New Exhaust, now loud vibration/droning noise in cab

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Serge627

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Hey guys,

A week or so ago I had a set of long tube headers put on the truck and the remainder of the pipe replaced, with exception of the mufflers (they were still good). Truck runs fine and it sounded great. I have maybe put only 30 miles on it since the work was done. The problem I noticed yesterday is that it has a loud droning/buzzing/vibrating/noisey sound inside the cab. Loud enough so it feels like its putting pressure on your head and its nasty sitting in it. It reminds me of being in a cab where the truck has a large hole before the muffler.

I felt around the weld spots on the pipes and the collectors and I only felt a small amount of air coming from two or three of the welds. I am going to take it back and have the welds re done, but would that small amount of air cause this issue? or might it be something else?

Thanks guys.
 

Jims86

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Hey guys,

A week or so ago I had a set of long tube headers put on the truck and the remainder of the pipe replaced, with exception of the mufflers (they were still good). Truck runs fine and it sounded great. I have maybe put only 30 miles on it since the work was done. The problem I noticed yesterday is that it has a loud droning/buzzing/vibrating/noisey sound inside the cab. Loud enough so it feels like its putting pressure on your head and its nasty sitting in it. It reminds me of being in a cab where the truck has a large hole before the muffler.

I felt around the weld spots on the pipes and the collectors and I only felt a small amount of air coming from two or three of the welds. I am going to take it back and have the welds re done, but would that small amount of air cause this issue? or might it be something else?

Thanks guys.

You have flowmasters?
do you have dumps after the mufflers, or do they go all the way to the back of the truck.
How did they hang it?
 

Serge627

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They are thrush welded mufflers, they do a 45 deg or so turn down, just prior to the rear axle, and they used regular rubber style to metal clamp hangers.
 

89Suburban

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I don't miss those days. Stock FTW.
 

Jims86

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They are thrush welded mufflers, they do a 45 deg or so turn down, just prior to the rear axle, and they used regular rubber style to metal clamp hangers.

Ok, 2 things...Those mufflers are flowmaster knock offs, and even flowmatser 3 chambers are kind of obnoxiuse with turn downs.
Turn downs are bad. The noise bounces off the pavement, and reverberates under the bed and cab. Full tailpipies would fix your issues, and you may like the sound even better, and you may get a little bump in Torque and MPG.
Dont go any larger than 2 1/4 duals.
 

Serge627

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Ok i never thought of the reverb from the turndowns, as they arent really pointed straight down and are more of a 45 deg angle, but that is a good thought. I dont know how willing they will be to redo the exit point, so if i angle the exits to the side of the truck from the turndowns, instead of toward the ground would that be better? It seems like that would keep it from pounding towards the ground and more to the side instead.
 

Jims86

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Ok i never thought of the reverb from the turndowns, as they arent really pointed straight down and are more of a 45 deg angle, but that is a good thought. I dont know how willing they will be to redo the exit point, so if i angle the exits to the side of the truck from the turndowns, instead of toward the ground would that be better? It seems like that would keep it from pounding towards the ground and more to the side instead.

The sound waves expand immidiatlely after exiting, so you can turn them out and extend them to exit in front of the tires, then pointed back a little, but over the axle and back is best, but you do not want ANY exits under the truck, regardless of where they are pointed.
 

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The sound waves expand immidiatlely after exiting, so you can turn them out and extend them to exit in front of the tires, then pointed back a little, but over the axle and back is best, but you do not want ANY exits under the truck, regardless of where they are pointed.

Thats no fun. Open headers are :D
 

Serge627

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Ok, thanks for the replies. I will see what they are willing to do for me. Even if I have to throw a few bucks at them that may be the best option for me I guess.
 

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So it's been this way since the work was done?

Exhaust all the way out the back is the only way to go. Even ending under the bed adds a ton of interior resonance.
 

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