Asthetic Exhaust note

[faytmorgan]

I am here posting this upon recommendation of the knowledge base.

This is all in relation to a 90 degree v8
I am looking for the highest frequency/note/tone/pitch I can get. I very much enjoy the higher, crisper, cleaner sound the european v8 makes. I hate with a passion the rumble of the harley/dumptruck American v8. I have heard flowmasters on these cars. I don't know if it was the particular flowmaster series or what. But that m3 was a dumptruck. I am trying to avoid that.

I do not need to be informed about flatplane cranks vs crossplane.

I am lost in design at this point. I have a few options as I see it, x pipe, headers, and muffler designs.

Maserati has used ferrari engines since they were bought out by fiat. They use a cross plane crankshaft instead of a flat plane. They also use tri-y headers factory and an x pipe further back toward the mufflers.

http://en.wikipedia.org/wiki/F...ons]Ferrari/Maserati (http://en.wikipedia.org/wiki/Ferrari/Maserati_engine#Shared_specifications%5DFerrari/Maserati) engine - Wikipedia, the free encyclopedia
http://cars-database.com/data_...8/maserati-v8-03.jpg (http://cars-database.com/data_images/models/maserati-v8/maserati-v8-03.jpg)
a similar snarl that the Corsa gives the Domestic V8
http://www.youtube.com/watch?v=Un_sQtJA2iA]Maserati (http://www.youtube.com/watch?v=Un_sQtJA2iA%5DMaserati) GranTurismo Exhaust Note! - YouTube
http://www.atzonline.com/index...2a814fd6b316776454]A (http://www.atzonline.com/index.php;do=show/site=a4e/alloc=1/id=7929/sid=210295707550b72a814fd6b316776454%5DA) New V8 Engine Powers the Maserati GranTurismo S - ATZ online
x pipe
http://www.ebay.com/itm/08-Mas...590912#vi-content]08 (http://www.ebay.com/itm/08-Maserati-Gran-Turismo-4-2-complete-oem-exhaust-mufflers-silencers-/140868590912#vi-content%5D08) Maserati Gran Turismo 4.2 complete exhaust mufflers silencers | eBay
The illustration shows Exh mani as a 4 into 1 design, shorty, primaries appear to be equal length. X pipe is a ways downstream
http://www.maseratispares.com/...tegories/492_023.jpg (http://www.maseratispares.com/1998-heden/images/categories/492_023.jpg)
same 136 engine only the tipo f136 has a flat plane.
http://www.youtube.com/watch?v=gwVlcgSUO0A]Ferrari (http://www.youtube.com/watch?v=gwVlcgSUO0A%5DFerrari) 458 Italia Exhaust Sound!! Lovely Downshifts! - 1080p HD - YouTube

the alfa uses the same cross plane motor as the maserati. very similar. I am sure the slight differences of video quality and the bends in the exhaust that differ between the two can attest to the very slight difference in sound.- still sounds like a domestic with corsa's and an x pipe.
http://www.youtube.com/watch?v=0siqvB_7Sco]Alfa (http://www.youtube.com/watch?v=0siqvB_7Sco%5DAlfa) Romeo 8C Competizione Sound!! - 1080p HD - YouTube

How about we turn to something that takes a traditional 90 degree motor (with itbs, dohc heads, and di) that uses tri-y headers and an x pipe factory.

The s65 bmw motor is a lovely motor.
sounds like a small block chev on the dyno to me, buts its the bmw m3 s65 v8.
http://www.youtube.com/watch?v=Y-mGGf5Ncx8]s65 (http://www.youtube.com/watch?v=Y-mGGf5Ncx8%5Ds65) BMW Engine Dyno - YouTube

compare that to this full exhaust system by ipe f1
https://www.youtube.com/watch?v=SbT0IqFIfnc

compare that to this
http://www.youtube.com/watch?v...&feature=related]E92 (http://www.youtube.com/watch?v=BzvpgQcszFs&feature=related%5DE92) M3 Exhaust Compilation - YouTube

and lastly compare those to this
http://www.youtube.com/watch?v...&feature=related]E92 (http://www.youtube.com/watch?v=MIsc_9FLLIM&feature=related%5DE92) M3 - Megan exhaust - YouTube

there really has to be more to it than the natural sound of the motor... I would agree that it is more than JUST one thing.

