I have a 2005 screw with 5.4. Now all I have is my muffler cut with a y pipe. My question is if I get high flow cats and a muffler if Ican make it lounder? And which S/I, D/O muffler do I need. I still want it Loud. Also would like to know how to make the high flows work with the O2 sensor since they dont have a bung for it in the cat itself.

 

If you have 4 cats, just cut the last 2 big ones off.

Either a Bullet or a Magnapack should suit you. Just be sure to have it exit some where. No reason to dull the overall sound by dumping it.

 

Will cuttin the back 2 off make the engie light come on or make it run like crap? Its going to be rean all the way out im not dumping it

 

No, there won't be any CEL. That problem is with the 97-03's, not the 04-05's.

 

does the 05's come with 4 cats? is the magna packs SIDO?

 

more then likely u have four cats and a magnapack is a round body single in single out, just slap on a y pipe after it to transit into duals

 

Half do and half don't. Get under your truck and check. The first set are really small and pretty far up there.

Like fine_style150 said, add a Y-pipe after the Magnapack so it can have dual exits.

Here's a link to performancepeddler.com. Everyone here uses it because they half awesome prices and free delivering. Just be sure to use the code "clubgp".

http://www.performancepeddler.com/de...CT_ID=MAG10416

 

I have a 04 FX4 w/5.4 and I'm thibking about going true duals but was told my gas mileage would go down due to not enough back pressure. Anybody got any input on this?

 

^^ you'll be fine, just run true duals

magnaflow 94106 high flow cats
magnaflow or ebay x pipe
2 magnapacks, bullets, mufflers of your choice; not flowmaster
2 stainless tips

run 2.25 for torque or 2.5'' piping for higher end

 

I can see 2 from under the truck one under the driver and one under the passenger. Is there any that you cant see under the truck? If I take then out what do I do with the O2 sensor?

 

If you only have 2 cats, then just cut them out and swap in a pair of 94106 hi-flow cats. Have the O2's mounted after the new cats.

If you want true duals, go for 2.25" pipes, X-pipe, and mufflers to increase your low end.

Oh and back-pressure is a myth. Check out my guide that's stickied for references.

 

Would it sound like crap if I left the cats off and put a magnapack before the y pipe? and would a CEL come up?

 

Just do whats listed above and you WILL be happy

 

WTF are you talking about? Let me draw it out for ya.

 

lol i like the drawing, im prone to visual learning and understanding myself. lol