96 LT1 with bad cats.. need help
 

hi all im from south jersey.. audubon to be exact.. just joined this community.. seems liek a great place.. anyway i have a 1996 Firebird Formula M6 with 107,000 on the car, ive had it for a year.. about a few months ago it started running like butt and the check engine light went on.. it was the cats.... now every route i look at is expensive. one place said 1000.. the next 800.... then my neighbor who does that kind of stuff said 350... also i was on summit and saw the magnaflow direst fit and all and the catco, how are they? honestly i world like to do a full exhaust on the car cause the car is stock cept for a k&N CAI, cept i want it to be leagal.. whats the cheapest route? its goign to be my everyday driver so im not going to go with full length plus off road y.. i posted on ls1.com and got no help at all thanks!

Pacesetter emissions longtube headers with their catted y-pipe and the cat-back of your choice. Should run between $800-1000 for parts depending on the catback you choose

edit: you could also do mid-length headers which will knock a couple hundred off the price but IMO if you're going to do headers you should just do the longtubes

that sounds exactly liek that route i wanna take.. where can i find this set up???

i got a catco high flow cat off ebay for 60 bucks it made a helllll of a difference in exhaust noise it sounded great. but i cant pass inspection now lol

welkl i jsut called pacesetter.. then dont offer a catted y.... they said that the mid length accomodate to the stock cat location.. how can that be so when the driver side cat is right under the manifold????

i think i came to the conclusion im gonna buy the magnaflow direct fit cats.. but it says in the notes for the driver side "no provision for 02 sensors"... what does that mean???

damn...i could have sworn they used to offer a catted y

In that case i'd go with the MAC mid-length headers and catback of your choosing, or try and squeeze a pair of cats onto the pacesetter offroad y

The mid length tubs are the same size and shape as the stock manifolds. It gives you better exhaust flow, while still being able to keep the Cats in the stock locations. It is illegal to move cats from their stock location OR replace a known working cat. That is why longtubs are "illegal" for our cars, since we have to move the cat to where the y-pipe is. Most catted-y's are "high flow", which is less efficient and there for you prob wont pass emmisions with your car, you have an OBD-I diag port so they require your car to be put on the rollers. LS1's have an OBD-II port, so as long as they see the cats and there is no "SES" light on the dash, and the computer says everything is ok, LS1 cars are normally good-to-go.

I did research, and mid-length headers are really no better then ur stock exhaust manifolds. The "bottle-neck" is the stock cats, so no mater how much the mid-length tubes flow, the end result is the exhaust isn't flowing anymore faster or with more volume out of the car then the stock cats are gonna let it. All u did was move your bottle-neck from you manifolds to ur cats. if you put on a free-flow exhaust (i.e Magnaflow, Borla, SLP Loumouth I & II ) ur removing 1 of 2 bottle-necks. if you want headers, do longtube, if your worried about inspection, replace your cat with an OEM one and get a free-flow exhaust.

That means there is no O2 sensor "bung" (the hole the O2 sensor screws into) on the unit. I think our cars have a total of 4 O2 Sensors. 1 before and 1 attached to the cat right behind the "honey comb" on each side.

I would stick to OEM cats and forget the "high-flow" ones. High-flow cats don't flow that much more then OEM. OEM ones aren't as restrictive as most people think. I didn;t believe it myself until i did some reaserch and saw flow comparison charts from un-biased ppl. You will also notice that some cats say OBD-I & OBD-II compliant. That just states it shouldn't set off the SES light on your dash; that it is compatiable with your computers stock settings. That DOESN'T mean it will pass emisions. Save urself the headach.

my neighbor work son exhaust for a livign and said he can cut and weld new ones in for 320 for me.. is that a good deal???? cause if so ill just go that route.. i thought maybe the magnaflow would be easier but without the provisions.. how is that even going to work??

i know ppl that will pass me as long as i have em on.... are there an catted y's out there???? i cant even find any period

yea, thats a pretty good deal. You can weld bungs into it, but then you need to get the correct bung and modify the cat which will proably void the warrenty of the cat shall something go wrong. if he can take a cat and fabricate the front and back connectors to work with your stock setup, then have him do that. Just make sure they are emisions legal cats.