"The crank pin offset is 90°, and for design reasons, a cylinder firing order of 1-5-4-8-7-2-6-3 was chosen
for the S65, instead of the typical 1-5-4-8-6-3-7-2 firing order more commonly employed in other BMW V8 engines."
if you can make some sense of that- its odd "Cylinder numbering is 1 through 4 on passenger (right) side and 5 through 8 on driver (left) side. numbers 1 and 5 are at the front, 4 and 8 are at the rear."
http://blog.bavauto.com/10109/...yl-6-cyl-v8-v12/]BMW (http://blog.bavauto.com/10109/bmw-engine-firing-order-and-cylinder-location-bank-1-bank-2-4-cyl-6-cyl-v8-v12/%5DBMW) Engine Firing Order and Cylinder Location (Bank-1, Bank-2), 4-cylinder, 6-cylinder, V8, V12 | Bavarian Autosport Blog

Apparently, the fireing order is the same as the BMW Sauber F1 team v8.

check out this s65 header. looks like a tri-y to me.
http://img364.imageshack.us/im...3289/dscn0632nb7.jpg (http://img364.imageshack.us/img364/3289/dscn0632nb7.jpg)

http://www.epi-eng.com/piston_...chnology.htm]Exhaust (http://www.epi-eng.com/piston_engine_technology/exhaust_system_technology.htm%5DExhaust) System Technology: Science and Implementation of High Performance Exhaust Systems

http://www.billswebspace.com/D...austDesignReview.pdf (http://www.billswebspace.com/DinanE90-92ExhaustDesignReview.pdf)
https://www.youtube.com/watch?v=J9u6jI3lRCw
The x pipe from the above video.
http://maxcdn.nexternal.com/aaw/images/Large252.jpg

I think the only reason that the ipe f1 exhaust is higher has to be that x pipe design. which is shown in the following link
http://i244.photobucket.com/al.../20120917_221533.jpg (http://i244.photobucket.com/albums/gg16/dannyeatworld/20120917_221533.jpg)
http://i.imgur.com/batEA.jpg
(not to scale dims) Note the taper of the x pipe and the hole that makes the air pass through a smaller opening on two ends. If you look very close at the x pipe design, its ALMOST as if its two x pipes in one.
http://i17.photobucket.com/alb...-pipedimsactual2.jpg (http://i17.photobucket.com/albums/b81/BRAAPZ/BMW/X-pipedimsactual2.jpg)

Now one thing to consider is the are resonators that cancel out particular noise. this is what Corsa mufflers do. The have chambers in the mufflers (which is more like an instrument than a traditional muffler) that are helmholtz resonators that are VERY small. They shoot for 3 particular resonate frequencies to cancel out. Now one thing about frequency is that it peaks, there is a range at the peak. The range will depend on many things and without actual testing it is not possible to know the range with math (that i am aware of to date).

http://en.wikipedia.org/wiki/H..._resonance]Helmholtz (http://en.wikipedia.org/wiki/Helmholtz_resonance%5DHelmholtz) resonance - Wikipedia, the free encyclopedia

In use on an exhaust system
http://forum.grrrr8.net/showthread.php?t=10801]Capped (http://forum.grrrr8.net/showthread.php?t=10801%5DCapped) Helmholtz chamber (Drone Eliminator)

Now if you actually understand the above link you will see that they are utilizing a Helmholtz Resonator and then packing around it with fiberglass to bring down the vibration(vibration of any kind will bring the volume of the devise up- so this muffles it).

