I want to run new exhaust on my 2001 f150 5.4! I want true duals that Y off under the cab with 4 2.25" tailpipes going over the axle going into 4 4" tips out the corners. Now the big concern whats it going to sound like any ideas? Tell me what you think and be honest!!!
Thanks boys

 

I did true dual 2.5" exhaust on a Dodge pickup (400ci engine) with Quad 2.5" tails out in front of the rear tires. The Mufflers were Cherry Bomb Vortex V-Baffle aka. Ravin Z-55 and the sound was deeper with the dual out mufflers but the drone in the cab was far worse vs. the same mufflers with single outlets. I actually went back to glasspacks for the peace and quiet in the cab.

I would never attempt this again, after 40 miles of listening to the cab vibrate I wanted to burn the truck. Even though this wasn't on a Ford, I'd expect the same results. Putting the tail pipes at the rear of the truck may help though.

 

I would not run true duals. If you look at some of my other posts, I explain why true duals are a downgrade.

On the Dodge, this guy give a valid example, but does not fully explain why this happened. For started, dual 2.5" is a very large system. It works ok on a car like a Mustang GT, but is known to be loud. On a Mustang with works better because both runs are the same length, and most setups have an H or X Pipe to help balance things out. Secondly, the CherryBomb Vortex has no packing material, it is just a chambered muffler, much like a Flowmaster, and as a result, it is designed to be loud, and it is extremely common for this type of muffler to drone, especially when combined with oversized pipe. The reason its quieter to run two mufflers instead of one is because you are running twice as much muffler, and you change the resonant frequency. And yes, running tailpipes in front of the tires is done mostly to make so you can hear it more in the cab, it will be much quieter with full length tailpipes.

When having a new exhaust system built, you need to take your engines size and power output into consideration, and you need to know what kind of sound you are after.

When choosing size, you need to understand that bigger is not always better. The rule of thumb is to use the smallest pipe size that will support your full power output. The 5.4L will produce about 320+ hp at the crank, which means a 2.5" exhaust will support the full power output of the engine. Of course bends in the pipe and length of the pipe can restrict the flow a little, so stepping up to 3" will not hurt anything. The real restriction is the factory muffler, and the manifolds, most the muffler. If you replace it with a correctly sized straight through type muffler, you can see descent gains, but mostly what you are going to get is sound, and lets be honest, this is what most people who get a performance muffler are really after.

If you run a dual outlet muffler, run dual 2.25" for the best balanced sound. This is slightly larger than 3" single, so it is more than large enough to support your flow, and will sound pretty good. If you run larger than needed, you cause the exhaust sound waves to collapse, which does deepen the tone. Sometimes this is desirable for some, but it also increases the risk of droning. A dual 2.5" is like have two pipe organs coming out your truck, your engine will hit a certain RPM, usually at about 1200 - 2000 RPM and they will start vibrating.

If you run dual 2.25" and then run larger tips, you can get some of the tone depending of the 2.5", without the droning. However, running 4x4" tips in my opinion is excessive and I don't think it will look that great though that might depend on what kind of tips you are going for. If you are going to run 4 tips select ones that have a smaller diameter, or at least a smaller internal diameter. A double walled tip can be 4" on the outside and yet a more modest 2.5 or 2.25" inside. This in my opinion also presents well.

Now on to muffler choices. At the end of the day this boils down to preference. My personally favorite is the wickedFlow MAX. It is a straight through design with fiberglass packing and quiet steel casing. I have used them for years on my own vehicles because I found them to be more classy and smooth sounding than a Magnaflow. And they will control drone under the exact conditions that a Magnaflow will cause it. I currently use these on all four of my personally vehicles, my 1997 Ford Aerostar 4.0L (dual tailpipes), my 1996 Ford Taurus (dual tailpipes with dual mufflers, much louder than the Aerostar because the size is larger and there is little tailpipe behind the muffler to help the muffler do its job), a 1987 Ford Thunderbird Turbocoupe with dual 2.5" exhaust dual mufflers (this sounds awesome), and my 2000 Ford Focus ZX3 (I replaced the stock muffler to make the car better sounding while being overall quieter and less raspy sounding than stock). So I have experience with these. I previously used Magnaflows on two of my vehicles, both had problems with droning while cruising. To me the difference between a Magnaflow and a WickedFlow is like the difference between a Mustang GT and an Aston Martin. Both can be loud and aggressive, but the Aston is more composed and refined. Not saying one is better than the other from that standpoint, I'm just trying to illustrate the different merits between the two. One is going to sound slightly raspy and untamed, the other is going to sound smooth and refined.

Here is a quick vid I did of my Taurus LX
WickedFlow Max on 1996 Taurus LX Wagon 3.0L Duratec - YouTube

and here is my Aerostar prior to converting it to dual tailpipes. It is louder and better sounding with dual tailpipes, but still retains that composed smooth sound.
1997 Ford Aerostar 4.0L AWD with WickedFlow Exhaust and Tru-Performance Cats - YouTube

 

In my case the runs were identical like a mustang as well, I have no underbody tanks (propane tank is in the box). As for the quad vs. dual tailpipes, it was huge for sure especially for the engine but the cause of the drone almost seemed to be reversion between the dual outlets in each muffler. Pretty sure reversion was the term I wanted there anyway. LOLn

Edit: I just re-read again, If you did true dual 2.25" with an H and ran a couple dual out mufflers with 2" tails it may breath well and not drone too badly? The other option would be single tails to the rear and a Y with the 4 tips attached.