Exhaust with no drone?

lovelessjl · February 5, 2016

I recently bought a RCSB with the 5.3. I was looking for just a little noise with out creating a lot of noise inside. I found a good deal on a MBRP 3" exhaust "slightly used" so I figured I'd give it a shot. I'm glad I did, hardest part of the install was removing the factory exhaust. The exhaust fits great, and the sound is perfect. Under acceleration, it's got a great roar to it, but at idle it's a pleasant low rumble that I can just barely hear while in the truck. On the highway, I can just barely hear it, no loud drone or noise at all (I've never heard my truck on the highway from outside the cab, so who knows or cares what everyone else hears). I couldn't be happier with it.

Sierra Jon · February 5, 2016

With a fairly strong understanding of sound resonance, flow regimes and all that jazz, I looked into the flow mechanics of the GM Borla system and there IS significant effect from relocating the "flapper valve" upstream of the muffler. The stock muffler is actually fairly free flowing however, it creates turbulent or "dirty" flow downstream which the flapper valve helps to smooth out and is cleaned up by the resonator. Now, from what I can tell, and I used software that certainly wasn't designed for this application, but still similar, having the flapper valve upstream of an even MORE free flowing system helps to smooth the flow and control the velocity BEFORE it has a chance to become turbulent and create vibration, which in turn creates unwanted noise. Hence why Dynomax attempted to create a similar effect inside their VT muffler. I think I'm going to try an oval Magnaflow WITHOUT the resonator but moving the flapper valve upstream of the muffler. My goal is mimic the outcome of the GM Borla system. I want noise when I'm to the wood, wanna hear it idle, but don't want to hear a steady subwoofer racket on the freeway. I'm not overly worried about V4 mode as my truck is lifted 7" on 35's and, well, pretty much never sees V4 as a result. If anyone would like to suggest a Magnaflow that would be best, I'll give it a try and report back and try and use instrumentation during a video to produce real, measurable outcomes. I will be installing V-band flanges up and downstream of the muffler so I can install different mufflers to experiment. This venture will be subsidized by a local outfitter who wishes to be able to better tailor what its customers get. Meaning, they get a LOT of guys/gals coming through their doors every day asking for the same things as many of you, myself included, but don't want to shell out $1k+ for a catback system. So, we're going to try these theories out with about 4-5 different mufflers and record the results on video as well as with sound metering equipment for some unbiased results.

So I am trying to mimic a Borla GM exhaust as well. The muffler I picked out is the Borla ProXS 40359. This is suggested for the 2014 5.3lt on Borla's website. Would love to hear the difference of moving the flapper before the muffler. My plan was to just do a muffler swap first then delete the resonator after if it was too quiet. Was planning on leaving the valve no matter what as right now I have it pinned open anyway. That way I can pull the pin on the valve when I'm towing my camper.

Please let us know if you made any headway!

Thanks,

Jon

GMC_SD_Ult_16 · January 21, 2017

Reviving an old thread... I have a 6.2L..tried the muffler delete and it sounds good but too loud for me and the neighborhood. Resonator and flapper are still installed but the flapper rattles and I have had to clamp open. I have 3.5 inch exhaust. What 22" Magna flow exhaust can I get that will fit... I need a sound reduction but still want some rumble (assuming with sound reduction v4 will decrease as well)... Any help is appreciated... Planning to remove resonator and flapper if find the right muffler. I have an AFE Momentum GT CAI installed and am sure this has added to the sound increase as well. Thanks in advance.

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SirManny · January 21, 2017

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Edited January 21, 2017 by SirManny

Horacio · January 21, 2017

I just found a GM Performance exhaust tonight while trolling around on the net. I didn't get a chance to research it or know anything about it. Maybe you might want to look into it or maybe someone here knows.

GM part # 23462043.

I'm sort of looking for another exhaust system. My Corsa is loud upon startup and I'm sure about 5 of my closest neighbors don't appreciate it, not to mention I can't touch the accelerator until I get out of my gated community. I really don't want to put the stock exhaust back on it BC it's just as quiet as a Prius. The Corsa is great on the freeway for those times when you get a sleeper in the fast lane holding up the flow of traffic. When they finally move over I roar right past them and wake 'em up!

Krusty · April 8, 2017

Reviving an old thread... I have a 6.2L..tried the muffler delete and it sounds good but too loud for me and the neighborhood. Resonator and flapper are still installed but the flapper rattles and I have had to clamp open. I have 3.5 inch exhaust. What 22" Magna flow exhaust can I get that will fit... I need a sound reduction but still want some rumble (assuming with sound reduction v4 will decrease as well)... Any help is appreciated... Planning to remove resonator and flapper if find the right muffler. I have an AFE Momentum GT CAI installed and am sure this has added to the sound increase as well. Thanks in advance.

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Did you get a muffler installed?

https://www.magnaflow.com/products?partNumber=12909#modal-compatiblevehicles

GMC_SD_Ult_16 · April 8, 2017

Did you get a muffler installed?

https://www.magnaflow.com/products?partNumber=12909#modal-compatiblevehicles

Yes. 12909 Magnaflow.. I am happy with the results. Very little sound when cruising. Not super loud but better than stock on start up. When I give it the gas it sounds great. Super satisfied. I found since I did both the afe and the muffler the system seems way more responsive and is much more pleasurable to drive.

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powerhaulic · April 17, 2017

Yes. 12909 Magnaflow.. I am happy with the results. Very little sound when cruising. Not super loud but better than stock on start up. When I give it the gas it sounds great. Super satisfied. I found since I did both the afe and the muffler the system seems way more responsive and is much more pleasurable to drive.

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Same muffler here, all 3.5" tubing, no res, no flapper, 4.5" tip I think it sounds fantastic.

I also tow a 9000# camper long distance, not annoying in the least even towing.

I also believe there is an increase in response, I have an intake tube as well.

Did you replace entire tail? or leave the restrictions in place?......lol

GMC_SD_Ult_16 · April 17, 2017

Same muffler here, all 3.5" tubing, no res, no flapper, 4.5" tip I think it sounds fantastic.

I also tow a 9000# camper long distance, not annoying in the least even towing.

I also believe there is an increase in response, I have an intake tube as well.

Did you replace entire tail? or leave the restrictions in place?......lol

I replaced the entire tail and installed and AFE cold air Intake. Response has been improved to me.

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powerhaulic · April 17, 2017

I replaced the entire tail and installed and AFE cold air Intake. Response has been improved to me.

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Agreed!

Edited April 17, 2017 by powerhaulic

NorCalSLT · April 17, 2017

Corsa Touring or Sport exhausts.

mayfieldjeff · September 22, 2017

I think i am now committing to the Magnaflow 12909 to replace the stock muffler and flapper valve but leaving the resonator on. i was also planning on installing an Airaid Jr MIT with an AFE dry filter, keeping the stock Intake box. Does anyone have the part number for the MIT for a 2017 Sierra 6.2?

tyler.frost92 · October 9, 2017

I just found a GM Performance exhaust tonight while trolling around on the net. I didn't get a chance to research it or know anything about it. Maybe you might want to look into it or maybe someone here knows.

GM part # 23462043.

I'm sort of looking for another exhaust system. My Corsa is loud upon startup and I'm sure about 5 of my closest neighbors don't appreciate it, not to mention I can't touch the accelerator until I get out of my gated community. I really don't want to put the stock exhaust back on it BC it's just as quiet as a Prius. The Corsa is great on the freeway for those times when you get a sleeper in the fast lane holding up the flow of traffic. When they finally move over I roar right past them and wake 'em up!

Do you want to sell the corsa?