Sound and Energy loss.

[OBEEWON]

Sound is energy.

If sound is energy, then deductively the sound of a car = loss of energy.

I was riding in Smelly240's car the other day, which is very fast, and I was marvelling at how quiet it was. I tried to talk to him about energy lost through sound but he just laughed "OK my car is fast because its quiet." lol

Another car I saw ( I cant remember the name of the owner) A black Kouki with an RB25 that competed in Nopi drift. I was always amazed at how quiet the car was EVEN with a straight side exit with no mufflers. The car made over 700whp and all you could hear was turbo spool.

So my question is:

How can you make your car more efficient by muffling the sound (without stifling exhaust flow of course for forced induction cars)?

Has anyone contiously tried to achieve something like this?

[murda-c]

The most powerful car i've ever seen was also the loudest.

soooo i think you're wrong. haha

[smelly240]

:P

mines quiet bc the turbo is so huge i think.

with the HX35 it was a lot louder.. im goin back to it tho - since i broke too much stuff at 30psi on the big one.

[sqd]

I have to say mine is very quiet aswell. 400 hp at the crank, top mount 58mm turbo, Invidia 3" DP, decat and a 3" Nismo catback.

[OBEEWON]

The turbo definitely has alot to do with it. That RB25 Kouki that was DEAD silent was running some HUGE turbo I forget what it was.

The most powerful car i've ever seen was also the loudest.

soooo i think you're wrong. haha

LOL, I think you mistake what I'm saying. What Im thinking is, that car that you saw that was so loud, could be a bit more efficient if it could use the energy it is losing through sound.

Im not saying loud cars can't be powerful, or powerful cars can't be loud cuz clearly thats not true.

Steve I wish you dyno'd that car or took it down the quarter before you switched back.

[clark]

Sound is energy.

If sound is energy, then deductively the sound of a car = loss of energy.

I was riding in Smelly240's car the other day, which is very fast, and I was marvelling at how quiet it was. I tried to talk to him about energy lost through sound but he just laughed "OK my car is fast because its quiet." lol

Another car I saw ( I cant remember the name of the owner) A black Kouki with an RB25 that competed in Nopi drift. I was always amazed at how quiet the car was EVEN with a straight side exit with no mufflers. The car made over 700whp and all you could hear was turbo spool.

So my question is:

How can you make your car more efficient by muffling the sound (without stifling exhaust flow of course for forced induction cars)?

Has anyone contiously tried to achieve something like this?

does smelly 240 have the stock exhaust mani? i noticed when i switched from an aftermarket tubular mani back to the stock mani, my exhaust was much quieter.

also, i was watching this show GearZ on speedvision and they took a vette and added two turbos to where the mufflers are located. the car no longer needed mufflers because the turbos quieted the exhaust down.

soooo i guess a big turbo can do a nice job of quieting down exiting exhaust.

[GunmetalSR]

:P

mines quiet bc the turbo is so huge i think.

with the HX35 it was a lot louder.. im goin back to it tho - since i broke too much stuff at 30psi on the big one.
wat are u runnin now thats bigger than the hx35 if u dont mind me askin

[garagelu]

a lot of high horsepower cars run external dump too. External dump=not quiet.

But yea I agree, big turbos with rerouted dump seems to be pretty clean sounding. And inline 6 cars sound great in general. Big turbo sr's are still pretty loud imo.

[blueshark123]

i think this is irrelevant and wont make any diffrence at all if car is loud or not

[OBEEWON]

http://img200.imageshack.us/img200/506/0910091738.jpg

I hope Stinkey dont mind. You gotta get the exact specs from him. It weights like 44lbs I think. Huge.

[GunmetalSR]

http://img200.imageshack.us/img200/506/0910091738.jpg

I hope Stinkey dont mind. You gotta get the exact specs from him. It weights like 44lbs I think. Huge.
that bitch is huge
ive never seen a mani like that on an sr, custom?

[OBEEWON]

Yeah, he made it. Basically an up-pipe to relocate the turbo. I dont have a picture of the of the hotside but it massive. VGT.

[GunmetalSR]

thats sick
anyways do u think its louder or quieter if its more restrictive
bc if its less restrictive but louder then i think u would make more power a little quicker

[OBEEWON]

Well in comparison to his HX35 this thing makes power about 500rpm later. At least it feels that way to me. But it makes WAY more power. Spinning the middle of third. He broke his trans and diff with this turbo. But it is as he said significantly quieter, even at WOT.

The 35 wasn't crazy loud, but compared to my 2871r it is pretty quiet.

[slider2828]

Sound has nothing to do with power as it is just resonance in chamber due to flow, but doesn't have anything to do with energy....