the purpous of a "muffler" is to MUFFLE sound not change the actual tone.

the corsa i wouldn't even call a muffler per say. I would say it is more similar to the dr. gas freq mod, but a better design.
http://freqmod.drgas.com/]FreqMod (http://freqmod.drgas.com/%5DFreqMod) Mufflers
corsa cut away
http://s938.beta.photobucket.c....jpg.html?sort=3&o=0 (http://s938.beta.photobucket.com/user/faytmorgan/media/Corsa1.jpg.html?sort=3&o=0)

I should also note that ferrari motors that have a 180 crankshaft do not require an x pipe to merge the exhaust pules efficiently because they already do that naturally with the design of the crankshaft (and firing order of course that goes along with it).

oh as for the 180 header. I suppose I should post this- one of many, videos of a sbc with 180s sounding exotic as they do. The kelmarks, grant gts, and many other cars use these headers as well (gt40s too).

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

http://www.youtube.com/watch?v=MSZTbR6C6Lw]Corvette (http://www.youtube.com/watch?v=MSZTbR6C6Lw%5DCorvette) with 180 Degree Headers - YouTube

The complete setup of the engine.
4.060 bore (3.25 stroke) inches
team g intake single plane manifold
jegs 195cc intake port, 64cc chamber heads aluminum strait plug
Superflow sf 600 flow com
air speed: 380-100FT, 375-410SC

Intake;
(.1)66
(.2)141
(.3)200
(.4)242
(.5)270
(.6)265
(.7)268

Exhaust;
(.1)55
(.2)107
(.3)139
(.4)167
(.5)192
(.6)209
the cam will be setup for the intake/heads/headers that are selected in the end result. The cam will put the engine in the 3000rpm-7000rpm range and a redline of 7500, albeit will be designed around the intake/heads/headers flow etc.
The compression will be at 10.5:1, so as to utilize pump gas.
Forged crankshaft (small journal block, two bolt) cross plane style crank shaft I am not going to swap in a 180 crank (flat plane) as per Ferrari spec much too much work and $$ to do such a thing.
I have decided I should pony up for 6" rods
the rockers are at a 1.6 ratio.

The engine is designed around the fact that I wanted a specific rpm range, the car is very light and tires are very limited. The max tread width I could find in the max rim size available was 8.5 inches. The section width of the tires are 245mm. The rim itself when measured end to end was 240mm. The car will weigh in at about 2800lbs. The donor car is a 1978 Datsun 280z five speed which is going through a sbc v8 conversion. The drivetrain (axles, transmission, and differential) that are available can hold to the hp (which I realize is tq(rpm)/5252). So the rpm of the motor has been raised to the 7000rpm mark to best match the transmission ratios and differential ratio as well as to produce more peak hp than low end tq. Too much tq will just cause the tires to spin and cause premature part failure.

So aside from the use of 180 degree headers (which are a pita) what are my options here. I feel I am lost at this point. Could I get some help here on my personal weekend racer project?

Fayt~

[faytmorgan]

nothing?

[Owen Thomas]

It's hard to tell what information you're looking for, so it is difficult to pose a response. You have some good information linked your post, and know more about the application than we possibly could, so it seems like you would be better off coming to your own conclusions.

But, I'll try my hand. I read something in that mess about specific hemholtz resonators used as a silencer, and have heard of it before. Theoretically, if you could make a series of resonators designed to cancel (attenuate) some of the lower frequency ranges, the exhaust note *should* sound higher. Also of interest, although probably not very practical, is that increasing the local speed of sound of your exhaust gas will also increase the pitch. This is most easily accomplished by raising the temperature (c = sqrt(kRT)), but it is already very hot, as I'm sure you are well aware.

It is worth noting that ignition timing can also change the way the engine sounds, but I do not know any specific trends or rules of thumb.

[DannytheRadomski]

The Ferrari F430 made a great sound. The reviews I've heard about the car make it sound a bit cold, but the exhaust note sounds incredible.

