issue Vibration in Floorboard, Not Speed/Tire Related

[DRS 95 Silverado]

I have managed to get rid of about 90% of the exhaust resonance vibration in the floorboard and accelerator pedal.

This is what I have done so far;

Installed the Range V8 which helped some by keeping the engine out of V4 mode.

I Clamped weights to the pipe after the muffler but before the resonator which made a big difference (see pics below). This was done mainly to determine which area of the exhaust was generating the resonance.

I think the bent portion of the pipe going over the rear axle in the spare tire area is causing most of the resonance. The resonator right before the exhaust outlet may have something to do with it as well, but it's definitely being generated after the muffler.

 

Next step will be to install a helmholtz resonator like the one in the pic below. I will make it adjustable until I determine the correct length needed to cancel out the resonance, then it will become permanent.

 

I DID NOT WEIGH the WEIGHTS before mounting.

Thats where my sound seems to be coming from. Mines not too bad but you can hear and feel it come and go a little. I also wonder about the flapper valve. Do you think it has anything to to with it? You ought to take to dealer and let them drive it, then take all the weights of and drive it again. If it's the exhaust in some of these trucks causing problems it should be easy for GM to come up with a solution. I don't think everyone is having the same type of noise/vibration.

[14SLTZ71]

Thats where my sound seems to be coming from. Mines not too bad but you can hear and feel it come and go a little. I also wonder about the flapper valve. Do you think it has anything to to with it? You ought to take to dealer and let them drive it, then take all the weights of and drive it again. If it's the exhaust in some of these trucks causing problems it should be easy for GM to come up with a solution. I don't think everyone is having the same type of noise/vibration.

I drove several of them both 2014 Sierra and Silverado and every one of them had a bit of it however some definitely had it more than others. I am baffled that GM couldn't come up with or didn't care enough to implement a solution during development, surely they knew about it, especially when you look at all the stuff they put on the exhaust to eliminate drone and resonance. 2 resonators, a flex coupling, and a flapper valve for V4 drone.

Edited April 13, 2014 by 14LTZZ71

[14SLTZ71]

I have managed to get rid of about 90% of the exhaust resonance vibration in the floorboard and accelerator pedal.

This is what I have done so far;

Installed the Range V8 which helped some by keeping the engine out of V4 mode.

I Clamped weights to the pipe after the muffler but before the resonator which made a big difference (see pics below). This was done mainly to determine which area of the exhaust was generating the resonance.

I think the bent portion of the pipe going over the rear axle in the spare tire area is causing most of the resonance. The resonator right before the exhaust outlet may have something to do with it as well, but it's definitely being generated after the muffler.

Next step will be to install a helmholtz resonator like the one in the pic below. I will make it adjustable until I determine the correct length needed to cancel out the resonance, then it will become permanent.

I DID NOT WEIGH the WEIGHTS before mounting.

Ok so now I clamped the flapper valve open and it helped a little more, almost completely gone, but I may have lost a slight bit of low end torque?.. So I will probably take it off. Edited April 13, 2014 by 14LTZZ71

[14SLTZ71]

I cut the rear resonator off and tried the 32 dump mod. I removed my V8 Range Device and drove the truck. Removing the resonator helped with the vibration/buzzing sensation in the floor and gas pedal, especially after the engine warms up. Its still there but the frequency rate has slowed down so its not as aggravating.

I do hear a slight exhale and inhale if I'm standing next to the tailpipe area when I start it up or shut it down. I think the adaptive valve causes this and the resonator was put there so you wouldn't hear it.

The adaptive valve (aka; flapper valve) is not clamped open.

 

If I clamp the valve open I get a random V4 Drone and a helicopter sound.

Edited April 29, 2014 by 14LTZZ71

[BR-TEXAS]

I cut the rear resonator off and tried the 32 dump mod. I removed my V8 Range Device and drove the truck. Removing the resonator helped with the vibration/buzzing sensation in the floor and gas pedal, especially after the engine warms up. Its still there but the frequency rate has slowed down so its not as aggravating.

