

I shot Jay an email.

I can't eff the neighbors. Even though the retired guy next to me spends 3 hours, sometimes 3 times a week mowing his 1-1/2 acre yard on a $9K zero turn with Armor All on the tires and sounds like a helicopter hovering over the house. Mine takes an hour wide open in sixth gear. Maybe once a week. My mower burned down in a fireworks accident. He said I should get one like his. I won't pay that much for a car!

I've seen other posts about truck mufflers and seen other videos with big mufflers. I think they'd work fine if I were in an industrial park, but I'm not there yet. I wanted to build a small building near the house but I already have a 10X12 shed in the back corner of the yard. Since this is an experiment, I'd like to keep the costs down. The only problem is it's full of junk.

This is normal, right?