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 engine - Wikipedia, the free encyclopedia
http://cars-database.com/data_...8/maserati-v8-03.jpg
a similar snarl that the Corsa gives the Domestic V8
http://www.youtube.com/watch?v=Un_sQtJA2iA]Maserati GranTurismo Exhaust Note! - YouTube
http://www.atzonline.com/index...2a814fd6b316776454]A New V8 Engine Powers the Maserati GranTurismo S - ATZ online
x pipe
http://www.ebay.com/itm/08-Mas...590912#vi-content]08 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
same 136 engine only the tipo f136 has a flat plane.
http://www.youtube.com/watch?v=gwVlcgSUO0A]Ferrari 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 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 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 M3 Exhaust Compilation - YouTube

and lastly compare those to this
http://www.youtube.com/watch?v...&feature=related]E92 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 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://www.epi-eng.com/piston_...chnology.htm]Exhaust System Technology: Science and Implementation of High Performance Exhaust Systems

http://www.billswebspace.com/D...austDesignReview.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://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

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 resonance - Wikipedia, the free encyclopedia

In use on an exhaust system
http://forum.grrrr8.net/showthread.php?t=10801]Capped 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 Mufflers
corsa cut away
http://s938.beta.photobucket.c....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 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

[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

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.