resonator internal design

[[486]]

had mixed luck with resonators, always just tossed together whatever and sometimes they work really good and other times they don't work at all
Had a 2" exhaust on my shit with a kia straight-through glass pack thing, it did really good, damn near muffler-quiet
put together a 2.5" with a slightly larger but similar internal construction ford ecoboost resonator and it isn't much quieter than the open downpipe was

is there some kinda magic to this shit?

 

[Benny]

What rpm are you noticing a difference?

I know it's not exactly the same, but when I had a resonator in my straight piped 6.7 Cummins, I really only noticed it helped with the drone at cruising speed. Idle to half throttle was virtually the same.

 

[[486]]

Pretty much across the board from idle on out to a brazillian (like 5.5k)

Reading around I guess they're supposed to be tuned to a specific RPM but the kia one seemed to make it significantly quieter across the board

 

[71PA_Highboy]

too big and you won't develop enough backpressure to make it effective?

 

[[486]]

too big and you won't develop enough backpressure to make it effective?

Maybe. Since I'm replacing one with another I don't think any math is going to be meaningful

Next question; got one of those big 8" diameter stainless japanese spun resonators with the ends cut off and the packing took out (because it was 1.25" pipe through it)
should I stub the inlet pipe in there a ways, or just weld both inlet and outlet on there right at the transition? If I'm having the inlet stub stick in there a ways I could also use a slight S-bend piece to offset the gas coming in so it isn't blowing directly at the outlet.
Figuring on making a big old echo chamber like a 2 stroke's tuned pipe thing, but with zero math or measuring.

 

[arse_sidewards]

too big and you won't develop enough backpressure to make it effective?

Hence why they work so well if there's a muffler behind them.

 

[Firstram]

Helmholtz resonator .

Read up on this and make the length adjustable.

 

[rockota]

Following. My “new to me” 3RZ had an 8” resonator.. replaced with a 12”… hoping it sounds let like a VIN Diesel car

 

[[486]]

Helmholtz resonator .

Read up on this and make the length adjustable.

but then I've got to set it up without a resonator to get the baseline of where the resonance node is, then figure out what kind of thing to do mathematically

Thus, just flailing at it semi-blindly

collective wisdom:
do it like that with the s-bend inside the empty can, or just blob the shit on there like the left side on both ends

 

[M92PV4U]

I don't know the difference between a resonator and muffler . I made two of these for my headers, they fit in 1¼ exhaust pipe. They quieted it down. The inside pipe was ¾ emt. Holes were ⅜ or ⁷/16 and drilled 90° apart all the way around the pipe.

 

[ShaggyAnt]

Loading…

www.matec-conferences.org

Enjoy

 

[[486]]

I don't know the difference between a resonator and muffler . I made two of these for my headers, they fit in 1¼ exhaust pipe. They quieted it down. The inside pipe was ¾ emt. Holes were ⅜ or ⁷/16 and drilled 90° apart all the way around the pipe.

that's a very restrictive muffler

resonator doesn't have restriction, it relies on pressure pulses doing "things"

 

[M92PV4U]

that's a very restrictive muffler

I can't even remember what happened to them

 

[Black Sabbath]

Maybe. Since I'm replacing one with another I don't think any math is going to be meaningful

I once was reading the 100 plus page vibration / resonance report of a piping system downstream of a large reciprocating compressor and quickly determined I wasn’t smart enough to even understand the report never mind even approach the math that is involved. You have to account for all sorts of fun things like pipe lengths and sizes, restraint types and locations, branch connections, compressor rpm, cylinder overlap and impacts of the piping runs before the merge, gas composition and temperature ….. and this was only considering the steady state operation of the system, redo all that math for different rpm ranges for an engine and choose your compromises. One of those topics that has a lot more overlap between a physics doctorate and mechanical engineering then most.

 

[[486]]

ok

just gonna weld it together without the one pipe stubbed in there
just butting both ends like the left one
mostly because it'[ll probably weight less

 

[Donk]

Turbos make pretty effective silencers

 

[Provience]

but then I've got to set it up without a resonator to get the baseline of where the resonance node is, then figure out what kind of thing to do mathematically

Thus, just flailing at it semi-blindly

collective wisdom:
do it like that with the s-bend inside the empty can, or just blob the shit on there like the left side on both ends

Just blob it in there


Without being tuned, it'll still do something.

 

[Firstram]

I once was reading the 100 plus page vibration / resonance report of a piping system downstream of a large reciprocating compressor and quickly determined I wasn’t smart enough to even understand the report never mind even approach the math that is involved. You have to account for all sorts of fun things like pipe lengths and sizes, restraint types and locations, branch connections, compressor rpm, cylinder overlap and impacts of the piping runs before the merge, gas composition and temperature ….. and this was only considering the steady state operation of the system, redo all that math for different rpm ranges for an engine and choose your compromises. One of those topics that has a lot more overlap between a physics doctorate and mechanical engineering then most.

Fuck all of that! Tap in a 24” piece of tubing the same size as the system, use a 90 so it’s parallel to the exhaust. Pick up a tube that will slip over the tube you just added and cap one end. With a little experimentation you should be able to tune it like a rusty trombone

 

[Provience]

ok

just gonna weld it together without the one pipe stubbed in there
just butting both ends like the left one
mostly because it'[ll probably weight less

The more space you leave between your small pipes, the more room the gas flow has to pool and the sound waves have a chance to bounce around

It's really not worth doing more than just stabbing together quickly and easily, for something that is supposed to be quick and easy.

If you want more "effective" you'd have to get into either tuning dead head pipes or adding more direction changes and what not

 

[[486]]

Turbos make pretty effective silencers

Used to have a littler one, now it has a bigger one

 

[[486]]

The more space you leave between your small pipes, the more room the gas flow has to pool and the sound waves have a chance to bounce around

if one of them is stuck in there it doubles the length of the echo chamber because the wave has to go out and back again

 

[Provience]

if one of them is stuck in there it doubles the length of the echo chamber because the wave has to go out and back again

Yeah if you go down decently deep and have the other offset rather than pointed at each opening.

Guess I didn't really look at the pictures, my default is to just be quick and easy, which is to just glue the ends

 

[bdkw1]

Used to have a littler one, now it has a bigger one

Well, the obvious answer is you need 2!

 

[Bowe]

Sorta unrelated, Lennox had some condensers maybe 6 years ago that needed a couple 90s added outside on suction line or they kept people awake from the resonance.

 

[Dethmachinefab]

Here's some ideas. These are for industrial blowers.

 

[[486]]

wouldn't those all be considered mufflers, since they've got like baffles and such?

 

[Dethmachinefab]

wouldn't those all be considered mufflers, since they've got like baffles and such?

Yea I guess so. Just something I had worked on recently that got kind of involved with chamber sizes and frequencys.

 

[[486]]

so the perforated pipe and the fiberglass in there actually does things
the doubly bigger empty can actually made it louder

 

[[486]]

well, made it into sorta kinda a corvair-turbo style muffler

stuck the pipes in there sorta like that, the outlet mashed against the bottom of the can and the inlet mashed against the top of the can
cut a bunch of cutoff wheel slots in them before jamming them in there, was able to weld the loose end of the first pipe to the wall through the open hole, the second pipe I had to cut a little window in the big can to secure it to the case

it is nicely quiet, and shouldn't be too restrictive being that it's all 2.5" pipe in there stem to stern, though it does need to change direction twice in the open volume of the can

 

[arse_sidewards]

I'm pretty sure you just created a bastard version of an OEM barrel muffler just with pipe overlap instead of perforated baffling.