[faytmorgan]

Thank you for taking a stab at the least. I waited four days. You fellas are supposed to be some of the brightest minds technically on this subject from my understanding. Hence why I am here. Over thinking =good in regards to this.

Is there a way, (dynamically) without raising temp per say, just based on design of the tubing itself (shape) that one could increase the speed of sound? I am stuck in the no less than 2.75 inch diameter range, past the collectors- for power level reasons alone (500 plus hp).

As to the Helmholtz res. It only cancels out a small range of freq. (when done right) the range is the freq. peak. I would have to have a large amount of resonators to cancel out the noise undesired.

I am attempting to avoid 180 degree headers. I know that those headers will reproduce the sound I am looking for. I do not understand how IPE f1 exhaust (as posted in the links above) got such a high pitch. The only thing I can think of is the design of their x pipe (dimensions and picture in the above links). I am thinking that with a tri-y design and the proper length of the primaries and matching of course, that one could reproduce the 180 pulse. What I can't find anywhere is how to determine length so the correct pulses meet up in the separated headers when they are connected with an x pipe, if you follow me. With the 180 pulse copy using the tri-y and the x pipe in the correct location as almost part of the headers I have a theory this would recreate the sound I am after without the 180 degree headers.

Aside from that, I am out of ideas. Anything ingenious or off the wall is welcome. I feel as if I am missing something here, albeit I feel as if I am on the tip of answer (tip of tongue).

Thanks again.
Fayt~

[faytmorgan]

Originally posted by DannytheRadomski:
The Ferrari F430 made a great sound. The reviews I've heard about the car make it sound a bit cold, but the exhaust note sounds incredible.

Love the sound, the car is junk in my opinion. As for design goes, I am a fan of the Honda engines personally. Honda went very far with mpg, reliability, handling etc with the nsx with just a sohc v6. They get around 31 mpg back in 2000. That is without direct ignition, direct injection, obd3 (which i guess is technically not out yet), electronic throttle body, and many other modern crap.

the 427 cobra wasn't taken down for the 0-60 game until 88(?). and that was just a small car and a big engine. and the car could handle.

i would take an nsx hands down over any Ferrari made in the last 25 years, put about 20k into it and blow the doors off (ferrari) and be able to do 200 plus mph.

but alas the sound of the ferrari cars are just amazing imho.

[Owen Thomas]

Is there a way, (dynamically) without raising temp per say, ... that one could increase the speed of sound?
Nope. You can increase the gas velocity by making the pipes more narrow, but the local speed of sound is described by gas properties and temperature. If you want to inject helium into your exhaust stream you could, but um, probably not worth it.

Just for clarity, a tri-y exhaust system is usually a 4-2-1 merge (three 'y' collectors), while the one you linked a picture of was a 4-1 merge collector. Also, what do you mean by a "180 degree header"? Do you mean pairing the primary collectors for 180* crank offset, or just a u-pipe?

[AxelRipper]

Well there's always this option (not sure if you posted in the OP... TL;DR.)

http://www.lingenfelter.com/LP...ce-Engine-Dyno-Video (http://www.lingenfelter.com/LPEforumfiles/showthread.php?904-More-Flat-Plane-Action-Lingenfelter-Race-Engine-Dyno-Video)

[faytmorgan]

Originally posted by Owen Thomas:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Is there a way, (dynamically) without raising temp per say, ... that one could increase the speed of sound?
Nope. You can increase the gas velocity by making the pipes more narrow, but the local speed of sound is described by gas properties and temperature. If you want to inject helium into your exhaust stream you could, but um, probably not worth it.

Just for clarity, a tri-y exhaust system is usually a 4-2-1 merge (three 'y' collectors), while the one you linked a picture of was a 4-1 merge collector. Also, what do you mean by a "180 degree header"? Do you mean pairing the primary collectors for 180* crank offset, or just a u-pipe? </div></BLOCKQUOTE>

180* offset, and there is more than one kind of tri-y but generally yes, 4-2-1.

