my mistake
i am running a magnaflow 5x11x22 straight through muffler with 3 inch inlet and outlet

 

resonators dont make the car quieter, they change the sound...

we use the vibrant super quiet round muffler inline.. it fits under the car nicely, we usually put them just behind the shift linkage as there isnt much room anywhere else.

one of these (the 3inch in w/single 3inch out.. not the dual tip that pictured) http://phantasmmotorsports.com....aspx

and one of these http://phantasmmotorsports.com....aspx (they call them resonators, but they are built more like mufflers than resonators.. so i call em mufflers)

that combo will make for a nice sounding not too loud exhaust

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by batboyvaj &raquo;</TD></TR><TR><TD CLASS="quote">have you guys ever heard of this method of TOTALLY eliminating drone? sounds interesting

http://www.corral.net/forums/s...96793
</TD></TR></TABLE>
That's AWESOME, has anyone on here tried it? I know on my car the problematic rpm ranges are higher than what these guys on the Mustang board were experiencing, and IIRC, that means a shorter cancellation chamber could be used?

 

wondering if anyone has tried this on a honda

 

Looks like if anyone has, they haven't checked in on the topic today. . .

So, to keep it toward the top of the list here, I'll pipe up that I am definitely up for trying it on a Neon, and conceivably quite soon.

Thing is, I'd like to do something more "intelligent" than just slapping on a perpendicular pipe of a random length. . . I figure there are a couple of potential approaches to take, but my far-from-mathematics-and-physics brain means it will take me a while to figure out unless I can get some help from someone.

Approach #1) One thing that bothers me at times is a loud exhaust note that seems to resonate throughout the car around cruise speed. So maybe I could take that approximate cruise RPM (let's say 3,600RPM for the sake of discussion), and try to use a basic ratio to figure out the length from the length quoted in the other thread for 2k RPMs.

If the author calculated the correct length for 2k RPMs as 26", then maybe I can divide by 3.6, and multiply by 2, giving me an approximate length of 14.4". . . . ?

OR, Approach #2) And this one is pretty close to "just slapping something on there" try to figure out a range of lengths that would cancel some of the high frequencies that make a four-banger sound like one and then tune the length of the. . . . . . . . . Nah, that one isn't making sense to me as I type it, since I read somethings in Wickipedia about resonant frequencies in pipes, and . . . . . well maybe it would work, but I've got to think about that one some more before I even know what to type.

Can anyone help out with some physics/math?

 

It's a good idea, maybe I'll make a tunable one for my 3" when I change rear mufflers this spring. I like doing experiments (and quiet cars)

HKS has been doing this for a while

 

Whoa, I totally forgot to figure in the tube length, which is probably the most important factor in figuring the whole thing out. And then there is the issue of the mustang guy tuning out "tailpipe resonance." The tailpipe on my car is a 2.5" elbow, so I doubt that is a huge deal.

I suppose then, that since my entire system is straight through, I need to either figure my length to calculate the half-wave length from the entire system length, or, maybe if you figure there is wave interuption at the resonator or straight through (magnaflow on one car, dynomax universal on the other) muffler, then I could just work from the tuned length in between?????

Anyone?

 

good god i just nut myself at that HKS exhuast.........wow

 

Yeah, that is NICE! It snuck in there while I was making my last post I guess, 'cause I hadn't seen it.

Also, it's potentially noteworthy that HKS used a curved elbow to the resonance chamber instead of a square elbow which could potentially return some sort of a wave itself (the 90 degree angle that is).

This is INTERESTING stuff!

 

good info so far

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tjabo &raquo;</TD></TR><TR><TD CLASS="quote">Yeah, that is NICE! It snuck in there while I was making my last post I guess, 'cause I hadn't seen it.

Also, it's potentially noteworthy that HKS used a curved elbow to the resonance chamber instead of a square elbow which could potentially return some sort of a wave itself (the 90 degree angle that is).

This is INTERESTING stuff!</TD></TR></TABLE>

they may have just used the bend cause bends are easier to come by? are sound waves affected by bends like air flow?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by batboyvaj &raquo;</TD></TR><TR><TD CLASS="quote">

are sound waves affected by bends like air flow?</TD></TR></TABLE>

Not really, you are essentially creating an air spring that has a certain resonant frequency. The shape does not really change the tuning frequency much. It could be almost any shape that fits. Instead of using a long straight tube like the mustang guys hks decided to use more of a canister shape for packaging reasons I'm sure.

 

i'm wondering how long i would need or how I calc the length i need. Also do I have to use another 3" pipe

del sol, 3" all the way back, resonates around 3-4k cruising.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bailhatch &raquo;</TD></TR><TR><TD CLASS="quote">

Not really, you are essentially creating an air spring that has a certain resonant frequency. The shape does not really change the tuning frequency much. It could be almost any shape that fits. Instead of using a long straight tube like the mustang guys hks decided to use more of a canister shape for packaging reasons I'm sure.</TD></TR></TABLE>Interesting topic. . . . The canister idea changes things as I remember from doing 2-cycle pipes. I'll have to see what I can dig up from the archives of my brain, but basically the divergent cone (think megaphone) creates an effect on the sound wave that causes a negative pressure in excess of the original wave. The convergent cone at the end returns a wave that creates positive pressure. I'll have to ponder what this really does to "tuned length".

I'm so old I can't remember much!

 

here is the same concept but built into the muffler. the muffler is made by corsa and they don't sell any universal ones.

http://www.corsaperf.com/arsctech.htm

http://www.corsaperf.com/arsctech2.htm

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tjabo &raquo;</TD></TR><TR><TD CLASS="quote">Interesting topic. . . . The canister idea changes things as I remember from doing 2-cycle pipes. I'll have to see what I can dig up from the archives of my brain, but basically the divergent cone (think megaphone) creates an effect on the sound wave that causes a negative pressure in excess of the original wave. The convergent cone at the end returns a wave that creates positive pressure. I'll have to ponder what this really does to "tuned length".

I'm so old I can't remember much! </TD></TR></TABLE>

Interesting, aren't you dealing with flow/pulses more than sound when you are tuning thoses things?

 

You know, it seems that the pulses are what you're dealing with when tuning 2-cycle pipes, but IIRC, the calculations were done using the speed of sound. . . .

We'll have to see what the old brain can remember on that topic, because I doubt I can find any of my old notes. It does seem like I ran across one of my old books on the topic within the last 6 months or so. . . If I can remember where to look, maybe that might of some use.

 

i like that canceling idea....I'll have to look into it some more....but im still thinking about doing a stock exhaust with an e cut-out