hello everyone. im a new subscriber and am looking forward to geting and exchanging info. my questios is about exhaust. i have a 02 f150 w/ a 4.6, my dad has a 01 f150 w/ a 4.2. we'v heard that the only way to do it is a 1in2out muffler. the muffler shop said 1 pipe off each cat would make it run bad, doesent sound right to me. any help would be appreciated

 

Hello from Ma. Welcome to the site. The folks around here have some excellent know how when it comes to these rigs, i'm sure
you'll get some excellent fixes for your particular truck. I have
an '04 so i'll be going catback duals when the time comes,
( i believe that's 1 in 2 out ) Again welcome and good luck with
your inquery...

 

If you want Flows go with the 430402 3inch in dual 21/2 out

 

Russell, Welcome.

Your exhaust man, sorry to tell you, isnt the brightest crayon in the box. There are tons of F150s with true dual exhaust.
The way most are done is by cutting out the y pipe then welding separate pipes on the 2 pipes coming from each side of the engine.

I have duals on my 4.6 and it runs perfect. It WILL run bad, however, if you put to big of pipes on them.

For your 4.6 put 2 1/4 inch pipe on it-unless you plan to mod it (chip, intake, etc.) then I would do with 2.5 inch.

For the 4.2 liter, go with 2 inch pipe-if its getting modded then go with a 2.25 inch pipe.

I know it seems like small pipe, but this way you will not lose any performance-which to big of pipe will do.

 

Thanks Bartak1, I was thinking that but wasent sure about pipe sizes etc. I appreciate your responce. Its nice to hear from someone that actully did it and know, not hearsay or assumptions..

 

i think when your muffler guy said that it would run bad, i think he meant that you'll lose a lot of low end torque by running true duals. in turn, you'll gain a lot of high end torque.

 

i just put true duals on mine with the elbow cats removed and the other 2 gutted,and i didn't notice much difference from when i had no cats and a flowmaster single in dual out with 2.25 pipe in place of the cats.i have 2.5 all the way back now with an h pipe