weaz4200

iTrader: (2)

I was curious what determines the exhaust sound? Every vid ive seen of one brand of muffler/exhaust sounds different on every car.... Here are a few vids of what sound id like to get when i get around to the exhaust..... the first you could here right off the bat what i mean as soon as he accelerates... http://www.youtube.com/watch?v=DS0D7LhoVjs. This second one starts at 1:20 into the vid.... http://www.youtube.com/watch?v=PSJ-AwBYBJI .. Heres the last... This last one just sounds sick. Just has a little more treble sound to it, which i dont want ... http://www.youtube.com/watch?v=H4c21_HO0PE. The only way that i could describe it is that it has somewhat of a demonic sound to it... I know a lot of mufflers sound good at idle but as soon as you punch the gas is just sounds like crap... Id like the mufflers/exhaust to maintain the sound at idle, through higher RPM's...

weaz4200

iTrader: (2)

Anyone know the answer to my question??? Im trying to find out what internals in the engine, as well as power adders contribute or alter exhaust sound. I dont get why companies put up vids of their exhaust sound when it wont even sound like that on other cars, unless its another one of the same exact car (N that might not even be the case)... If 2 guys both have the same exact exhaust on their cars they wont sound identical, so im curious what is the determining factor?

Rolling Thunder

There are many factors of the motor itself which will effect sound. The one in particular that most people notice immediately is the cam for example a small cam will generally have a nice smooth idle where a big cam will have that lopey race car unevenness too it. Although everything right down to the compression ratio will effect the sound somewhat. What type of construction the muffler is will give a general idea of what a motor will sound like but thats about it. Although keep in mind online sound clips are terrable representations of what a car actually sounds like. Not only is the quality of the recording almost always lacking but the distortion is terrible. Also "clipping" of the sound is a big problem with loud exhausts as the sound emitted is louder then they can record.

weaz4200

iTrader: (2)

I understand that a lot of recordings sound crappy, thats not what i was referring to... Ill see if i can explain my point (what im looking for) using a few examples.... X-Ravin just posted a thread, which contains this link, ill use it as an example.... http://smg.photobucket.com/albums/v2...TAwithGMMG.flv 28 seconds into the clip the guy hits the gas then lets off of it, and as the RPM's drop you hear an example of what im talking about... Dont know what words to describe it but it sounds choppy, restricted, clogged....

Thats one example... heres another... One of the links i posted earlier... http://www.youtube.com/watch?v=H4c21_HO0PE .... This one sounds pretty good at first, then around 8 seconds in he lets off the gas, n around 8 1/2 to 9 seconds, theres that sound again...whats making that sound.. its annoying....

Heres another thing, that pypes violator muffler, they have a 2 videos on their site, one is the previous one i just posted this is the other.... http://www.youtube.com/watch?v=k2Cq84fzkZY&feature=player_embedded both second gen Camaros... The recording of the red one is crappy, ill give you that. But that muffler doesnt even come close to sounding similar... The 81 sounds 10x's better than the 78... THats what im curious about.... Id like to know what muffler is going to sound good reving and dropping idle... I mean who has money to mess around with 2,3, or even 4 different mufflers ....

So the cam, the constrution, and even the compression you say.... Cau you elaborate a little, So say the compression has an effect, whats a 10.5:1 gonna do vs an 8.5:1....Sound wise??? I know the cam gives it a smoother vs choppy idle, is that it, or does it effect thickness of sound, how smooth it flows, no rectricted sound either...

Rolling Thunder

Ok well lets see if i can clear this up a bit as best i can anyways. In the first clip when he eases off the pedal all motors sound like that some mufflers may accentuate it more or have more of a popping sound to it but i find they all have that sound. Scientifically although this is just a educated guess what i think its related too to the fact when thats happening the motor is choked off. The motors is being reved up way high and then the carb or throttle body (the motors only source of air) is closed. The sheer momentum of the motor is what allows the motor to spin at the higher RPM despite the fact that the air being supplied isn't sufficient. As result the motor winds down but in the mean time the cylinders will not be filled with nearly as much air fuel mixture as it was at full throttle causing a weaker burn. Now for the second set of videos although those cars supposedly have the same basic exhaust system alot of details are missing. The one big piece is do they have headers? Headers will give a much louder and more of a thunderous sound or rumble depending on the muffler. Another huge deal even more significant than the headers is the catalytic converter. It sounds like the louder one has no cat or at least a high flow cat where as the quieter one probably has a regular replacement. As far as the effect of the things like cams or compression its all really relative to other parts. For example increasing the compression on a motor with a big cam would not have the same effect as a car with a small cam. Generally speaking increasing compression it will tend to make it a little louder with a sharper sound but thats only one small piece of the puzzle. Everything right down to the ignition timing changes the sound somewhat so its really hard to create a certain sound. The cam dosnt really change the sound so much other than the idle from what i can tell but its not just that it sounds rougher ( i mean it does but its not like its just a missfire) but the whole sound is different. Its hard to attribute whats the causes the resulting sound if its the roughness or is it the fact the large duration causes the exhaust valve to open sooner while the gasses are still burning but its got a unique sound that can only be describes as "lopey".

weaz4200

iTrader: (2)

Thanks for the detailed reply... As for the motor not getting as much air, and the motor is choked off... Do you think theres a way to address that issue, if that is in fact the case, or is it inevitable? OR do you think that if, say the compression was lower,since the motor then doesnt require an extreme amount of air/fuel, like say a high compression motor...the unburnt mixture wouldnt be that big (air vs fuel), and the cause of the exhaust sound wouldnt be so drastic, or vise versa (high compression)?... Ill throw so more questions at ya later... for now im out... Peace... Thanks again...

Rolling Thunder

Well Im thinking its pretty much the nature of the beast kinda problem. Or at least i don't know of a solution. Your best bet would be to try and get a muffler that minimized the sound but I think pretty much every aftermarket muffler will give it that sound to one degree or another which would be a good deal more noticeable than stock. I get what your saying about lowering the compression but the thing is the fact that the carb or TB is closed and the resulting pressure differential is what slows the motor down. Changing the compression would still result in the same pressure for the most part but may affect the time it takes to go from 5k to idle.