3" Quiet Exhaust

Discussion on fuel delivery & intake/exhaust tech & mods.
Seabass
Posts: 23
Joined: Mon Jan 13, 2020 11:56 am

Re: 3" Quiet Exhaust

Post by Seabass »

Have any of you considered merging into a single tube under the car instead of a X or H? this should average out the exhaust pulses and make more of a purr over a lope or chop.
14 Caprice
Looking for a white or silver 11-12
Looking for:
complete stock exhaust
Ls3 intake
bstoner
Posts: 233
Joined: Wed May 05, 2021 2:12 pm

Re: 3" Quiet Exhaust

Post by bstoner »

Right now I have ARH headers on order with cats and coated and they are probably 4-8 weeks out. I plan on putting in a Magnaflow dual pipe resonator in place of the X pipe then run dual Magnaflow resonators out to Solo quiet mufflers. The Magnaflow dual pipe resonator 12469 is pretty much what you describe. The dual pipes neck down to a single pipe and open back up into duals. It may be a small restriction but the noise reduction is a priority for me.
2014 Caprice PPV, 6.0L, BTR Stage 2 Cam, 3.45, 3" exhaust, Rotofab intake, Chris Henry tuned, future LSA....
bstoner
Posts: 233
Joined: Wed May 05, 2021 2:12 pm

Re: 3" Quiet Exhaust

Post by bstoner »

My ARH headers. cats, and pipes came in. Unbeknownst to me a 3" kit actually means 3" to the straight mid-pipes then it necks down to 2.5" where the two pipes angle outward to clear the rear diff. I am undecided if I should run the 2.5" pipes (along with 2.5" mufflers) or replace it with 3". I may also contact ARH to see if they can swap the 2.5" pipes for 3" pipes but I doubt it.
2014 Caprice PPV, 6.0L, BTR Stage 2 Cam, 3.45, 3" exhaust, Rotofab intake, Chris Henry tuned, future LSA....
s/c'd cav
Posts: 1382
Joined: Mon May 30, 2016 3:12 am
Location: PHOENIX AZ

Re: 3" Quiet Exhaust

Post by s/c'd cav »

unless you are making over 1000whp , or drag racing it on a daily basis , you are completely fine
bstoner
Posts: 233
Joined: Wed May 05, 2021 2:12 pm

Re: 3" Quiet Exhaust

Post by bstoner »

My target is 800 hp. LS3 block (or more depending on funds), LSA maybe 2300, E85 and obviously all supporting mods to get there. Probably about 5 years out based on budget. I have read mixed things over on SSForums and Camaro5. Some say go 3 inch if you are going F/I. Others say 2.5 becomes limiting around 500-600 hp. Yet others say 2.5" is fine. If I stayed with the ARH I would have 2" headers, 3" collectors, 3" cats/midpipes/resonators, and 2.5 mufflers and tips.
2014 Caprice PPV, 6.0L, BTR Stage 2 Cam, 3.45, 3" exhaust, Rotofab intake, Chris Henry tuned, future LSA....
s/c'd cav
Posts: 1382
Joined: Mon May 30, 2016 3:12 am
Location: PHOENIX AZ

Re: 3" Quiet Exhaust

Post by s/c'd cav »

ive got a few friends running 3" into 2 1/2" and making over well 800whp , 1 is a G8 GXP manual runs mid-low 10's using the kooks knock off 1 7/8 headers , another is a SS and was running mid 9's using the arh with 2" headers

my caprice will be going together with the SS arh 2" system
BluesBro
Posts: 134
Joined: Tue Aug 03, 2021 1:26 am

Re: 3" Quiet Exhaust

Post by BluesBro »

I'd try to get 3" all the way out if you are planning on F/I, exhaust velocity is a huge factor. Going from 2.5" to 3" would be less of a problem than necking down 3" to 2.5". I don't like doing things twice, and have a similar timeline if not longer for a F/I setup on mine, as such straight to a 3" exhaust. It is overkill right now but at least I wont be redoing the cat back.

I don't doubt 2.5 setups can handle the flow, more of a mental thing for me I guess.
2014 Caprice PPV 6.0L - TSP Stage 1 Cam, Solo 3in Mach Cat Back, VCM OTR, Pedders Coilovers, HP Tuned
2002 Avalanche 5.3L - MBRP Exhaust, RC 6in Lift
s/c'd cav
Posts: 1382
Joined: Mon May 30, 2016 3:12 am
Location: PHOENIX AZ

Re: 3" Quiet Exhaust

Post by s/c'd cav »

BluesBro wrote: Fri Sep 17, 2021 12:32 pm I'd try to get 3" all the way out if you are planning on F/I, exhaust velocity is a huge factor. Going from 2.5" to 3" would be less of a problem than necking down 3" to 2.5". I don't like doing things twice, and have a similar timeline if not longer for a F/I setup on mine, as such straight to a 3" exhaust. It is overkill right now but at least I wont be redoing the cat back.

