Asthetic Exhaust note

[faytmorgan]

http://www.corvettefever.com/t...install/viewall.html

[Mbirt]

Ah, that stock C6 muffler looks familiar. I worked in the department that designed it

As for the calculations surround the quarter-wave tuner, you're in luck because it's simply an open-closed duct. Peak transmission loss will occur at the duct resonance frequencies, f=nc/4L, where c=speed of sound, L=length, n=1,3,5 (odd numbers). This only leaves you to figure out the exhaust gas temperature where you plan to install the tuner and the frequencies that you desire to attenuate.

For instance, at a local gas temperature of 350 deg C, the local speed of sound will be 500 m/s. For a length of 1 m, the lowest transmission loss peak frequency will be (1*500)/(4*1)=125 Hz. The next peak will be at (3*500/4*1)=375 Hz.

If Corsa claims they're only targeting 3 frequencies, that would mean there's only one quarter-wave tuner in the maze device that hides inside their flow-through mufflers. I have reason to believe they're targeting the 210-240, 630-720 Hz, and 1050-1200 Hz ranges. This lets you hear lots of 4th and 8th order content at mid-high rpm (350-500 Hz and 800-950 Hz).

Looking at it this way, I believe the quarter-wave branch tuner(s) near the end of your system are the way to go. If you don't know the exact gas temperature at the insertion point of the tuner, it will be easy enough to cut the end off the tube and shorten or lengthen it to get the sound you desire.

[faytmorgan]

Some interesting info here...
http://www.arkperformance.com/...chResults.asp?Cat=13

[faytmorgan]

Originally posted by Mbirt:
Ah, that stock C6 muffler looks familiar. I worked in the department that designed it

As for the calculations surround the quarter-wave tuner, you're in luck because it's simply an open-closed duct. Peak transmission loss will occur at the duct resonance frequencies, f=nc/4L, where c=speed of sound, L=length, n=1,3,5 (odd numbers). This only leaves you to figure out the exhaust gas temperature where you plan to install the tuner and the frequencies that you desire to attenuate.

For instance, at a local gas temperature of 350 deg C, the local speed of sound will be 500 m/s. For a length of 1 m, the lowest transmission loss peak frequency will be (1*500)/(4*1)=125 Hz. The next peak will be at (3*500/4*1)=375 Hz.

If Corsa claims they're only targeting 3 frequencies, that would mean there's only one quarter-wave tuner in the maze device that hides inside their flow-through mufflers. I have reason to believe they're targeting the 210-240, 630-720 Hz, and 1050-1200 Hz ranges. This lets you hear lots of 4th and 8th order content at mid-high rpm (350-500 Hz and 800-950 Hz).

Looking at it this way, I believe the quarter-wave branch tuner(s) near the end of your system are the way to go. If you don't know the exact gas temperature at the insertion point of the tuner, it will be easy enough to cut the end off the tube and shorten or lengthen it to get the sound you desire.

Please check your Private Messages.

[faytmorgan]

straight pipe e92 m3 v8 sounds like a ls series camaro
http://www.youtube.com/watch?v=V27hrX5Nh48

so a proper x pipe and muffler design should bring it to that ipe f1 sound...

one thing to mention is, does the distance of the x pipe from the valves make a difference here? Not for power, but for sound alone?

[faytmorgan]

I ended up going with a highly modded schoenfield 180 header.

[AxelRipper]

Any pics? 180s are awesome, and I can't imagine what they look like in a Z car

[DannytheRadomski]

I did forget to mention that (as far as i know) all inline 4s use a flat plane crankshaft.

The Yamaha YZF R1 has a crossplane crankshaft, and I think there's one more but I can't remember.

[Adambomb]

Originally posted by DannytheRadomski:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I did forget to mention that (as far as i know) all inline 4s use a flat plane crankshaft.

The Yamaha YZF R1 has a crossplane crankshaft, and I think there's one more but I can't remember. </div></BLOCKQUOTE>

Yeah, when the crossplane R1 came out there was a lot of marketing hype about that. I laughed, because at the time my '88 Ninja 600 also had a cross-plane crank. It was awesome. It sounded like a Ferrari. In fact, I think that a large portion of the Japanese 4's from the late '70s to early '90s were cross plane. They did it because that configuration is inherently more balanced than an even-fire, which they needed to do to break the 10,000 rpm barrier with that tech.

Then sometime in the '90s they figured out how to make the bottom end live with even-fire, and also discovered that pulse tuning was a lot more effective with even-fire, and that's what most have been since then.

Here's something interesting: Took a recording of the bike at WOT, then imported a .wav file into Matlab and did a specgram of it (think of it as a series of FFTs across time, with a color map so red = high intensity, etc).

'88 Ninja 600 specgram

[englertracing]

http://www.youtube.com/watch?v=ZcAQr...gcQby5kQlGZACA

I found this muffler design, seems to make things sound higher pitch and raspy.
the 96 car (mine) and the white car run similar rpm (not camshafts tho)
and mine sounds verry different.
its obnoxiously large, 10" diameter and 29" long. with a .5" gap around the inside cone

being a 4 cylinder i already have 180 exhaust system by default, i think you should build 180 headers or just run 8 into one, or a system 4-2-1 180 style.

http://www.youtube.com/watch?v=ShSIXh04K7U

does this sound exotic enough for you?