Basically you can't have ur cake and eat it too. You can get LT's and a catted-y and take it to a shop for a private inspection. Normally if they see the emisions stuff is there,and you dont have an SES light on, they don't bust your balls to much. You can't be fast and legal, not in NJ. lol.

If you go with LT's, then do a catted-y and a free-flow exhaust. If you dont want to get LT's; save your money and keep the stock manifolds, OEM "regular flow" cats, and buy a really nice free-flow exhaust and have a cutout installed.

i believe KOOKS sells them seperate from their header package as well. i think it is about $700 or so. If you do that, get the HOOKS headers and catted-y package. don't mix and match parts if you dont have to, that can just lead to nothing but problems, and your not saving any more money. i believe the whole package runs about $1,800

i guess that is my best bet then.. i was think ill get them welded in now.. save up.. maybe get some shorties.. and i want the slp lm1.. right now i jsut have the K&N CAI... other than that and the exhaust... how could i get mine down to like mid 13's???.. even better question.. what does my car usually run stock

thanks sooo much nightrydass.. u have helped me more in the past couple hours than anyone has in the past yr on my f body.. i really appreciate it

np, these guys here have helped me out so much it isn't even funny. they really know their ***** on this forum.

As for as what ur car runs stock, im not sure. I wanna say high 13's, low 14's. I wouldn't do shorties, i have never seen them on any car execpt a stock C6 ZO6. get LT's or don't bother, u'll be disappointed for what i have read and researched on.

to make it faster, get a nice exhaust, SLP intake w/ K&N. nice set of 3.73's or 4.10's (if your car is auto, id stick with 3.73's. If it is also your DD, 4.10's might hurt u on gas). fine someone who does OBD-I tuning and have ur car tuned.

matter of fact Gm High performance Parts Magazine has a couple issues about souping up a car just like yours. you should check it out.

The issue with moving cats is because they are designed to work efficiently at a particular temerature, and moving them further down the exhaust hinders their ability to stay at said temp. This is why longtube headers are not emissions legal.

As a side note, this is why the A.I.R system is in place on some cars- to heat the cats up faster on startup.

yeah mines an M6... would i be ok with 410s? or should i jsut get 373s? our car stock is what 342 or somethin? with an m6?

I just noticed you have a 96...that means you're obd2 so as long as the dmv sees cats and the pcm doesnt throw any codes you're good to go. What I would do in your situation is run the Pacesetter emissions longtubes with offroad y-pipe and the catback of your choosing(i prefer borla) and getting a 3" stock replacement cat gutted and welded in the intermediate pipe of the catback and calling it a day. The DMV will see that it has a cat and provided you get the rear o2 sensors deleted via a tune the car will pass without a problem.

also to give you an idea what longtube pacesetters with no cats and an open borla sounds like here's my old car:
http://i62.photobucket.com/albums/h9...olina1_089.jpg

As for what the car will run you should be able to run mid-low 13s with just a full exhaust. I went 12.7 with exhaust and gears in my 95

damn man that thing sounds sick

Random technology offers a "high flow" Y-pipe. Slightly larger pipes and two high flow cats for about $550 that is a direct blot in and should yeild about a 10 HP gain ( not very exciting ).

Shorty header kits are all going to run over $1000 as the come with y-pipe and cats. If you go this route the MAC headers are a good unit for the price. you can expect a 20-30HP gain.

Long tube headers will certainly give you the most HP, 30-40 HP gain, but you may have trouble getting thru inspection and ground clearance can be an issue if the car is lowered.

Just some options to think about.

You can replace a working cat, but only if it has 80,000+ miles on it.

- Justin

yeha i got the cats fixed yesterday and the car is running greeeat