Reworking my exhaust (CAT suggestions, pipe diameter questions)

[flyboy1294]

Here is the deal:

I have a 98' k1500 with the 350 Vortec. As of right now, it has dual Flowmaster Super 44 turndowns on it.

I purchased some Hooker Long Tube headers for it, and am totally reworking my exhaust from the headers back because of this.

1). My stock cats are rattling, so they need to be replaced. Here are they cats that I am looking at: http://www.summitracing.com/parts/MPE-53006/. Are those okay? I know the Magnaflow SPUN cats are suppose to be good, but unless there is a major difference I do not want to shell out the extra money. At the same time, I am not wanting to be a cheap ass on this project. If I need the extra expensive cats, I'll buy them.

2). Will 2.5" exhaust tube through the whole system cause me to lose low-end power? My headers have a 2.5" pickup, and my mufflers have a 2.5" pickup as well (I think.) Also, if 2.5" pipe is good, should I go with CATS with a 2.5" inlet/outlet?

If I need to do 2.25" pipe I can, but will I run into issues using it with the 2.5 pickups? And if I need 2.25", should I get the CATS with 2.25 in/outlets?


Thank you all for the help.

 

[stroker52]

i say dont cheap out on the cats if you go with cats. 2 1/2 is ok a little on the big side but if you go smaller you will be ok also.. if it was me i would do 2 1/4 from the headers back to the mufflers then from the muffler go 2 1/2 out the back.. if you keep the turn downs go 3" and you will not get the pop sound it will sound deep. also put a X pipe about 2 foot away from where the pipes meat up and this will help so much on mid range power...

ive run something close to what i telling you and loved it..

 

[flyboy1294]

i say dont cheap out on the cats if you go with cats. 2 1/2 is ok a little on the big side but if you go smaller you will be ok also.. if it was me i would do 2 1/4 from the headers back to the mufflers then from the muffler go 2 1/2 out the back.. if you keep the turn downs go 3" and you will not get the pop sound it will sound deep. also put a X pipe about 2 foot away from where the pipes meat up and this will help so much on mid range power...

ive run something close to what i telling you and loved it..

I have true duals on it now is the thing. Should I install the X pipe and ditch my true dual setup?

 

[sewlow]

The X will really help with the low-end performance. It actually makes power, when installed in the right spot. I noticed the difference as soon as I left the exhaust shop. Sounds better @ an idle, too.

 

[flyboy1294]

Alrighty I will look into it.