Resonator on a 3" exhaust?

[Jon]

Just a quick addition to this thread as a potential option for those looking at quieting things down.
I just rehung my exhaust system and removed a previously installed Car Chemistry collector insert. I had it installed right before the central silencer (about 24" after the cat.). It did make a hell of a difference at cruising speeds (45 and up). Now without it, looking at less restrictive options... J pipe might be the answer!

[F22Chris]

I said that in the first page but I was wondering on the math behind it, thanks Erik!
They should be called cactus pipes.

[GhostAccord]

J-Pipe??? as in a resonance chamber?

I have seen those on a few older, high priced, luxury cars. They are very effective for removing drone, aka resonance or specific frequencies from exhaust systems. Same thing Honda does to it's intake systems. All those little J and kidney shaped objects stuck to the intake tube are resonance chambers. Adding one to your exhaust would be fairly easy, if you have access to a welder.

The math behind the magic could be found using Helmholtz resonator. Or there are a number of web pages of information and some calculators that might be able to steer you in the direction you are looking. All this being said, you will need to know the range of frequencies that you are looking to cancel. That or just start sticking different sized tubes onto your exhaust in different locations...lol

There is a lot of science and R&D that goes into designing powerful intake and exhaust systems that remain quite.

[illinois_erik]

hey welcome guys, the pic is just a representation, it can be any configuration and itll be way different for our cars..think of it like a sub box port tube..if the numbers are there itll work wether a straight line L or a J or a T maybe even an S but then youll have reflection variables. some show on YT some kids trans am or w/e it was an arm lengths piece J shaped right before the muffler and seemed to make a difference (it was set up for highway drone)




Ive wondered how well something like the J pipe,resonator and a twin loop muffler would work.

[GhostAccord]

It's all trial and error, R&D. Unless you want to get into the resonance frequency, fluid and thermal dynamics of it all? A 5.7L V8 with 2.5" dual exhaust will react differently than a 2.2L I4 with 2" single exhaust. Will it work... yes! How well, depends on the setup.

[Raf99]

So my question is does a J pipe affect performance?

And my other thought was how ironic that the 04 TSX I have is a 4 cylinder as well as the cb7. But wow... What a difference in sound. I love love to have the TSX exhaust on the cb7. Has anyone ever done dual exhausts on the cb7?

[sonikaccord]

So my question is does a J pipe affect performance?

And my other thought was how ironic that the 04 TSX I have is a 4 cylinder as well as the cb7. But wow... What a difference in sound. I love love to have the TSX exhaust on the cb7. Has anyone ever done dual exhausts on the cb7?

Yes. It would affect your pressure wave energy. Will it be measurable...probably not, especially since you are turbo'd.

It's all trial and error, R&D. Unless you want to get into the resonance frequency, fluid and thermal dynamics of it all?

I want to get into that...I have my thermal dynamics book around here somewhere. I should've taken mechanical engineering...I'm starting to do alot of reading on combustion, compressible fluids, non-compressible fluids, etc. Self study is free for what I want to do though.

[GhostAccord]

I want to get into that...I have my thermal dynamics book around here somewhere. I should've taken mechanical engineering...I'm starting to do alot of reading on combustion, compressible fluids, non-compressible fluids, etc. Self study is free for what I want to do though.

We covered fluid and thermal dynamics in my Pipefitter/Steamfitter Apprenticeship as it pertains to gases and fluids flowing through pipes. More than enough information to use for building intake and exhaust systems. I then took it to the next step and started learning about resonance tuning and added that to my build calculations. R&D is the next step.

[gloryaccordy]

Anti-drone pipes maybe? They bounce back the same frequency as the exhaust puts out to rid drone.

https://www.performancetrucks.net/fo...-drone-489463/

This is the move. Find out what frequency it is droning at and build a Helmholtz resonator. The math is pretty involved, but it really works and is very customizable. My dream is to build such a system for my G37.

Another option is to run a turbo style muffler. Cheap and effective, though it might take a little edge off the absolute top end. And at 3" you should have enough flow.

[Bunta]

Wouldn't it just be easier to build one of these J-pipes with a slip joint so you could vary the length of the straight section until you got the result you wanted?

[Raf99]

Wouldn't it just be easier to build one of these J-pipes with a slip joint so you could vary the length of the straight section until you got the result you wanted?

lol..... a trombone? that i can control with a string haha...

But ya, don't believe there's room for a J pipe on the cb7, unless its hanging down or in the rear somewhere....