[faytmorgan]

Originally posted by AxelRipper:
Well there's always this option (not sure if you posted in the OP... TL;DR.)

http://www.lingenfelter.com/LP...ce-Engine-Dyno-Video (http://www.lingenfelter.com/LPEforumfiles/showthread.php?904-More-Flat-Plane-Action-Lingenfelter-Race-Engine-Dyno-Video)

I did already say I will not be using a 180 crank for a myriad of reasons, also that is an ls1 motor in that link. I have a gen1 sbc. I am not a fan of the ls1 motor from personal experience. They had a great idea and screwed it up.

[Owen Thomas]

I am thinking that with a tri-y design and the proper length of the primaries and matching of course, that one could reproduce the 180 pulse.
This sounds to me like what you have called a 180 degree header. Using the exhaust pulse from another cylinder 180 degrees out of phase to scavenge is what you're talking about, right? Why is it that you don't want to use a 180 degree header?

[faytmorgan]

Originally posted by Owen Thomas:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I am thinking that with a tri-y design and the proper length of the primaries and matching of course, that one could reproduce the 180 pulse.
This sounds to me like what you have called a 180 degree header. Using the exhaust pulse from another cylinder 180 degrees out of phase to scavenge is what you're talking about, right? Why is it that you don't want to use a 180 degree header? </div></BLOCKQUOTE>

space constraints, heat, weight.

[Owen Thomas]

space constraints, heat, weight.
Well, those are always the restraints on an exhaust system... What I'm getting from this is that you want the effect of long pipes, but you don't want long pipes?

[faytmorgan]

Originally posted by Owen Thomas:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> space constraints, heat, weight.
Well, those are always the restraints on an exhaust system... What I'm getting from this is that you want the effect of long pipes, but you don't want long pipes? </div></BLOCKQUOTE>

That would be incorrect. I am after the aesthetic affect (the music created) that occurs when the puleses are spaces 180 degrees as per the ferrari toned exhaust caused by the 180 pulse.

180 headers are not only very very long but imagine having 8 pipes piped under or over the engine 1 and 5/8ths diameter about 30 or more inches long connecting the primaries that are 180 degrees (firing order wise) apart, then again another y to bring them from a 360 degree header to a 180 degree. THIS is a HUGE header.

so this is much more (size) than any other exhaust known. so the heat the space constraint etc was a valid response. Does this make sense?


also as a note in any other configuration that i am currently aware of shorter pipes = higher freq note (which is what i am after) and longer pipes produce a lower freq note.

[Owen Thomas]

The pipes should not need to be 30" long to pair with a 180 degree off cylinder, but yeah that would definitely make it more complicated. Especially with the 5-8 and 1-4 pairs you would have to do. Although, as a side note, that should get you a little more juice if you do it right.

The only other thing I can think of to increase the pitch using header design is to decrease diameter, but if you're already planning to run 1"5/8 on that size engine it's going to kill your power (probably). You could look into different types of resonators and megaphones to put on the secondaries, or experiment with that magic x-pipe. Having not played with any of these things myself, I can't really give any insight, but as usual the best thing you can do is test out different setups.

I'm sure there are lots of other ways to affect exhaust note, but unfortunately I think most of them would end up lowering the tone. Sorry I couldn't be of more help.

[Mbirt]

To eliminate the "American vs. European" issue, is it safe to say that this, http://www.youtube.com/watch?v=pdi8tHbmAdc, is the sound that you do not desire?

As you eluded to earlier, you cannot create frequency content that the engine does not produce. For 3000-7000 rpm, the firing frequency, the 4th order sound, will be 200-467 Hz. The exhaust sound will also contain frequencies higher and lower than this. Higher frequencies will come from the exhaust blowdown event and greater pressures will generally create more high-order noise. The most significant will likely be the 8th order, or double the firing frequency.

