2002SilverZ28

iTrader: (3)

i currently am running kooks lts/ORY/GMMG/cammed.......it sounds great but a little too raspy for my liking.

i am thinking about adding in a cat or cats to get rid of the rasp and was wondering if anyone else has done this to this setup or with a similar setup?

what a good cat to use that will fit? what is the best location to put the cat(S)

let me know what you think.

ryanfx

iTrader: (2)

I went from an ORY with borla to a catted one... wayyy too raspy w/o cats. Um best cats if you want to gain that extra 1-2 HP and have too much money to keep in your wallet?

1.Random

Best cat if you dont care about that 1 HP loss over random and only want to spend about fiddy dolla?

Magnaflow

HD1911

iTrader: (13)

good lord, i have yet to experience this soo called rasp everyone is ranting about. I have mac mids and ory w/hooker catback and have never heard any annoying rasp or drone. Is it just something with LT's or what? sorry 2002SILVERZ28, just thought it would be a good time to ask.

ryanfx

iTrader: (2)

hooker doesn't have bad rasp at all It's also more-so with LT's yes

Fire-formula 93

iTrader: (1)

Trust me when it is there, you will know it. And IMO, it is disgusting.

dave70

iTrader: (2)

rasp is more pronounced with cat backs like the LM,GMMG,TSP RUMBLER because of the lack of a true muffler. but before you go through the trouble of cats try a cheap bullet muffler in the I pipe dynomax sells one for about $30 but it get's mixed reviews that is what i'm going to try with my LM LT ORY setup.

2002SilverZ28

iTrader: (3)

i am guessing that the difference is coming from the headers and the GMMG exhaust...which is really just bent pipe

2002SilverZ28

iTrader: (3)

like the idea of a bullet muffller...would be a lot easier to do.

losiguy

iTrader: (7)

My friend has Jet Hot LT's, Jet hot ORY with a dumped magnaflow bullet and it has no rasp. Sounds good actually?

ChocoTaco369

because then if it doesn't solve it, you're out the money for cats, the muffer and the cost of welding in the muffer, so you're effectively out 50-100 dollars. also, if you decide to put in cats anyway, now you have a bullet in your system that you don't need quieting you down unnecessarily...unless you wanna pay to have it removed, making you out even more unnecessary money.

IMO just get cats. from all the people raving about a catted-GMMG having zero rasp on this forum, you're basically guaranteed to be rasp free afterwards. plus, you'll have the added benefit of having no gas smell in your exhaust when sitting in traffic.

2002SilverZ28

iTrader: (3)

very good point ChocoTaco
i think that i am leaning towards doing the cats but my next question would be do i really need to have two?
all of the catted Y's out ther have one off of each header...but for the ease of doing it and just to get rid of the rasp i was thinking of doing just one after the ORY and before the GMMG....basically in the I Pipe
This wont cause any issues...right

ChocoTaco369

absolutely not! u will lose like 75 horsepower! one single cat CANNOT support anywhere near even a bone-stock LS1 engine. they simply can't flow enough. you absolutely NEED 2 cats. having one cat on an LS1 is like eating pudding through a straw - that's how hard the engine has to work to get the exhaust gases out. do not, do not, do not buy one cat. get 2 or get none.

ActionJack

I decided on Magnaflow cats and am having them installed this Friday. I hope it was the best choice. But truthfully I never considered Random, probably because it slipped my mind. Oh well...

Also, I have Mac headers and Y pipe with Magnaflow catback and with thew ORY I get rasp pretty bad and my wife hates the drone at highway speeds. But it has been fun waking my neighbors up when I start the car early in the morning.

2002SilverZ28

iTrader: (3)

i definately hear where you are coming from on this one and thats what i thought from the getgo....but i have talked with others that have brought up a good point>>>isnt there only 1 cat on a bone stock ls1 vette?

lastcall190

iTrader: (36)

No it's not the power factor, it's that that far downstream, the cat doesn't heat up to become effective. I'm also pretty sure there are two cats on a vette, but I may be mistaken. Before anyone says it, there was only ONE cat on the 93-95 f-bodies (excluding CA), but those were stock manifolds, not LTs, and the cat wasn't as far as it would be in this aforementioned setup. Good luck.

-J

ActionJack

Yeah the vette has 2 cats (and true dual exhaust) and as you said they are farther back. I think that is why some put the O2 sensor in from the C5 because the stock O2 sensor are made for the shorties. At least that is what I read somewhere here and I can vouch for throwing rear O2 codes after the header install but I never tried the C5 O2s, instead I deleted them.