Muffler Design Question

[laxman851]

To preface, this question is geared more towards the construction of mufflers. Does anyone know the "design" of the mufflers used in the more common cat-back options for our cars? Ie: Awe/autospeed/apr/borla ect. I'm trying to gain a further understanding as well as comparison between the mufflers; performances, theories and sound properties.

thanks

[laxman851]

... or if anyone knows where these companies outsource their products from that may help.

[omgwtfbbq!]

They are back pressure type mufflers. They partially reflect the wave energy back onto itself to cancel out certain frequencies. They also force the waves through spaces smaller than the amplitude of the wave, which decreases the energy through friction.

[mufflerman]

I think someone above thinks they work for NASA!

To answer your question with useful information, all of the brands you mention use a straight through design core. Basically you can roll a golf ball through any of them. They deaden sound by absorbing it through perforation in the core of the muffler.

[lbs4]

^^ someone thinks there a muffler tech! but that sounds about right.

[omgwtfbbq!]

I think someone above thinks they work for NASA!

To answer your question with useful information, all of the brands you mention use a straight through design core. Basically you can roll a golf ball through any of them. They deaden sound by absorbing it through perforation in the core of the muffler.

Are they absorption type mufflers? My borla mufflers didn't seem to be straight through but I never really took a good look at them.

Either way the second half of my post stands with absorption type mufflers, they use packed material to create the holes for wave friction on top of using the actual holes themselves.

[laxman851]

To answer your question with useful information, all of the brands you mention use a straight through design core. Basically you can roll a golf ball through any of them. They deaden sound by absorbing it through perforation in the core of the muffler.

Either way the second half of my post stands with absorption type mufflers, they use packed material to create the holes for wave friction on top of using the actual holes themselves.

Well thank you both for the responses, I wasn't really sure if they were chambered or not.

Since straight through design has been established, i'll move on to my second question. I'm exploring my options for assembling my own exhaust "system". I figured before I even try dealing with fitments I might as well see if there is an innate design flaw or setback with the type of mufflers I plan on using. I found a muffler that is a dual inlet/outlet using 3inches in a "straight through design" although it's misleading because I found that it's not quite straight through. That particular muffler incorporates an x-pipe and I'm wondering if it will create so much turbulence and/or back pressure that it could negate the benefits of having a true dual 3inch exhaust.

[mufflerman]

This is my car with our custom made dual 2.5" an xpipe and magnapacks.

http://m.youtube.com/index?desktop_uri=%2F&gl=US#/home

[GunSupplier]

This is my car with our custom made dual 2.5" an xpipe and magnapacks.

It is?

Looks more like "HDStarcraft teaches TimothyDeLaGhetto2 how to play StarCraft 2"

Haha.

[Dubluv11]

It is?

Looks more like "HDStarcraft teaches TimothyDeLaGhetto2 how to play StarCraft 2"

Haha.

bahaha

[megafreakindeth]

You need the two exhaust banks to merge or else the motor wont run right/as efficiently. it will cause the more dominant side to pull the intake air away from the less dominant side. You can tune this out and thats how race cars get away with it but for a street car youll need to merge the exhaust at the first muffler to have an effectively balanced exhaust.

straight through mufflers come in two basic varieties. The most common/least restrictive design is a smooth perforated pipe surrounded by stainless steel baffleing. this offers the least sound deadening though. The other design is a scalloped tube which has the perforations in the center pipe protuding into the exhaust flow, this is quieter but more restrictive.

A baffled muffler can have empty chambers that never connect back to the main exhaust flow, this is the quietest and hardest to design because it really depends on the particular engine. Its the design the factory uses and probably spent a million dollars designing.

The other design is baffled but allows all the air to eventually leave with the main flow(edlebrock sdk or something like that is the best example i can think of). This is like what omgwtfbbq! was saying where the muffler redirects certain harmonics and then reintroduces them back to the exhaust at a later time to cancel out 'noise'. Since dual 3in exhaust is overkill anyways it wouldnt hurt to use a baffled muffler because youll have so little backpressure, adding some will help more than hurt. And it will keep things quieter. If i were to build my own exhaust I would put a baffled muffler as the first muffler and retain a straight through muffler for the rear muffler.