I own a 2002 F15 4.6 liter. I want a Magnaflow system, but i want dual side exits on the same side, like a H.D. so, i am going to buy a muffler and have a shop fab a system. What muffler do i need from Magnaflow? It would be si/do, and i probably want 18" long, but not sure what size/which one. Can anyone help me out, if you have done something similiar?

Thanks!

 

I just did this exact same thing two weeks ago. I have a 4.6 as well.

I bought a 14" Magnaflow- single in, dual 2.5 out and had Meineke run short dual pipes out in front of the rear wheel. Sounds good. Not obnoxiously loud, but nice tone. If you run the duals all the way out the back, the longer pipes and more bends really quiet the muffler. (My buddy did his at the same time and he has the 5.4, his is duals out the back- you cant really tell he has had his exhaust changed)

If you want LOUD, dont go with a Magnaflow

 

I really don't want loud, the g/f probably would not be happy, therefore, i would not get to be happy...

I was debating between the 18" and 14"...

anyone else?

 

only real difference is that 14" will be a little louder

 

Also consider the body size as well as length. Magnaflow has 4x9, 5x8, 5x11, and I think one real small oval as well as several different diameter round bodies. Not all come si/do but check the website for a si/do in the different bodies as well as length offerings. Just like length, the bigger body muffles things down more. I run si/so and when I had a side exit I switched to the 5x8/24-inch from the 5x8/18-inch but mostly b/c towing was annoying. Hard to give a suggestion on sound as everyone has their own opinion of "annoying" but assuming you keep the tips fairly small the 5x8/18-inch is quite a bit louder than stock yet not too annoying when you are taking the lady and friends out.