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.

 

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
it had less "filtery stuffs" inside with wider openings than the one that came stock placebo effect probably gives me 15hp!!!1

 

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 you can probably find them, and cheaper
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?