I have a 2007 ram 1500 with a hemi, it has flowmster 50 series SI/DO with a magnaflow y pipe. I was wondering if after market cats would make it sound better/louder? Also which cats would be recommended? thanks for the help

 

I may be wrong but I thought the stock cats are pretty high flow as is, so you might not hear or feel much of a difference...hopefully someone else will chime in here

 

Now if you were looking for some REAL improvement with your exhaust, I would get some long tube headers instead of cats. That would make a much bigger difference.

 

well thats what I would really like but I thought I read where weed put some on his truck or something and he liked them and made it sound better. I like your truck though, thats nice (KUhawkFan)

 

Are you in a state that has smog regulations? High flow cats are the way to go, if that's the case. You will not get any more/less sound. KUhawkFan is right. If you don't have to worry about smog, ace the cats and go long pipe. If you want a beefier sound, think about headers. I found a better than stock sound, when I added my CAI. Just some things to consider...

 

From strictly a CFM standpoint, the stock cats are pretty decent flowing. Cats today are not the highly restrictive cats of the 70s and 80s. A Maggy cat will yield a bit higher flow rate, but not enough to justify the cost of replacing a perfectly good cat. Now when your cats start to clog up on you, then would be a good time to upgrade to a Maggy.

As far as sound goes, won't make much difference, a little maybe, but not enough to notice much.

Headers will change the note a good bit as will a CAI. My headers changed the exhaust note to a much deeper one, kinda like you hear at the track from them big block V8s on race day.
If you want more sound and not have to spend a bundle, cut the FM50HD out of there (I had one, decent sound but not great - and they flow like sh*t) and put you a Cherry Bomb Extreme or Vortex in place of that muffler. You'll have the neighbors cursing you every time you pull out the driveway...

 

I just moved to Alabama, due to a job, and I really don't know the smog rules here yet. I wish i didn't have to have the cats period. So the cherrybomb vortex will still give some back pressure? The pacesetters LT's would fit? I have a 2007 1500 QC 4x4 hemi. what other headers are recommended? I know some will fit and some wont because of the 4x4. Thanks for the response

 

back pressure equals heat buildup due to the engine having to work a little more to overcome that pressure and push the exh out.

LTs will fit but will push the cats back some. I have no cats behind my LTs. Some shops dont mind pushing the cats back as long as they are there. Some will not move them at all. Some will remove them completely.