Muffler Delete question

CMSearle2 · January 11, 2017

man i'm still on the fence about exhaust.. so much reading.. so many choices.. so many configurations....!!!...i get nervous about the helicopter sound....... i mean i'd like to just cut it before the last cat, run 3 inch all the way back and dump before the axle ... .. but i'm stuck on the muffler... borla. .corsa, flowmaster, grrr... ..makes my head spin

This exactly. Same boat haha.

lawn boy · January 13, 2017

Since the flapper is before the final resonator, is it possible to do a straight pipe from the flapper back and still get some added sound without the "chopper" effect?

GMC_SD_Ult_16 · January 13, 2017

Since the flapper is before the final resonator, is it possible to do a straight pipe from the flapper back and still get some added sound without the "chopper" effect?

Lawn boy,

I am not sure of the sound gain you will get with removing the resonator only but what most of us seem to be fighting is that the flapper seems to add a flutter/chatter in the exhaust since it has less sound deadening going on around it...I have opened the flapper and it sounds much cleaner but just a little on the louder side with a small amount of drone. See if YouTube has any examples of a resonator delete and that may help you hear compared to a muffler delete. My 2 cents. Good luck to all trying to find that sound.

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bdbake01 · January 13, 2017

Resonator delete really just changes the tone, not the volume. And in my opinion, changes it for the worse. More raspy, less throaty (if those terms are even descriptive).

I would encourage those with flapper rattle to investigate the mechanics of the flapper itself. The rattle is often things such as a loose/broken spring, bad weld in the flap, misaligned shaft, loose shaft, etc. Literally the metal parts of the mechanism are slapping around against one another for some reason. And it's usually and easy fix.

GMC_SD_Ult_16 · January 13, 2017

Resonator delete really just changes the tone, not the volume. And in my opinion, changes it for the worse. More raspy, less throaty (if those terms are even descriptive).

I would encourage those with flapper rattle to investigate the mechanics of the flapper itself. The rattle is often things such as a loose/broken spring, bad weld in the flap, misaligned shaft, loose shaft, etc. Literally the metal parts of the mechanism are slapping around against one another for some reason. And it's usually and easy fix.

Thanks bdbake01.... I did not realize the flapper could be adjusted potentially.

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bdbake01 · January 13, 2017

Thanks bdbake01.... I did not realize the flapper could be adjusted potentially.

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Well, "Adjust" may be a stretch Take a look at closely. There aren't any screws, etc to tweak it. But if the spring has jumped out of the track or broken, it'll rattle like mad. The shaft really doesn't have any bearings installed where it passes through the pipe, so if the clearance is excessive, well the flap & shaft will rattle against the pipe. If it's minor, then a cold punch and a hammer can close up the clearance and stop the rattle. Otherwise, may have to replace. The flap itself should be FIRMLY attached to the shaft. If the welds are broke or shoddy, could be flopping around. Etc etc. GM has replaced a ton of these for rattles on stock vehicles, which is probably their best approach. Just comes down to questionable and inconsistent quality from their supplier.

bdbake01 · January 13, 2017

This look like a high tolerance piece? But notice one has some hi temp rubber under the spring? Some have tried this to eliminate the loose spring rattle. Takes up the space and adds dampening.

GMC_SD_Ult_16 · January 14, 2017

This look like a high tolerance piece? But notice one has some hi temp rubber under the spring? Some have tried this to eliminate the loose spring rattle. Takes up the space and adds dampening.

OK. I see the rubber you are talking about on the inside of the bottom picture. It could also be the spring as you noted.. I will look to crawl under it tomorrow and see what can be adjusted.. Unfortunately for me I don't have an ability to cut it off without the help of a muffler shop.

What part are you saying to look and punch with a hammer?

Are you saying the major spring that is part of the rotating system on the outside can be out of place or broken?

And maybe to be clear for me what are the best items that I can look at from the outside.

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GMC_SD_Ult_16 · January 21, 2017

So today I decided to take a chance... I removed the resonator and flapper. I had already deleted the muffler and now I have added a Magnaflow 12909 - 22". I have very little drone or v4 helicopter on highway or just cruising, a nice deep tone but light sound around the neighborhood. Good strong tone when rpms get above 1700 or so. Only had in for a few hours but so far so much better for my needs. Doesn't sound like a Prius or a truck that can wake the neighbors just light driving through the area. Good luck in finding your sound.