[OBEEWON]

Sound has nothing to do with power as it is just resonance in chamber due to flow, but doesn't have anything to do with energy....

LOL,You sure about that?


Heat and sound are the most common ways that energy is lost in a mechanical system.

It's an established fact that sound is energy, so we can't really debate that aspect of the subject.

Im not really asking about a theory. I just want to know what people have done to maximize efficiency while minimizing sound.

[ryguy]

If the sound were coming from friction, you might have a point, but in an engine, sound is coming from ignition of fuel. There's no way to physically quiet the ignition itself. Top Fuel dragsters aren't very quiet, nor are fighter jets.

[slider2828]

ryguy, put it better.... this sound is not from friction but rather from the combustion chamber of the engine.... I think flow will change the resonance of sound so it depends lol....

[xpertsnowcarver]

I would assume (since a few aftermarket companies like AEM and A'pexi work on this) its not so much how loud or quiet the sound is, but whether there is harmonic resonance to make the flow of air or exhaust smoother. I'm not big on this subject, but AEM had (or still has) this huge thing about the engine making a certain pitch/tone that causes a harmonic vibration in the intake pipe to make the air flow more smoothly into the engine. The same could be done for the exhaust if enough engineering is put into it.

[jspaeth]

I would assume (since a few aftermarket companies like AEM and A'pexi work on this) its not so much how loud or quiet the sound is, but whether there is harmonic resonance to make the flow of air or exhaust smoother. I'm not big on this subject, but AEM had (or still has) this huge thing about the engine making a certain pitch/tone that causes a harmonic vibration in the intake pipe to make the air flow more smoothly into the engine. The same could be done for the exhaust if enough engineering is put into it.


This is exactly correct.....reducing shock waves and trying to keep losses due to turbulance to a minimum can increase efficiency.

[TIG]

I would assume (since a few aftermarket companies like AEM and A'pexi work on this) its not so much how loud or quiet the sound is, but whether there is harmonic resonance to make the flow of air or exhaust smoother. I'm not big on this subject, but AEM had (or still has) this huge thing about the engine making a certain pitch/tone that causes a harmonic vibration in the intake pipe to make the air flow more smoothly into the engine. The same could be done for the exhaust if enough engineering is put into it.

Good points, but keep in mind that a well tuned exhaust system is part of the entire air induction system. In other words, designing a proper intake manifold and exhaust system to get them to work in harmony is key to optimal scavenging.

[rc1honda]

I really don;t have much to add other then a buddie of mine put a brand new 605ci big block in his car. And compared with his other motor a 383ci w/ spray it was much quieter while still making close to 900hp.

I was amazed at the track and kept asking him why it was so quiet. I was watching other cars there running 11's and 12's that sounded way meaner. His car was running 9's and purred like a kitten. I know exhaust has a lot to do with sound, but he only had a resonator on each pipe and it was still real quiet. I thought a 605ci motor would sound like a freakin train insted it sounded like a ford GT or something.

I don't know anything about maximizing power through sound but i thought i would share.

[svensko]

You should make your exhaust dump into your intake. This way all of the noise (energy) lost through the exhaust will be reused and efficiency will go up greatly.









Just kidding.

[xpertsnowcarver]

^^Super EGR system ;)

[tt99ol]

think of it this way
a muffler absorbs the sound energy
thats why it makes things quiet
you would need something that goes in place of a muffler then converts sound into some other kind of energy
or just put a bunch of turbos on until its silent
then run 150psi of boost

lol

[svensko]

I doubt the energy lost through noise is enough to justify a way to recoup it (besides a turbo). If noise was that large of a loss of energy, I'd think the pro-stockers would have figured out a way to harness it by now.

Surely the pro-stockers don't make their cars so loud to just keep the rednecks in the audience happy... or do they? :naughtyd:

[tt99ol]

actually the noise
but mostly airflow of the exhaust
is used for downforce
thats why the headers point up

[jspaeth]

You can't recapture the sound and convert it to energy.

Only in some cases is sound really wasted energy:

If something is resonating (metal in a pipe) for example just due to it's inherent natural frequencies, then there's nothing you can do really.


If your exhaust or intake is super loud to resonation, shockwaves, too much turbulence, that is an inefficiency you can actually try to eliminate to see a real difference.

So it depends upon WHAT noise you are talking about.

[ryguy]

Remember too that V8 cars running dual 2.5" exhausts will have less "resonance" than a single 3" exhaust.

[jspaeth]

Remember too that V8 cars running dual 2.5" exhausts will have less "resonance" than a single 3" exhaust.

Yes! You split the flowrate into 2 channels of that cross-sectional area, and the average velocity is substantially lower, less turbulant flow!