Hmm.. I have a Magnaflow true dual setup with a 5.4L and I love the sound. I've never once heard it snap crackle pop like most of the exhaust clips on youtube. I have 2 14" round body mufflers, x-pipe, and 18" 3.5" tips, all on 2.5" piping. As far as performance, I can't say as to whether or not I "lost" low end torque, but it sure doesn't seem like it. My truck has excellent throttle response with the AF1 3.0", X3 tunes, and 4.56 gears, it's almost as touchy as my Honda Civic. As far as noise, the truck has a nice deep low rumble at idle, and is more than tolerable at highway speeds. I hardly push the truck over 2500 rpms driving around town, but anything above that and the truck starts to roar. I get compliments on the truck all the time and have no complaints with the Magnaflow setup. If your concerned with rust, just spray the piping with high temp spray. I sprayed mine all black and there isn't a single bit of visible rust in the past 6 months since I had it installed. Total price for all my parts and labor was right about $400, ($180 for the mufflers, x, and tips + $220 for the piping and labor).

There's an exhaust clip of my setup in my signature, it was a little windy that day, but you get the idea.

 

Oh definitely, the 18" Magnaflow will be much quieter than the Flowmaster. A broken in Magnaflow 18" is just right, not too quiet, not too loud, respectable note that keeps the peace.

When having a dual outlet muffler, its always best to have a thicker intermediate pipe to equalize the velocity and scavenging more. 3" from the Y pipe into a 3" muffler will be very free flowing, while exiting through dual 2.5" outlets will flow it out equally with enough force from the 3" pipe. You should not experience any loss at all with any 3" single in 2.5" dual out set up. The scavenging is all correct and it all agrees with it. If you got a 2.5" single in 2.5" dual out you might not have the tone you expect, there wouldn't be enough pressure from the midpipe to push the exhaust note/gases through the same sized tailpipes fast enough.

Here is a video of an 18" Magnaflow. http://media.putfile.com/18-magnaflo...-on-46-04-f150


Mine never snaps, if it does I never heard it, but it will crackle slightly when reved just right, or downshifted, and it will pop when also downshifted, of overdrive de-activated. Going down a hill is awesome, you can definitely tell its a dual muffler system, sounds incredible, and its actually starting to drone on me a bit like my old Super 44s did..

 

I just picked up the Magnaflow 16614 today from Performance Peddler, awesome price under 400 out the door!! All of my research led me to this system. All stainless and Dyno tested ... cant go wrong (i think)

 

Darren,

I realize this is getting a little too in depth for a "which muffler should I get" thread, but now I am curious!!! At a given rpm, lets assume there is a constant exhaust velocity being emitted by the engine. If that exhaust is pushed through a 3" straight pipe, it will be moving slower and have less pressure than if that same exhaust was to be pushed through a 2.5" straight pipe of equal length. I can see where the tone may change a bit due to the change in velocity. Do you think the 3"SI/2.5"DO would be louder or quieter than the 2.5"SI/2.5"DO? You had mentioned that 3" from the Y to a 3"SI would be ideal. I still have the factory 2.5" piping from the Y and all of the way back to my current 3"SI FM 40 which I would rather keep (the 2.5" pipe, not the FM) instead of paying for several feet of new 3". So is there really any benefit to my current 3"SI as it is fed 99% of the way with 2.5" pipe anyway? It was just stretched up to 3"OD to fit inside the 3"SI.

 

For SI/DO, you will want 3" in 2.5" dual out. 3" intermediate pipe is better for velocity as the gases, sound, and pressure is pushed through the thicker pipe, which is forced into the muffler to be broken up evenly to flow out dual with a clear, rich sound. 2.5" with dual 2.5" exits wouldn't have enough space for the flow in the intermediate pipe and going dual from the exact same size it was, will cause a crackle/pop and not such good throttle response.

 

Thanks for all the help, just ordered me up a Magnaflow 3"SI/2.5"DO 18" PN: 12288 from performance peddler.

 

Good choice, enjoy!

 

Just completed the install about an hour ago, the system went on great it only took an hour and ten minutes. it sounds nice, deep throaty sound with only minor interior noise. slight power increase major coolness increase!!!

 

Congrats. Good to hear you are pleased with your choice.

 

Is there a page with a collection of these systems with dyno numbers?

I'd love to compare numbers.

I've got an '07 FX4 5.4L that's 100% stock. Not quite sure where to start.

 

I have an 08 f150 4x4 .. was debating between Cherry bomb vortex or cherry bomb extreme... then i heard a lot about the flowmaster 40s and 44. I use to have an 03 f150 with just a flowmaster 40 on, and it sounded ok..but wasnt loud enough for me.. Any suggestions or info on the super 44? I want performance and mean loud deep sound. Any suggestions would help...

 

Super 44 will get you more of the sound you're looking for than the 40. True dual super 44's will sound awesome, though.

 

The Super 44 will sound much better than the 40 series, and those Cherrybombs too.

 

Anyone heard the Magnaflow SI/DO next to the Roush legal version? Which is louder, or are they both pretty close to the same?

I had a Magnaflow si/so on my '03 and really liked the sound but want to go with a si/do this time. I don't want it very loud, just a nice grumble. I like the thought of the Roush, but I'm actually worried the off-road would be too loud and a little worried the legal version might be too quiet?!?

 

Way to bring up an old thread!

The Roush Legal and Magnaflow cat-backs sound very much alike.

Roush: http://www.youtube.com/watch?v=yuzx1VKGnZQ

Magnaflow: http://www.youtube.com/watch?v=RfPb2d9k-Wo

The Magnaflow video is close to the tip and a SI/SO but the sound of it is generally the same.