Ericdm

iTrader: (1)

Im going to start modding my stock 04 auto 5.7 gto and i want to begin with the exhaust. I want to get rid of all 4 cats and replace the stock mufflers with loudmouth 2 resonators? Any thoughts on that set up? Also do catless midpipes replace all 4 cats and will they bolt up to the stock manifolds?

I am needing to find a midpipe that deletes all 4 cats and hooks up to the stock manifolds as i will be waiting on the headers.

Any thoughts help advise is all appreciated my car is my daily so i am wanting to do full exhaust headers back, intake, 160 stat and a dyno tune at speed inc. with radials hoping to hit low 13's high 12's

derbs

iTrader: (3)

If you getting headers just wait on the midpipes till you buy them so your not doing it twice.

GTO Jimbo

You have 2 cats, not 4.

Headers-->catalytic converter-->resonator-->muffler




LT headers and catless mids will replace the cats and resonators.

I have not heard the loudmouth 2 in person so I can't comment.

Ericdm

iTrader: (1)

also this is my daily and not a race car is there a huge difference performance wise between shorty headers and long tube headers i was looking at the pacesetter long tubes with there catless mid pipes? seem to be good quality for half the price of other headers out there.

also once i have my intake and full exhaust (headers back) will i NEED a tune right away i know i will greatly benifit from on even stock cuz from the factory the computer tune is way held back, but do i need one is my motor or anything at risk if its not fine tuned right away.

Thx for all the help guys im a newb to gtos only had ls1 and lt1 trans am's

BAAD LS2

iTrader: (5)

Get LT's but don't get pacesetters. They are junk. Get yourself a set of Kooks or ARH, something stainless if you want them to last.

B4Cya

If you're going to be installing parts one at a time and want to get rid of the cats first you can go with JBA catless mids then add the JBA shorty headers later on. The JBA set up is stainless too.

You're going to need a tune to take full advantage of any exhaust set up you go with anyway you look at it.

Ericdm

iTrader: (1)

Will the jba catless mid pipes bolt up to the stock manifolds?? and also will the jba catless mids get rid of the cats and resonators??

Is there a big difference in power between the jba shorty headers and a set of long tubes other than the 400-500 dollar price difference?

B4Cya

They bolt up to stock manifolds and delete the cats and resonators. Longtubes will make more power than shorties/mids but the difference is negligible unless you're running a big cam or forced induction.

jamesSS

Just save up and buy it once, do it right the first time. You will be much more happy. I dont think your first setup idea will work, the diameter of the piping is different. Look in the for sale section for a used catback, slp LM's go on, then come off after a cam is added since its to loud for most peoples taste. You will need a tune after switching to catless cause you will throw a few codes. And id skip the 160 degree t-stat. does nothing really, and your tuner can optimize your current settings for your driving needs. Id get the catback first, then the headers. Intake doesnt do much either, you be better off getting a K&N drop in and spending the $ on an under drive pully or start saving for a stall. That or upgrading your brakes wouldnt be a bad investment.

breze84

Pacesetters are fine for Longtubes, dont listen to some of these idiots like DAVE.... lol, anyways if you want to know a better place to get dyno tuned send me a PM... I dont want to name a non sponser in place of a sponser... You in the Chicago area??? If so check out ChicagoHoldenConnection.com

george g

iTrader: (12)

jba shorties and catless mids and a good tune with drag radials will get you in the low 13's.

402GOAT

iTrader: (2)

I've got the pacestter longtubes, catless mids, the 2.5 inch factory neckdown(where your catback bolts to the mid pipes) removed and one chamber flows with dumps right before the axles. I love it and it sounds awesome. I get alot of compliments about the car everywhere I go. Oh, I did get headers and mids coated by jet hot. Well worth the money.

george g

iTrader: (12)

when are you looking to buy,might be selling my shorties and catless mids soon.

crimsongtp

iTrader: (2)

Hey i have LMII!! For me i think its just okay. i have it with the stock X pipe that it comes with but i think i should have opted for H pipe. It sounds a little Euro to me but when you get on it the LS1 muscle comes through