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03-19-2021, 01:30 PM | #1 |
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Location: Swaledale, IA
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Need to quiet down exhaust
I finished up my C10 build this winter. Out on the road, its clear the exhaust is a lot more than I was hoping for. The setup I have is a swapped 5.3, with cast camaro manifolds dumping into a 2.5" exhaust, then X-Pipe, dual Dynomax super turbo mufflers after the x-pipe.
I have some strait runs between the manifolds and the beginning of the X-pipe, but limited space around around the pipe. I think I could fit a shorter glasspack muffler in that space (maybe a 20-22" long one). I'd leave the super turbos in of course. Any other ideas I can consider? I need a very compact muffler, there's probably only a few inches around the pipe of room. Traditional muffler will not fit. I want to kill the highway drone noise to a point where I barely hear it. |
03-19-2021, 03:59 PM | #2 |
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Re: Need to quiet down exhaust
You fell into the more is better trap. I'm going with 2.25" exhaust, enough for the small block. AcampoDave,a member here also added resonators at the end of the exhaust before the rear bumper. http://67-72chevytrucks.com/vboard/s...d.php?t=792007
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03-19-2021, 06:04 PM | #3 | |
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Re: Need to quiet down exhaust
Quote:
As Rocknrod Said "the more is better trap" i fell into it with a desire for quietness. Dont hesitate to ask me if you have any questions about the stuff I did. Last edited by AcampoDave; 03-20-2021 at 01:33 AM. |
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03-19-2021, 06:14 PM | #4 |
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Re: Need to quiet down exhaust
I also experimented with hoodliner which you can read about here: http://67-72chevytrucks.com/vboard/s...d.php?t=808418
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03-19-2021, 06:40 PM | #5 |
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Re: Need to quiet down exhaust
And here is where I did the Noico that MikeC recommended. http://67-72chevytrucks.com/vboard/s...d.php?t=814233
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03-20-2021, 07:29 AM | #6 |
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Re: Need to quiet down exhaust
Thanks for the replies! It sounds like a resonator is the way to go. Does it matter if it goes before the mufflers or after? I see some folks putting them right before the exhaust tips.
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03-20-2021, 08:27 AM | #7 |
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Re: Need to quiet down exhaust
Do you have carpet or rubber floor mat kit and full insulation pad ? This will make a big change .
And were is your exits for the pipes ? If they stop under the body even with turn down tips it will be a LOT worse and you need to get them out the back or near the rear sides . And factory tends to put resonators before the muffler mid way from engine and muffler .
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03-20-2021, 10:02 AM | #8 | |
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Re: Need to quiet down exhaust
Quote:
Anyhow, it prompted me to look it up and now they simply don't seem to say. Last edited by AcampoDave; 03-20-2021 at 07:48 PM. Reason: Typo |
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03-20-2021, 06:49 PM | #9 |
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Re: Need to quiet down exhaust
Do you have room for the 20" case DynoMax mufflers? I assume you have the 14" case mufflers? If you do have the 14's, swapping in the 20's only adds 6". Do you have tailpipes? That will go the furthest to eliminate drone and noise over everything else.
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03-20-2021, 10:41 PM | #10 |
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Re: Need to quiet down exhaust
Thanks for all the replies folks. You guys asked for some info on the interior, so heres what I have.
Dynamat on the floorboards, back wall and ceiling. Also a layer on the door skin and on the inside "side" of the door shell (under the panel side). I have new GM door seals (they still make them!), and also added the extra 2nd door seal. I have new carpet with mass backing material. I also have carpet on the back wall. I have the longer (20" case) super turbos installed. THe drone is not awlful, but its there and bothers me. After my original post a few days ago I found I had a few holes that were not plugged in the cab (factory cab had power windows and i removed the wire harness but failed to plug the holes, i have manual windows now). I installed the plugs that the noise inside has dropped some. I can still hear the exhaust drone but not as terrible now. It would get annoying on a longer drive for sure. I'll look at resonators. I have space right after the manifolds (as originally mentioned) but i also could install them right before the exhaust tips it looks like as well. I appreciate all the information provided already! |
03-21-2021, 10:09 AM | #11 |
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Re: Need to quiet down exhaust
Just FYI, my Trailblazer has the resonator before the turn down on the tailpipe. Late model Hemi trucks do too, so a resonator may be effective regardless of where it's located.
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03-21-2021, 02:22 PM | #12 |
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Re: Need to quiet down exhaust
Are your exhaust maifolds old? I was a bit surprised by how warped my old ramhorns actually were. The machine shop guy showed me the pattern on the mating surface after the first run on the machine and it was half planed and still half nasty. He had to let it cool off and go for another round. He said the other one was 2/3rds as bad as the first. When I put them on, (no gaskets) the reduction in noise prompted me turn right around and do my other truck. I just test drove it this morning, and the result is the same as the first. A noticeable reduction of noise at idle and upon normal acceleration. I also noticed it upon deceleration too. At highway speed however, the change was less noticeable due to the wind noise.
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03-21-2021, 03:10 PM | #13 |
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Re: Need to quiet down exhaust
I can tell you my personal experiences with exhaust and resonators. BEFORE the muffler helps quiet down more, AND helps rid the bumblebee sound on 4 & 6cyl, the raspy pops on a V8. Just an overall smoother, quieter tone. On trucks, and especially SUV's, try to get the mufflers as far back as possible. Duals with free flowing mufflers directly under the passenger compartment on an SUV make a TERRIBLE drone at certain RPM's. Resonators AFTER the mufflers still help quiet and smooth out the tone but not NEAR as much. For example a 4 cylinder car with a free flowing muffler will still have that fart can popping when letting off the throttle going downhill, It's just a bit quieter, not as raspy.....VS BEFORE the muffler where those noises go away almost completely.
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03-23-2021, 03:26 PM | #14 | |
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Re: Need to quiet down exhaust
Quote:
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03-23-2021, 04:34 PM | #15 |
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Location: Swaledale, IA
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Re: Need to quiet down exhaust
Heres the link for the seals:
https://www.soffseal.com/ss-9352 I put them on my last truck and it did seem to help with the wind noise a bit. |
03-23-2021, 08:19 PM | #16 | |
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Re: Need to quiet down exhaust
Quote:
Just peel and stick, large flange up? |
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03-24-2021, 01:32 PM | #17 |
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Location: Swaledale, IA
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Re: Need to quiet down exhaust
Yes, they are a peel and stick install. Pretty easy/fast. The "flanges" are up - with the small one against the door shell, and the larger one contacts the cab when the door is shut.
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