Men, woman and children- LEND ME YOUR EARS. I've been chasing drone for awhile now and think I'm attacking the wrong things... hoping to give some background and get the magic answer haha..

2011 silverado 6.2 3.73s, 1 7/8 LT headers with 3'' x pipe dual exhaust from speed-engineering (no cats) and a texas speed VVT3 cam (Cam specs: 216/224, .600"/.600", 112 LSA) ... All tuned from a texas speed mail order tune.

__________________________________________________ __________________________________________________ __________________________________________________ _____________
The truck was both too loud and had far too much drone. so I put in line black widow widowmaker mufflers and cutouts before the speed engineering turbo style mufflers.
The drone got marginally better but any time i use the cutouts its instant mind melting drone so they're not fun to use unless im hammering on it with the windows down.
I then took out the speed engineering mufflers and replaced them with dynamax superturbo mufflers which made the truck again marginally more quiet and slightly less drone. it now became tolerable and I stopped getting complaints by passengers so i thought i was in the clear.

untill! I scored a great deal on 20's with 305/50r20 tires. I swear the drone is worse now. which is making me think its engine load related- I confirmed this by going downhill at these RPM ranges and the drone is almost non-existent.


Can anyone tell me what they would do next?

1. I can put some 3'' resonators after the x pipe but I dont want to even further complicate my exhaust if the problem is cam/engine load related.
2. lizard skin sound proofing
3. lizard skin ceramic coat the mufflers?
4. Would 4.10 gears give me the mechanical advantage I need to offset the additional engine load with the cam?
5. Would a camaro ZL1 torque converter improve this at all(i read it provides a slightly higher stall)
6. Would installing cats improve this?

I really appreciate any help. I'm hoping for my next move to be a little more strategic. Also please note im not opposed to adding cats AT ALL, they simply dont exist because they didnt come with the kit. I havent had an inspection yet so if i pass i dont see a need to put them in. I would rather have them but it comes down to $

-thanks

 

Well of course load is going to be louder. During decel the engine is burning almost no fuel (so no bang), so it should be very quiet. Also unless you have dump pipes for your cutouts point out the sound that is going to be loud in the cab because it points at the ground.

-Dont waste your money on sound proofing
-Cats will quiet it back down
-When a converter is locked they are all the same, an aftermarket converter will not make it quieter
-Steeper gears will move your rpm higher so it may be away from the resonance zone

If you really want it quiet put the stock muffler back on and have a cutout before it.

 

have a custom shop weld in a J-pipe, google it, I did it on my G8, it made a hell of a difference. We can have a conversation in it now and I can hear the kids bitching in the back seat, thats the only down side.

 

Add a resonance tube as mentioned above. There are threads on here about it.

 

I get what you're saying. I anticipated it being loud, im okay with that. its the drone im trying to remove. its genuinely awful

 

Then yea, try the J tube helmholtz resonator idea.

 

Make sure the header isn't against the frame/body anywhere also. Driverside on mine was real close to front diff mount and also under cab. I flattened out a bit of bracing to quiet mine down.
2012 yukon 6.2, 218/228 .600/.600lift, same speed eng long tubes with stock catback zero drone

 

I called the muffler shop to have them take a look and see what they recommend. I hate to give in but they do exhaust work for a reason right?

Im bringing the stock y pipe in hopes they can cut the cats out and put them in. between making it 100% legal and a little more quiet maybe that'll cut the drown down to a healthier stand point. ill keep everyone posted.

I asked him about the capped resonator pipe as well he said hes done that in the past so after the cats in we'll look into that.

-Dana

 

Here's the thread on the resonator
How To Build an Exhaust Resonator Tube to Eliminate Drone