Asthetic Exhaust note

[faytmorgan]

Originally posted by Charlie:
F1 cars operate in a frequency range that is nothing like any production car. It should not surprise you that their exhaust note is different.

i doesnt surprise me. the volume of air they can produce at the higher rpm puts the note achievable at a lower rpm range at a higher octave from the cfm produced. what surprises me, which you miss read, was the ipe f1 exhaust system. this is not an f1 car exhaust this is exhaust that attempts to mimic said note. it is very close to sport bike volume and note. which that in itself is close enough to me. the issue in purchasing such a product is that ipe does not sell the product for my custom made car, and for two even if they did it would be (as is the m3 exhaust sold) it would be in the upper 5k us dollar range.

if i could figure out exactly what they did i could make a system with waaaay less money. i am a custom metal fabricator at a reputable company, that allows me to make things for myself with permission.

[Mbirt]

Compare the IPE F1 on an M3 at 1:03: http://www.youtube.com/watch?v=t2iiFBZuLOc

To the various setups on a C6 Z06 here, especially the final iteration with corsa mufflers: http://www.youtube.com/watch?v=B6uAVZf-BMM

I don't think there's any magic to the IPE F1 exhaust. Good, even mixing of pulses with good headers, x-pipe, and overall system symmetry combined with mufflers that target the lowest frequencies for drone prevention but not the 200-900 Hz range that you want to hear. The IPE F1 M3 system achieves extra rasp to imitate flat-plane v8's with the use long pipe lengths without tuning elements except for the long x-pipe and mufflers.

I think you should replicate the IPE F1 system for your car and put Corsa RSC mufflers at the end.

[faytmorgan]

could you explain this in more detail? the actual engineering tidbits behind it i mean.

[Charlie]

Originally posted by faytmorgan:
what surprises me, which you miss read, was the ipe f1 exhaust system. this is not an f1 car exhaust this is exhaust that attempts to mimic said note.

Sorry I misunderstood.

[faytmorgan]

Originally posted by Charlie:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by faytmorgan:
what surprises me, which you miss read, was the ipe f1 exhaust system. this is not an f1 car exhaust this is exhaust that attempts to mimic said note.

Sorry I misunderstood. </div></BLOCKQUOTE>

No problems, my typing could be the issue. I broke a few fingers on my left hand so...

[Mbirt]

Hopefully my sloth in formulating a response is giving your broken fingers some needed recovery time, faytmorgan. That's my glass-half-full view of procrastination.

I guess I need to know the specific questions you're asking to know what to elaborate upon.

It seems that there are many Corvettes with exhaust sound similar to the IPE F1 M3 system, typically with long-tube headers, aftermarket x-pipes, and Corsa mufflers. If each cylinder sees the same duct geometry for sending pulses to the X-pipe, the sound leaving the x-pipe will be the closest possible to 180 degree headers. I'm sure various changes to the x-pipe could change the sound, but it's hard to tell what would happen without testing it yourself. I would just use a y-pipe and have one nice, orderly conga line of pulses for scavenging.

For an interesting comparison, watch this back-to-back with the IPE F1 M3 and the Corvette with 180 degree headers from your original post: http://www.youtube.com/watch?v=i-cV1aZ_X3M

The Corsa Xtreme system for a C5 looks like this:

That is simply a low-frequency tuning element which has no flow passing through it. Corsa is attenuating frequencies in the sub-200 Hz range to keep its claim to fame of no cabin drone. The simplest possiblity is that it's a Helmholtz tuner with relatively broad tuning due to a short, large diameter throat. The more complicated possibility is it incorporates the convoluted Corsa quarter-wave tuner maze-like device inside the oval shell. Either way, it's a high-pass filter for the purposes of eliminating drone and an "exotic" sound.

The Dinan E92 M3 mufflers that you posted the tech writeup for go one step further with absorptive tuning after the Helmholtz tuning. If you want a more civilized sound, the absorptive tuning will hit the 500+ Hz range. But, after watching FFT plots on my phone during v8 Ferrari clips on youtube, this is exactly the frequency range you seem to desire more of.

[faytmorgan]

In my original post I have an image of a corsa cutaway.

here it is again.
http://i938.photobucket.com/al...aytmorgan/Corsa1.jpg

[Mbirt]

Originally posted by Mbirt:
The simplest possiblity is that it's a Helmholtz tuner with relatively broad tuning due to a short, large diameter throat. The more complicated possibility is it incorporates the convoluted Corsa quarter-wave tuner maze-like device inside the oval shell.

I agree that's what the quarter-wave tuner in their standard flow-through muffler looks like. The C5 Corvette setup is obviously different. They could be Helmholtz tuners. Either way, they're a means to the same end--low-frequency attenuation.

[faytmorgan]

the problems i see with this is that tuning for a particular range, as previously stated, there is a freq peak and i havn't a clue on the math for that...

[faytmorgan]

also i should note that corsa has said themselves it is 3 particular freq that they are trying to cancel. i would like to see inside those vette mufflers... hmmm