Engine/Transmission (1998.5 - 2002) Drone ore something else?

[tharonian]

Newbie here.

Trying to figure out a low frequency sound that kicks in around 2100 rpm on the highway. Its not steady but reverberates louder then softer... kind of like rrrRRRrrrrrRRRRrrrrrRRRRR. The start of this seems to have coincided with adding MBRP 4 inch turbo-back exhaust. I also seem to hear the valve-clatter fluctuate slightly in synch with this noise. All worse when accelerating or pulling. Ideas??

Thanks.



01. 5 2500 4x4, quad, edge EZ, ISS pro, wastegate stuck shut, MBRP 4"

 

[johncameron]

My 4 inch exhaust has the 2100rpm drone too. That seems to be normal with most straight through exhaust systems. The Valve clatter thing could be injection timing fluctuation which is not good. A failing VP-44 can do that and mine did.



John

 

[HookMeUp]

Newbie here.

Trying to figure out a low frequency sound that kicks in around 2100 rpm on the highway. Its not steady but reverberates louder then softer... kind of like rrrRRRrrrrrRRRRrrrrrRRRRR. The start of this seems to have coincided with adding MBRP 4 inch turbo-back exhaust. I also seem to hear the valve-clatter fluctuate slightly in synch with this noise. All worse when accelerating or pulling. Ideas??

Thanks.

Do you have a BHAF or AFE air filter? Mine does it all the time depending on load. If you put your ear down by your air filter you can probably hear it while idling.

 

[NoSeeUm]

I get the drone at about 2000 RPM with a 4" exhaust and muffler. From what I have read this is pretty normal. I'm going to try 2 mufflers to try to anti-resonate it.

 

[dmhollister]

I also had the drone after before and after installing an exhaust.



I took the back seat out and installed some sound reducing material I got from JC and it helped out a bunch. The wife doesn't mind the sound any more. It was a quick install and only cost about $50.