07 NBS Crew Cab LT1 interior noise help

Tlowe · July 24, 2015

Last year I found a deal on a 07 NBS LT1 Crew Cab with 53000 miles and just couldn't pass it up. Truck was very plain, pretty much no factory upgrades except for the towing package and it has the Vinyl flooring rather than carpet. Previous owner added flowmaster, nurf bars and after market trailer brakes.

I have added the DIC upgrade,chrome grill, bug guard, front reese hitch, rugged bed liner and leveling kit.

Although I love a hotrod truck, the exhaust noise in the cabin is just too much. The drone and changing of the sound when AFM in kicks will put you to sleep on a long drive because you can barely hear the radio at a normal level and conversation with someone in the backseat is annoying.

I know there are a lot of flowmaster haters out there but I didn't chose the muffler.

So, I want to put my money where it will make the most impact and not negatively affect the performance of my truck. Do you all believe the issue is strictly the muffler choice or is this a side effect of the vinyl flooring and I need to pull out the back seat to work on sound deadening?

Has anyone had the same issue and how did you resolve it.

Thank you for your input

newdude · July 24, 2015

Is it just a muffler that's on there or a whole cat back system? If it is just the muffler, I bet it is a short bodied one, probably a 14 inch body which would be the cause of the loud interior. I can say from experience that if you change out for a full cat back system that will have stock or slightly louder noise levels on the inside, Corsa is where my money will go every time. I just installed mine on my 2015 HD and on the inside you know it's not stock when you open it up but there is ZERO unwanted drone or loud interior noises. The Magnaflow cat back I had on my 2012 made more inside noise than outside.

Tlowe · July 24, 2015

15HDriver, I honestly dont know if it was just a muffler change or a whole cat back. I will get some time later today to take a closer look. I do know that if you look between the cab and the bed, you're looking straight down at the center of the muffler.

maplesig · July 24, 2015

I have a dynomax catback and for the money I couldn't be happier. No drone and has a great sound when you step on it.

desrtrat · July 24, 2015

i would change out the Flowmaster with a better quality muffler, and place it back in the stock location, and dump it over the rear.

Tlowe · July 24, 2015

I can certainly switch out the flowmaster to another brand. However, does anyone see this as a problem with the vinyl floor? I am just asking because I would suspect the carpet and padding have some better sound deadening than the Vinyl.

I like the vinyl and would like to keep it but just dont want to change out the exhaust and have the same problem since the exhaust is still in like new condition.

Tlowe · July 25, 2015

Destrat,

Thanks for the input. I checked the numbers on the muffler last night and it is a 40 series Flowmaster and it has definitely been moved forward from stock location. With this in mind and reading Flowmasters description of the muffler, I will definitely start with addressing the exhaust rather than the interior.