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I've got resonator tips on my stock mufflers and I reeeeeally like the stock tone. I just wish it was louder. That's all.
Short of a muffler delete, can the stock muffler be opened and reamed out a little bit? I know there was a guy who opened one up. Whoever you are, can you chime in?
i can easily get my hands on a welder and stuff and surgically remove parts of the muffler if that will ultimately get me the sound I want.
Have you tryied driving around with the mufflers disconnected? I would recommend this first. In truth, if I knew how to mod the mufflers correctly, I would have done that. When I opened them up I didnt know I would need an air hammer and kind of ruined them. Now I know how they are built so it'd be easier to mod them.
Basically you have three ways of modding the stock muffler, but it can be a lot of work. You will need a powerful cutting disc to cut through the two layers (one thin, one very thick) of steel casing, and maybe a couple of these discs. Be careful with rust from a health stand point as well as physically not being able to weld extreme rust.
Option 1: Modifying section I. Cut out a square above this chamber, and block off the end of this pipe by welding a small square or circle metal plate. This will force air to accelerate faster through the holes in chamber II. Weld square on top back up. Basically, quicker response, slightly louder because sound is not being canceled in chamber I, but is still in chambers II and III.
Option 2: Modifying section II. Same as before, cut out a square. Cut out pipe in chamber II completely. Block off the hole with a piece of metal going into chamber I. This will allow alot more flow. Tiny bit louder than option 1.
Option 3: Modding section III. Cut out chamber III's pipe completely. Block off both sections where it would go into chamber II. This will be overall the loudest, flow the best, and is what I would have gone for. I can still suspect almost no drone with any of these.
Or, what if I open chamber III and just drill some holes into the input pipe, so it's a semi-bypass? That would be easiest and take me twenty minutes tops.
Yes, and I have a diagram of where newer GS mufflers are designed like this.
The pipe connected to the tailpipe tip is kindof like a glasspack so you get roughly the same sound, but less noise cancellation. It would only cancel a little in chamber III.
Sound physics are weird though, I say it shouldnt drone though because these mufflers are so heavy, they absorb and dampen alot of resonance. Especially so at a crucial part of the system, at the end of the exhaust.
Well if you did that to section III, it still has all those exhaust pulses still emptying into the other chambers. You could do it but I think it would have little to no sound effect outside the car or especially inside
Air needs to be guided or else it will take almost all paths of resistance in contrast to the least. Its also worth noting that chambers III short pipe is wrapped in the same glasspack material as the longer one, so drilling could get messy.
Yeah these are built well so a little difficult to make loud. I feel like they do shift the power band down for sure for maybe a loss in the top end. I think you would see this more in the I6 vs the V8 though, and even less apparent in modded ones. The overall design is a little restrictive.
If I understand the Helmholtz design right, the first chamber is where the cancellation all happens. The first chamber inverts the sound wave and sends it right back into the exhaust, where it goes through chambers two and three and out. If that's the case, wouldn't simply blocking chamber one boost the volume a noticeable amount by eliminating the cancellation?
Well chamber one takes alot of engine breath to fill it up. Some pulses are cancelled by hitting each other in that chamber. Others are cancelled in chambers one and two, and many combinations of all chambers. Blocking off chamber one will make things go a bit faster, but not make things much louder. You are changing a small piece of the puzzle, probably not enough to notice, maybe in throttle response.
I thought about cutting the output pipe in chamber two as well but still slightly object to it just for all the reasons above.
Thats why theres so much thought that goes into performance headers, exhaust, porting, etc. it all adds up
The cats probably absorb 10 percent sound, the third cat 10 the stock torpedo resonators absorb probably 60 percent of sound and the mufflers the other 20.
Yeah because you will basically be letting less bass mids and treb cancelled out. You could also try just cutting both output sections in the chamber one and two. I dont know if it will be worth it, and will boost treble more than any of the mods mentioned before. I dont think it will flow as good as option 3 but I dont really care for the stock sound so I would like to see anything done. Although I cant say anything other than option 3 would be worth it to me personally.
Ooh cutting an output pipe hole in chamber 1 would effectively eliminate that main cancelation, plus flow would have a way out at both ends of the muffler. Didn't think about that. And if it were a small hole, cancellation would be reduced and backpressure would stay about the same.
01-27-17, 09:01 PM
Stock exhaust tone, only louder?
