I just installed a 50-Series Delt-Flow on my 4.6L Supercab. I have two issues I'd like to fix that seem conflicting. YOUR HELP IS NEEDED FAST!

First, it's not as much rumble as I was looking for, especially at idle.

Second, I'm getting a drone at 1800-1900 rpm which is right at 65 mph where I drive frequently.

I read many of the entries here about muffler placement and went out and looked under my truck. It looks like the muffler is already installed as far back as it can go (just before the pipe bends up and over.

The guy at RPMoutlet.com suggested that I install a dynomax "bullet" resonator before the muffler to "kill" the drone -- he said he's fixed it that way before.

My worry is that to fix the drone I'm going to get further away from my goal of a nice deep rumble out of the exhaust.

SUGGESTIONS??

 

I am just curious. I hack sawed my old muffeler out and installed a glass pack in its place. I do get a nice rumble at idle and up to full throtle. What exactly is this drone you are talking about? Is it only when you are at those rpm's and driving at a steady pace? My pipe still exits out the side of the truck after the rear tire like it did as stock. Do you still have the exit out the side of the truck? Is it in the front or rear of the tire?

 

Basically I just replaced the muffler and put a 3" chrome tip on the end. The rest of the exhaust is stock and still exits the side behind the rear tire.

The drone is at 1800-1900 rpm when the engine is under load. I can hear it as I pass through that zone during accelleration and during steady/hwy cruising.

 

I get that drone at 1600-1700, right at around 62 w/ 3.73 diff. The dealer replaced the exhaust (it's still stock), and it seemed to lessen the noise, but I think it's still noticeable. If it is exhaust resonance, then some kind of dampener should do the trick. Otherwise, changing the resonant frequency will just shift the noise to some other rpm range.

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Model: '99 F150 Lariat Supercab 4x4 SS Mechs: 5.4L, 3.73 Diff (9.75" LSD Rear, 8.8" Front)
ORP: Skid Plates, LT265/70R17 GY Wrang. AT/S
Group III towing: HD Electrical/Cooling, GVWR 6500# (Extra leaf spring).
Stuff: Step Bars, 4W Disc ABS, K&N filter, 0W-30 Series 2k Amsoil @ 8200 miles
Stock Items That Differ Across F150s: Steel Driveshaft, Oil filter bolted to engine w/ drip guard, 4R70W transmission.

 

I think that's why the guy I bought the muffler from suggested the Dynomax Bullet resonator to help me. He's put it on other vehicles with the problem and he "gaurantees" it will take car of the problem.

I think what I might do is go the resonator route, but go to the Delta-40 instead of the Delta-50. Get the sound, but ditch the drone. I hope that works. Any thoughts?

 

But if you already had the drone wouldn't the 40 series make it louder since its more aggressive than the 50 series?

 

I get what you're saying. That's the whole issue for me. I wan't more rumble and don't mind the right kind of noise in the cab. I'm just trying to get rid of the higher-frequency drone which the resonator is supposed to do. If I get more low-frequency rumble that's ok with me -- in fact that's what I was orginally looking for.

I was hoping someone had this same problem and could advise. None of the notes from the guys who run 40-deltas mention drone and seem to like their sound.

I want more of the right sound (rumble) and less of the wrong sound (drone).