I do hear a slight exhale and inhale if I'm standing next to the tailpipe area when I start it up or shut it down. I think the adaptive valve causes this and the resonator was put there so you wouldn't hear it.

The adaptive valve (aka; flapper valve) is not clamped open.

 

If I clamp the valve open I get a random V4 Drone and a helicopter sound.

Any updates?

[14SLTZ71]

I installed the Borla CatBack Exhaust # 140544 and it had drone in V4 mode, sounded like a flutter or helicopter. So I sent it back to Borla and now I am back to the 32 dump mod. I should have installed the Borla GM version because it comes with the valve in the front pipe but it also cost $300 more.

I still have some vibration/buzzing sensation in the floorboard and accelerated pedal but now I am just trying to ignore it, which is difficult to do.

 

I'm not using my range V8 device because I need to send it back to the manufacture so they can update it, but. I have version 4 and the current version is 6+.

Edited June 16, 2014 by 14LTZZ71

[20Denali22]

I installed the Borla CatBack Exhaust # 140544 and it had drone in V4 mode, sounded like a flutter or helicopter. So I sent it back to Borla and now I am back to the 32 dump mod. I should have installed the Borla GM version because it comes with the valve in the front pipe but it also cost $300 more.

I still have some vibration/buzzing sensation in the floorboard and accelerated pedal but now I am just trying to ignore it, which is difficult to do.

 

I'm not using my range V8 device because I need to send it back to the manufacture so they can update it, but. I have version 4 and the current version is 6+.

Just run it in M5 around town and you won't have the drone until your Range device comes back.

[TxTruckMan]

I've had no luck getting resolution to my floorboard vibration either.

[14SLTZ71]

Just run it in M5 around town and you won't have the drone until your Range device comes back.

Yea, I am aware of M5.

 

I've had no luck getting resolution to my floorboard vibration either.

I am pretty sure the buzzing/vibration sensation in my floorboard is from the exhaust that sits directly under my feet. GM didn't even install an exhaust shield on the underside of the drivers floorboard on these trucks. If I lift up my carpet the floor is hot under my feet, so I am pretty sure the resonance in the exhaust is vibrating the floorboard.

Edited June 16, 2014 by 14LTZZ71

[TxTruckMan]

That's what it feels like.

[14SLTZ71]

That's what it feels like.

 

 

Do you feel it more when the truck is in 6th gear and even worse in 6th gear & V4 mode.

 

Lately I just drive around in M5 w/traction control off, sometimes I reach 70mph and the rpms are still only 2000 - 2100, but I try to stay below 65, otherwise I will put it in M6. The truck feels so much better versus driving around in D.

Edited June 19, 2014 by 14LTZZ71

[TxTruckMan]

I feel it in every gear as it passes 1700 rpms. V8 or V4 - usually V8.

[Spurshot]

I recall my brother having a flex plate balancing weight come off and he had a vibration that took a while to locate the cause of.

[Newm]

Well add me to the list. I have what I would describe as a humming or vibration in my gas pedal. Not speed related but rpm and engine load related to me. It's just started and feel it between 1500 and 1850 rpms with V4 or V8 mode making no difference. More pronounced under slight load. My first thought, like some on here, is that it's exhaust related somehow. Anyone find a resolution?

[14SLTZ71]

Well add me to the list. I have what I would describe as a humming or vibration in my gas pedal. Not speed related but rpm and engine load related to me. It's just started and feel it between 1500 and 1850 rpms with V4 or V8 mode making no difference. More pronounced under slight load. My first thought, like some on here, is that it's exhaust related somehow. Anyone find a resolution?

Dealership tells me it's the torque converter and operating within the normal characteristic of the design of the vehicle. I believe it's exhaust resonance causing the floorboard to vibrate between 1600 and 1800 rpm because the floorboard seems to be very vulnerable to vibration. I can even feel it vibrate when I make adjustments to the adjustable pedals. Probably due to the floor pan not being thick enough. I tried numerous things with very little success. A secondary or thicker floor pan would probably do the trick? For some unknown reason GM didn't even install exhaust shields on the driver's and front passenger floorboards.

Edited July 9, 2014 by 14LTZZ71