Man I tell ya, finally figured something out today that's been buggin me. I've got my '02 and my dad has an '07. For a while, we had the exact same exhaust; stock from the muffler forward and a SIDO Flowmaster (exact same one) with dual pipes. His truck friggin always sounded better and significantly louder than mine. I never could figure it out and I always hated that my truck didn't sound like his. I always just chocked it up to being a 2V motor vs a 3V motor thing and left it at that; it is what it is.

Well today I decided to look under his truck and lo and behold his only has 2 cats!! There's the difference! And what a significant difference it is. Can't wait to finish my system!!!

 

Get use to it, the 3v's do sound a little better done up right. But yea, 4 cat systems are a little overboard since your still within programmed parameters just running the two forward converters. That's some margin!

Flowmasters sound great with everything else in order. Made my 5four sound like a GT lol. I was running a 50 race series(not the SUV series) for awhile (still chambered). Loved the sound, but I was always on the muscle towing and it made that midrange flat spot a little more pronounced.

I ran a 4"x22" Magnaflow (race series) for awhile and just wasn't crazy about the sound. However, towing, -I could get up to speed, level off quicker. At times it felt much quicker, specially from the light, 3/4 throttle.

Went to a 9" Magnaflow, - same just a little mellower sound.

I'd like to try a Borla or Corsa next. Like the sound clips.

It may be easy to out perform the Flowmaster. Getting a better sound is a little more difficult.

Unless you @ 500 horse. Anything back there sounds good lol.

 

Putting 2 hi-flow cats in place of my 4 factory was by far the best money I have ever spent on my truck. It completely changed my exhaust sound. You will love it!

 

All trucks from 1997 to December 2004 had 4 cats. The 2 cat system was installed in Jan 2005+ models. So certain 2005s have 4 cats, others have 2 larger cats. Fun fact.

 

Interesting, because I know I've seen guys on here with trucks inside that range talk about only having two cats???

 

Yeah my other 2 fell off: devil:

 

Yeah I have a 2005 that came with 4 from the factory just lucky I guess lol

 

All of mine fell off. haha

 

I thought they went to 2 cats in 06+

My front cats are there but they don't have any guts in them.

 

In a closed up, shady shop !

 

All 4 of mine "fell" off so I replaced them with 2 high flows. I'm curious though as to if it will pass inspection. I have one coming up in another month. Can anyone shed some light on the subject? Thanks!!

 

As long as no light, your good bud.

 

^ yep

 

Or leaks! If they are pr**ks about it they could say "that hissing is a leak, and it needs repaired because it is under the cabin." A CEL doesn't illuminate with leaks past the cats.

 

I replaced my two fat cats with two maggie hi flows last month and it made a WORLD of difference in the sound. I love them and can't wait to get my PHP Gryphon tune now.