Lower frequencies, the ones you are trying to avoid, come from uneven mixing of pulses due to geometrical discontinuities in the exhaust ducts cylinder-to-cylinder and odd firing orders. For a cross-plane v8, this will usually be the 1.5 and 2.5 orders.

This video, http://www.youtube.com/watch?v=DnzxuS1HHpQ, has an interesting comparison between a C63 AMG and an M3 but with similar exhaust systems. The M3 has a higher-piched, raspy tone, while the C63 has more of the broad-range sound with more low-frequency content. The biggest difference I see between the cars is the log-style manifolds that come on the C63. Its uneven mixing of pulses creates odd-order sound and steals energy from the 4th order to do so.

My advice would be this:
-Don't skimp on the headers. Equal length will yield the least half-order sound.
-Use an X-pipe or merge into a Y.
-Keep it symmetrical
-Long, uninterrupted pipes to the muffler(s) at the end of the system. The Innotec M3 system gets its rasp from this.
-Corsa RSC (sounds great on E92 M3's) or one of the short-length Dynomax VT mufflers. The Corsa muffler kills the lowest frequencies with quarter-wave tuning, while the VT has a passive flapper valve for low frequency control. The flapper snaps open quickly at medium flow rates. The longer-length versions will contain more fiberglass, which might kill the character you desire to create.
-Early exhaust valve opening to allow the sound wave to steep-front and create the raspiness that seems to help the M3 (with the right exhaust) sound like your ideal cross-plane v8.

I've got a few FFT and sound analysis apps on my phone I like to play with. It was interesting comparing the C63 to the M3 in the video above when they switched from car to car. You might get a kick out of doing some quick analysis of exhaust sounds that you do and do not like. Being able to quantify the sounds with frequencies will help you decide which tuning elements to use.

[faytmorgan]

Originally posted by Owen Thomas:
The pipes should not need to be 30" long to pair with a 180 degree off cylinder, but yeah that would definitely make it more complicated. Especially with the 5-8 and 1-4 pairs you would have to do. Although, as a side note, that should get you a little more juice if you do it right.

The only other thing I can think of to increase the pitch using header design is to decrease diameter, but if you're already planning to run 1"5/8 on that size engine it's going to kill your power (probably). You could look into different types of resonators and megaphones to put on the secondaries, or experiment with that magic x-pipe. Having not played with any of these things myself, I can't really give any insight, but as usual the best thing you can do is test out different setups.

I'm sure there are lots of other ways to affect exhaust note, but unfortunately I think most of them would end up lowering the tone. Sorry I couldn't be of more help.

the 1 and 5/8ths dia is the correct dia for this size motor and rpm range. the 30 inches would be so the primaries stay equal length which is very important.

[faytmorgan]

Originally posted by Mbirt:
To eliminate the "American vs. European" issue, is it safe to say that this, http://www.youtube.com/watch?v=pdi8tHbmAdc, is the sound that you do not desire?

As you eluded to earlier, you cannot create frequency content that the engine does not produce. For 3000-7000 rpm, the firing frequency, the 4th order sound, will be 200-467 Hz. The exhaust sound will also contain frequencies higher and lower than this. Higher frequencies will come from the exhaust blowdown event and greater pressures will generally create more high-order noise. The most significant will likely be the 8th order, or double the firing frequency.

Lower frequencies, the ones you are trying to avoid, come from uneven mixing of pulses due to geometrical discontinuities in the exhaust ducts cylinder-to-cylinder and odd firing orders. For a cross-plane v8, this will usually be the 1.5 and 2.5 orders.

This video, http://www.youtube.com/watch?v=DnzxuS1HHpQ, has an interesting comparison between a C63 AMG and an M3 but with similar exhaust systems. The M3 has a higher-piched, raspy tone, while the C63 has more of the broad-range sound with more low-frequency content. The biggest difference I see between the cars is the log-style manifolds that come on the C63. Its uneven mixing of pulses creates odd-order sound and steals energy from the 4th order to do so.

