Hey everyone, I had 2.5” dual Magnaflow 11” body mufflers installed on my 2005 Ford F-150. It sounded great, but the sides were unequal. I took it back to the shop and had an X-pipe installed. It equaled out the sides, but took away the volume/aggression from the exhaust as well as caused a pretty significant drone. Any other solutions to maintain that true dual sound without the drone?

 

To eliminate noise, you add resonators and mufflers. Nice and quiet in the cab. Then it's also not as loud on the the street. A lot of people will tell you to use different size pipes, exhaust tips, and suggest brand names like Borla, MagnaFlow, FlowMaster........ Are you looking to make noise to turn heads? Or just to satisfy yourself that it sounds a certain way? Exhaust tuning for sound effect? Or exhaust tuning for performance? Very expensive to reconfigure an OEM exhaust system. Very little gain to be had. Unless you find the perfect combination of pipes and mufflers to feel good about when you hear it.

 

Do some reading on Branch resonators/ j pipes. That is one of the only ways you can eliminate droning frequencies without lowering the volume of your exhaust outside.

I'll be fabricating one for my truck later this year. You'd need two since you have true duals.

You find the frequency of the drone using an sound spectrum app, and use the calculations people have put together to calculate how long the j pipe (branch resonator) needs to be to counter the droning frequency. It only works on ONE frequency and usually mutes a range of hertz close by. Usually you don't want drone on the highway, so you use the app at your cruising rpm to find the excessive frequency in hertz.

Sounds nutty, but it works. Also called a 1/4 wave resonator. I've done an insane amount of reading and watching on these.

 

I wouldn’t mind for the truck to sound good and turn a few heads, but I’ve done it mostly for my own gratification. Before the x pipe it sounded great outside and inside the cab with zero drone. After the x pipe, the sound inside the cab has been replaced with a drone. There’s no drone when on the interstate, just at heavy acceleration obviously caused by the x pipe. Just curious is this could be fixed with a different style x pipe, having the x pipe placed in a different spot, etc.

 

If you want to redo the system, get a single DI/DO muffler with an internal X-pipe.

 

I don’t “want” to redo it, but I’ve looked into that option. Just hoping there’s an easier alternative.

 

Not to sound like a jerk, but I have you your solution above. The only scientific way to remove the drone without affecting the tone is a branch resonator.

It's not made up, do some reading and you'll see or watch videos on youtube.
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Yesterday I checked the frequencies on my own truck for the drone. It's not bad since I have switched to Borla Pro XS for the meantime, but my dominant frequencies at 70mph are 73hz and 120hz. You build the j pipe (branch resonator) based on those frequencies. 120hz is the most intrusive from listening to those frequencies on YouTube test clips, so that's what I would build mine around for my particular system and drone.

It's the only solution. Anyone who says otherwise is incorrect. Not to sound harsh, but adding resonators l, changing mufflers is no guarantee. You end up chasing no drone and could wind up with it too quiet or sounding different because you have changed mufflers. This method gets the results because it's targets the frequency that resonates in your interior and leaves the great sound outside where it belongs.