Cat vs. Cat and PreCat Need Help Fast
 

How much different will the sound be with the same motor same exhaust a Flowmaster 40 with 2.5" pipeing but with one setup have a cat and a precat compared to a setup with just a flowmaster 40 with 2.5" pipeing and just 1 cat?

well i have a free flowing pre cat, hi-flow cat and super 40 dumped at the back side (no tail pipe) it took m a while to like the sound, but if you know what exhaust sounds like on a v6, you will be happy.

i would change it all while you are in there. the last thing you need is a tired pre-cat going to hell on you and taking your new cat or cat/muffler, with it. :icon_twocents:

By free flowing pre-cat, do you mean you hollowed out the inside of it or did you buy a new cat?

I have a 99 Blazer with a FlowMaster 40 with 2.5" pipeing and im possibly getting another 99 that has a precat and a normal cat also. I think its a california emissions truck and I was going to do the same exhaust a 40 with 2.5" exhaust but I want the same sound. Will that precat made it quiter? I love the way my truck sounds. I love how V6's sound when done right and I love mine. Just curious dont want the sound to change

i did it all in 2 steps. step one was pre-cat/cat step 2 was muffler and dump tail pipe. i couldn't tell you what difference it would make :(

as for the free flow that is how it was described on the box :p
it had less "filtery stuffs" inside with wider openings than the one that came stock :icon_shrug: placebo effect probably gives me 15hp!!!1

:icon_playing:

Mind giving a link to where you got both of your cats at? My cats are starting to act up on me and I'll need new ones soon. Good excuse to get hi-flows. Throw any codes?

I got mine at a local miffler shop, Ed's Exhaust (sounds fly by night but there are like 6 of them and they have been doing good stuff sine the late 70's). I had to get mine out of necessity so I failed to do "research" as it is, but the invoce called em:

PART #610250, 2.5" OBDII W/02 Conv. $189.95 discounted to $68.15
and
Part #CS99006HM HM Loaded Converter $499.95 discounted to $278.15

with :icon_google: you can probably find them, and cheaper :icon_shrug:
again i NEEDED mine out of 'running vehicle vs. broke down' necessity so basically i catalog shopped for 45 minutes, BSed with the dude doing my actual labor and welding, had him cut me a sweet deal (quoted: $1110, supplied my own 02 sensors (x3) and gave the muffler jockey $40 cash for his troubles and got the whole thing for $590 all told. still a LOT more than if i could weld it on myself, and had shopped for parts prior to, but saving $500 never hurts)

"PART #610250, 2.5" OBDII W/02 Conv. $189.95 discounted to $68.15
and
Part #CS99006HM HM Loaded Converter $499.95 discounted to $278.15"
HOLY CRAP! Do you need that for emissions or is that a performance thing? All they do here is make sure you have no CEL and let you go!

BTW, I have read a couple times here of hi-flow magnaflow cats throwing a P0420. Around here all you can get are Walker stainless-steel standard 3-way cats, and they guy sellin' em says they do just fine. Ever heard of em? Cuz I gotta get one soon... gotta, not wanna. I'd love to do a hi-flow, but getting a code would suck and make me use those special words that we aren't supposed to say here... Let me know if you can find the brand, and if they have a good rep for not cracking.

Regards,

Thomas

Like the Magnaflow ones, I've heard good things and I've heard bad things about Walkers throwing codes. Like I said, no code on my Magnaflow when I put one on my Firebird until I blew the valve seals going to bigger rocker arms.

Im just trying too see if have a cat and precat would be quiter than have just a cat lol?