530transam

iTrader: (2)

ok my cousin really confused me tonight. A few months ago i bought long tubed headers, an off road y-pipe, and 2 high flow cats. My question is how do these cars come from the factory? because i was showing my cousin the parts and he said "if the headers go to a single y-pipe then where does the other cat go?" and i was baffled. i really dont know. I knwo theres two though from the factory right? but the Long tubes have flanges that bolt directly to the y-pipe. There doesnt seem to be a logical place to put the carts lol. Do you really put both cats after the y-pipe? From the factory are the cats the next thing after the headers? like the headers dump right into the cats? did i mess up and buy a non-cat set up? cause thatd be bad since i live in Ca. Help me please im so confused. if someone could show me a diagram or a picture of the entire exhaust system from a factory fbody id really appreciate it i think it would really clear things up for me. A step beyond that would be a pic of how my set up is supposed to be. lol. So i have long tubes, then a y-pipe, then two cats, and then a cat back system. So where the hell do my cats go? Am i over thinking this? By the way its a 99 trans am. Ls1 and all that stuff.

robdawg13

Off-road y-pipe means no cats.

Ping King

iTrader: (20)

cats go after each header. You bought an off road y pipe. youll have to cut the pipes and weld or clamp teh cats on.

Weezzer

Any aftermarket Y pipe that comes with cats and doesn't locate the cats in the exact same original position as the factory cats is still an off road Y pipe. Its not legal as its a violation of federal law. While not all states currently enforce this, California is one state that does and he will find this out when he goes to get it inspected.

There is a thread that was posted not long ago from a guy living in California, they stopped him for an exhaust check and they fined him something like $11,000 for having the two cats out of location. He is still trying to fight it. I've heard the fine can be up to $15,000 max. per cat.

BlackScreaminMachine

iTrader: (17)

CT has really strict emissions, the inspectors look sometimes, really only if it failed.

Stock cats fit up into the engin bay/engine tray, I just took all mine out, When the snow melts I'll try to get you a pic.

Ping King

iTrader: (20)

yea..youre playing with fire on this one. ive never been to cali...but ive only heard stories. The person above is right in respect to moving cat locations.

lsx24

iTrader: (45)

The cats go after the headers, in the ypipe. 2 on both sides. If you already bought a ORY, you would have to have the ory cut, and cats welded in. Should be a piece of cake for most muffler shops. Thing is clearance. The ypipe is the lowest point in the system.

99Z28LS1

iTrader: (4)

i ran cats with my Flowtec LT and ORY, but the cats had to but fabbed in there. i ran LT, ORY w/ cats and 3" back to CORSA cat back and it sounded nice, but got rid of the CORSA for STS and removed the cats for fear of loosing the turbo

530transam

iTrader: (2)

should i just trade the headers and y-pipe to someone for a set of short tubes and a legal y-pipe?then would my cats fit in there and would everything be legal? is it a fair trade? if i put up my long tubed headers and ORY for sale together, what should i ask for them? i believe theyre pacesetter ceramic coated headers and an slp ory. what are they worht? i got them both for $200 which was a ridiculous price. I practically stole them huh?

98redM6

iTrader: (39)

If you plan on staying legal I would sell the long tubes, y-pipe, and high flow cats and just buy shorty headers. Most people go with jba shorty headers or edelbrock shorty headers. Don't change the stock y-pipe or cats since you'll only see a very small or no gain from it.

lsx24

iTrader: (45)

Why not install them? Have a muffler shop weld in the cats to your current ypipe, and then run them with pacesetters. Can't get much more bang for the buck than that.

530transam

iTrader: (2)

i need a new cat to smog my car and the cats i bought ARE legal. So i plan on keeping them. Is there enough room to have them welded onto my stock y-pipe AND put longtubes in?

300bhp/ton

We've been here before.

They are in CA and advising them to run Lts is not the right thing to do and really quite selfish.

300bhp/ton

ok several issues here.

First off LT's are illegal in CA this is because they move the location of the CATS. Take a look at your Lt's and see how long they are, stock manifolds are nearer 8" in length. So no you can't really have lt's and a stock Y pipe.

The stupid thing is that on a sniffer test a car running LT's and CATS is just as clean as any other, but the idiots running CA evidently don't understand this.

This means if you run LT's and CATS you will find it hard to pass a visual inspection, either at a test station or if you are pulled over.

Some people do get away with it, but most get caught at some point and potential fines IMO out weigh the possible HP gains.

So sadly running any form of LT in CA is not viable. This combined with other emissions regs which limit cam chioce mean running a high HP n/a setup in CA just isn't going to happen easily and not legally.

My suggestion is sell them and stick with a nice catback and stock exhaust manifolds and Y pipe. You could swap to high flow cats but the gains will be small.

Shorty headers are legal in CA, although only CARB certified ones if you really want to be fully legal. Sadly you'll see almost no HP gain with shorty headers on a n/a setup.

The technical reason is that the stock manifolds actually flow pretty good, certainly good enough for most n/a setups. Scavenging is where LT's make power, but sadly shorty headers don't scavenge within the LS1's rpm range.

This means shorty headers are generally worth 3-5rwhp.

So for n/a I say spend to money on something more worthwhile.

If you plan on boost (turbo/supercharger) then shorty headers will work very well, this is because scavenging isn't important with FI (forced induction) and the increased flow of shorty headers will be utilised with FI where it's not n/a.

If you want big HP in CA I see only a few options:

1. Nitrous
2. Boost such as a Procharger (think the P1SC may even be CARB certified, but would need to check) or maybe a STS turbo
3. Larger displacement such as a 383ci stroker or a 402/408ci block
4. Buy a 2003/4 Mustang Cobra

With options 1 thru 3 you want to accompany it with sensible bolt ons (they will vary a bit depending on which route you go):

-lid
-CAI like a FTRA
-FAST intake
-Bigger TB
-underdrive pulley
-electric water pump
-tune
-good catback
-high flow cats

Also don't forget non engine mods such as:

-tyres (DR's)
-gears
-suspension and chassis mods like body mounted torque arm, LCA, SFC, etc
-stall if auto
-shifter if manual
-weight reduction

A good suspension setup can have a massive affect on ET's and ability to launch a car, so good for dig racing. It won't have any affect on trap speed however.

lsx24

iTrader: (45)

There are tons of people running LTs in CA. How do you think that is? Automatically saying it's illegal and recommending shorties is plain unimaginative. Now, whether you want to take the risk is up to you, but finding a place to smog with LTs is not hard. I lived in CA for over 8 years with their smog bullshit, and you just have to find the right place. If you are summoned to a ref station however you are f*cked. Time to revert back to stock manifolds for the test lol.

530transam

iTrader: (2)

Ca sucks thats for sure. I know of a place where he'll pass me no problem but i dont know of a place to get them installed. I dont know what to do. I do plan on eventually turbo charging my car so maybee ill just trade my Lts for some shorties and sell my y-pipe and use the facotry y pipe with my high flow cats and shorty headers. Aside from not much power gain, can i expect a change in axhaist note with shorties?

GTObsessor

iTrader: (2)

Couple things to clear up for you guys in this thread as forementioned information. The fine in CA is $1,500 for each cat missing and the P1SC is CARB legal, hence legal in CA. The D1SC is not. On the books in the state of California, ANY modification to a component that affects airflow reguarding the intake or exhaust systems of a car is ILLEGAL. Sucks, huh? Thats why you just uuh... don't listen or stick with your stock car.