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Luster · February 1, 2017

Had a !muff mod since '14. BUT, I didn't just half a$$ it.

Removed muffler (obviously), moved resonator to the original muffler position. Moved flapper, unmodified, to a spot immediately after the now relocated resonator (literally 1/2" away). Added an eBay special stainless (HAHA!) Y-pipe and ran duals over the axle and out the back.

Love it. LOVE IT. It is THE perfect balance IMHO between volume and sound quality. Everyone is amazed. Exhaust dude, seasoned pro, amazed. Recommends to ALL of his clients.

No drone. NONE. NO. ZERO. Let me repeat that because I know what's coming next, I HAVE NO DRONE WHATSOEVER. PERIOD. NONE. Get my drift?

Tried strapping the flapper open, immediate drone. GM knew what they were doing. It changes the effective volume of the exhaust. Works.

Wouldn't change a G-Damn thing. Also, I'll keep that ~$800 in my pocket thank you very much.

Did you do a y-pipe AFTER the relocated resonator into duals out the back.?

bdbake01 · February 2, 2017

Did you do a y-pipe AFTER the relocated resonator into duals out the back.?

Yep. Final setup was original 3rd cat in stock location -> relocated resonator in location of removed & discarded stock muffler -> relocated flapper -> Y pipe/splitter -> dual pipes over the axle and straight out the back.

FYI, the resonator/flapper/Y-pipe are pretty much welded directly to one another. All 3 pieces more or less fit into the space previously occupied by the oem muffler.

Luster · February 2, 2017

Yep. Final setup was original 3rd cat in stock location -> relocated resonator in location of removed & discarded stock muffler -> relocated flapper -> Y pipe/splitter -> dual pipes over the axle and straight out the back.

FYI, the resonator/flapper/Y-pipe are pretty much welded directly to one another. All 3 pieces more or less fit into the space previously occupied by the oem muffler.

That's awesome! Never seen that done but I'm considering it. I have a Flowmaster 10 in the stock muffler location, flapper delete, rez delete and rear exit in the stock location.

I'm thinking I want duals out the rear but don't really don't want to buy another muffler (the FM 10 is the 5th one that's been on the truck; each one progressively louder)

I love the sound, but I want dual rear exit.

I don't suppose you have any pics of your undercarriage???

bdbake01 · February 2, 2017

That's awesome! Never seen that done but I'm considering it. I have a Flowmaster 10 in the stock muffler location, flapper delete, rez delete and rear exit in the stock location.

I'm thinking I want duals out the rear but don't really don't want to buy another muffler (the FM 10 is the 5th one that's been on the truck; each one progressively louder)

I love the sound, but I want dual rear exit.

I don't suppose you have any pics of your undercarriage???

Short answer, yes. But I can't find my post (made a write up) and search doesn't go back that far. I think it was early 2015 maybe?

Luster · February 2, 2017

Short answer, yes. But I can't find my post (made a write up) and search doesn't go back that far. I think it was early 2015 maybe?

My exhaust guy will know what to do.

OldBlue61 · February 9, 2017

man i'm still on the fence about exhaust.. so much reading.. so many choices.. so many configurations....!!!...i get nervous about the helicopter sound....... i mean i'd like to just cut it before the last cat, run 3 inch all the way back and dump before the axle ... .. but i'm stuck on the muffler... borla. .corsa, flowmaster, grrr... ..makes my head spin

I couldn't agree w/ this post more. I've read just about every exhaust thread here, and I'm still on the fence. I have a 5.3, and I think that as soon as the weather breaks I will do the same mod that bdbake01, kkmitchell5 and others have done; delete the muffler, move the resonator to the muffler location, mount the flapper directly behind the newly relocated resonator, and run the tailpipe out to the original location. Worse comes to worse and I don't like it, I'll replace the resonator w/ the 18" MagnaFlow and try that out.

Many thanks to all that have contributed to this thread!