I don't doubt 2.5 setups can handle the flow, more of a mental thing for me I guess.
LMFAO !!!!!!!!

the farther away from the exhaust port the velocity of the exhaust SLOWS down , so dropping from 3" into 2 1/2" will keep the velocity up , it also doesnt help with our cars being so long

as i mentioned , if he is doing a full tilt drag car then , yes all 3" is the way to go , for a street car that sees random track time , then the drop to 2 1/2" is fine
bstoner
Posts: 233
Joined: Wed May 05, 2021 2:12 pm

Re: 3" Quiet Exhaust

Post by bstoner »

It's in!!!!

Setup:
I have 2" primaries ARH Headers coated, their 3" high flow cats, and X-pipe for a Chevy SS. (Note their kit is 3" to the midpipes then necks down to 2.5" where it bends out to clear the diff and turns outward.) Then I am using a Magnaflow 12469 dual in/out muffler. This is the largest muffler/resonator that will fit in tunnel. Next is dual Magnaflow 14419 resonators. I used a set of mandrel bends to clear the diff and turn out to the mufflers. I reused a connection from the ARH kit so I can remove the mufflers. From there another 90 bend to Solo Performance QTM12 mufflers. And then finally a set of eBay Trapezoid Tips. I installed the headers, x-pipe, and first resonator. Shop installed the rest and welded it all up for me. Charged $400.

Review:
It is as quiet as stock. Zero drone so far. Sounds pretty much like stock but the tone is deeper while accelerating. I also notice more engine noise. Of course all this makes sense. Larger diameter pipe makes the sound deeper. Thinner header pipe thickness allows more engine noise through and less dampened. I have DOD turned off so I can't comment on that difference. I am running two resonators and a muffler. I absolutely love it. I am going for sleeper and it hits my target perfect. Now if you want more noise or exhaust note I would probably recommend switching to different mufflers or maybe deleting one of the resonators. The Magnaflow 12469 is an internal crossover, it goes 2 into 1 back into 2, straight through. The Magnaflow 14419 are straight through with packing around the outside. The QTM12 are single in, split into 2 inside, back into 1, straight through as well.

So all in all if you want 3" performance exhaust that is factory quiet this is the way to go. This weekend I will try to get a video or two.

Forgot to mention. In HPTuners I also turned off P0420, P0430, P2097, and P2099 for the high flow cats.
2014 Caprice PPV, 6.0L, BTR Stage 2 Cam, 3.45, 3" exhaust, Rotofab intake, Chris Henry tuned, future LSA....
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kevink
Posts: 480
Joined: Sun Aug 09, 2015 12:55 pm

Re: 3" Quiet Exhaust

Post by kevink »

bstoner wrote: Thu Oct 28, 2021 9:25 am It's in!!!!

Setup:
I have 2" primaries ARH Headers coated, their 3" high flow cats, and X-pipe for a Chevy SS. (Note their kit is 3" to the midpipes then necks down to 2.5" where it bends out to clear the diff and turns outward.) Then I am using a Magnaflow 12469 dual in/out muffler. This is the largest muffler/resonator that will fit in tunnel. Next is dual Magnaflow 14419 resonators. I used a set of mandrel bends to clear the diff and turn out to the mufflers. I reused a connection from the ARH kit so I can remove the mufflers. From there another 90 bend to Solo Performance QTM12 mufflers. And then finally a set of eBay Trapezoid Tips. I installed the headers, x-pipe, and first resonator. Shop installed the rest and welded it all up for me. Charged $400.

Review:
It is as quiet as stock. Zero drone so far. Sounds pretty much like stock but the tone is deeper while accelerating. I also notice more engine noise. Of course all this makes sense. Larger diameter pipe makes the sound deeper. Thinner header pipe thickness allows more engine noise through and less dampened. I have DOD turned off so I can't comment on that difference. I am running two resonators and a muffler. I absolutely love it. I am going for sleeper and it hits my target perfect. Now if you want more noise or exhaust note I would probably recommend switching to different mufflers or maybe deleting one of the resonators. The Magnaflow 12469 is an internal crossover, it goes 2 into 1 back into 2, straight through. The Magnaflow 14419 are straight through with packing around the outside. The QTM12 are single in, split into 2 inside, back into 1, straight through as well.

So all in all if you want 3" performance exhaust that is factory quiet this is the way to go. This weekend I will try to get a video or two.

Forgot to mention. In HPTuners I also turned off P0420, P0430, P2097, and P2099 for the high flow cats.
I'm surprised that this is as quiet as stock. When you say that it's as quiet as stock, do you mean you can't hear it running at all at idle? Because that's how quiet stock is. At least my '11 was silent in factory form...
2011 9C3: 11.48 @118.
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