sandman63

Just put a SLP LM system on my comptelely stock 94Z, i left the cat.. wondering if i took it out would it make a big difference in noise an if so good or bad? thanks.

95z28man

I just got done installing Pacesetter LT's, y-pipe and SLP Loudmouth. I have no cat on anymore. When you rev it hard it makes a really loud ripping sort of sound. Very aggressive. When driving, its deeper and throatier around 1-2500 rpms, if you give it gas hard it will rip right into a scream. I personally like it, but it up to what you want. Definately could scare a bystander if you cruise by and hit it hard near them. Picks up very fast with no lag. I love it.

v8pwrdz28

no cats =).

00Z28SS

I also have LT's, ORYP, and Loudmouth. I asked the same question that you are. I'd say 90% of the people who responded told me to get highflow cats on my ypipe if I'm going to keep the loudmouth. Then I went to LS1sounds.com and listened to a couple different setups before I decided to go with no cats. I personally love the sound of the set up, but it is definetely obnoxiously loud.

2000SilverLS1

i'd keep the cats, if you remove them your car will sound like a duck. or at least mine did.

urbaNHunter44

that's because you have an LS1. LT1s sound alot different. No cat = sweet!

green.Z

I can speak from experience here. I took my cat off for about a year, then put it back on. It is awesome sounding w/o the cat when you're on the gas, but then when you let off, it sounds like crap. It like pops and crackles, not good. Even the time between shifting gears when you let off the gas sounds bad. I started getting in the habit of leaving my foot on the gas between gears to avoid it.

With the cat back on now, it is indeed much quieter, but it still sounds awesome. And doesn't have the bad "off the gas" sound it did before. Yours may be a little different since mine is the Flowmaster. I still get compliments from total strangers with or without the cat in place.

1quickTA

I LOVED my LM with cats and stock manifolds. I HATED it with no cats and headers. I dont know what no cats and stock manifolds would sound like, but my vote is leave the cats.

95z28man

I think if you take the cat off and get a good tune it will eliminate or at least reduce any popping or crackling, I have yet to tune mine and it probably wont be tuned for a while. I'm still in the break-in stage so I havent opened it up too much but the little bit I have it hasnt popped much really.

JaysGone

Its raw fuel thats making the popping noise not much you can do about that. Leave in the cat not much difference HP wise if any actually. I just put my stock system back on after 3 years with a LM and or chambered stick. Im actually enjoying the car again. Quiet, feels better, less noise, no cops looking my way etc. Milage went up 2 per gallon, overall feels like a new car with original catback.