My advice would be this:
-Don't skimp on the headers. Equal length will yield the least half-order sound.
-Use an X-pipe or merge into a Y.
-Keep it symmetrical
-Long, uninterrupted pipes to the muffler(s) at the end of the system. The Innotec M3 system gets its rasp from this.
-Corsa RSC (sounds great on E92 M3's) or one of the short-length Dynomax VT mufflers. The Corsa muffler kills the lowest frequencies with quarter-wave tuning, while the VT has a passive flapper valve for low frequency control. The flapper snaps open quickly at medium flow rates. The longer-length versions will contain more fiberglass, which might kill the character you desire to create.
-Early exhaust valve opening to allow the sound wave to steep-front and create the raspiness that seems to help the M3 (with the right exhaust) sound like your ideal cross-plane v8.

I've got a few FFT and sound analysis apps on my phone I like to play with. It was interesting comparing the C63 to the M3 in the video above when they switched from car to car. You might get a kick out of doing some quick analysis of exhaust sounds that you do and do not like. Being able to quantify the sounds with frequencies will help you decide which tuning elements to use.

One thing i find odd is the ipe f1 exhaust is SOOO high pitched in comparison to many other systems and even more so from their factory headers as I have posted in my original post. in reference to the s65 bmw.

they achieve this sound without the use of any special ignition system or a 180 header.

[faytmorgan]

also the c63 is a 6208 cc motor whilst the m3 is a 4.0lt

[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.

[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: http://www.southerncarparts.com/images/Corsa%20C5%20Extreme%20Exhaust.jpg

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 (http://i938.photobucket.com/albums/ad226/faytmorgan/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

[faytmorgan]

http://www.corvettefever.com/t...install/viewall.html (http://www.corvettefever.com/techarticles/corp_0710_c6_corvette_exhaust_install/viewall.html)

[Mbirt]

Ah, that stock C6 muffler looks familiar. I worked in the department that designed it http://fsae.com/groupee_common/emoticons/icon_cool.gif

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 (http://www.arkperformance.com/SearchResults.asp?Cat=13)

[faytmorgan]

Originally posted by Mbirt:
Ah, that stock C6 muffler looks familiar. I worked in the department that designed it http://fsae.com/groupee_common/emoticons/icon_cool.gif

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 (http://www.public.iastate.edu/%7Eadambomb/intake_WOT_specgram.wmv)

[englertracing]

http://www.youtube.com/watch?v=ZcAQrHPHy98&feature=share&list=UUUevkYupggcQby5kQlGZACA

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?

[Charles Kaneb]

An American V8 has a 0-180-90-270 or 0-180-270-90 crank. If you use a 4-1 pipe with roughly equal header lengths on each side, you get the Detroit Rumble, with uneven spacing between exhaust valve opening "hits" on each side.

If you want it to sound like a Ferrari V8, you need to get the pulses to show up at the same time they do on a Ferrari V8.

A Ferrari V8 uses a 0-180-180-0 crank. You'll need to fake this. Fortunately, you have one cylinder firing every 90 degrees just like the Ferrari, so you need to link 'em that way.

An LS1 has a 18726543 firing order, with 1357 and 2468 on each bank. The exhaust pulse order you have right now is 1753 and 8264. To get what you want, you need to cross over some pipes so you're running 1764 down one pipe and 8253 down the other. You will need to get the primary lengths on each header to be the same.

Good luck.

If all else fails, build a set of very short equal length headers terminating in the hotside intake of a pair of turbochargers. Turbochevys are awesome.

[jlangholzj]

one thing I've always been a sucker for is the subaru grumble.

http://youtu.be/pLNUV6Ch97c?t=1m8s

I think mine's getting a COBB stage 1 tune plus intake and exhaust within the first few paychecks. Gotta hear that girl talk!