Does the stock cat 'bolt' to the y pipe?

[grayman]

I could roll the '01 v6 bird up on ramps to check...but have other questions as well. tia.

Does the stock cat 'bolt' to the y pipe? from there it is welded to the intermediate pipe I believe.?

I drove over a rock or something and the cat got banged up...yea, that's the ticket. So I want to replace it myself but have no welder. (nor welding experience)
I figure I might as well replace the entire system including the cat with 3" hi-flow cat, 3" mandrel bent tubing and 3" inlet performance muffler. I know many catbacks are 'do it yourself...no welding...' but isn't there a weld somewhere on the cat..either to the "I" pipe or to the "Y" pipe?
Anybody care to share: steps/procedure/components for a complet 3" hi-flow cat to 3" intermediate pipe to 3" inlet muffler? You know...any extra couplings or spacers or reducers or 02 sensor replacement etc...
I plan on not going thrue the drama and intrigue of replacing the stock tubular manifolds...so don't worry about headers for this ride. (good job to those who are more hardcore and dedicated than I...but I think the gains of a 3" full system will be good enough for me [img]graemlins/bowdown.gif[/img] )

I live in an OBDII emissions state. My firebird is my daily driver.

I also figure that once the new system is installed I can have a muffler shop weld the components and loose any leaky brackets?

p.s. I have tried reasearching this on this board and others...just hoping for something a little specific to a Full 3" system...all at once...with stock manifolds.
Thanks gang. [img]tongue.gif[/img]

oh, yea...as far as "needing 3" vs 2.5" vs. backpressure..."real engine mods to come...haven't decided yet between valvetrain/cam or SC kit...still hoping to see a turbo kit available by this time next year...so i plan on using all 3" of performance exhaust, regardless. [img]graemlins/rock.gif[/img]

[ellik]

Among other things, I chose the 3" magnaflow setup for an LT1 because it comes with the mandrel bent 3" S-pipe. the outlet of the Y for my pacesetters was 3". I bought a 3" high flow cat. viola! perfect. all I had to do was cut the flare off the end of the magnaflow S-pipe (set up to bolt to a flanged cat) and band clamped that to my new cat, and band clamped the cat to the Y-pipe. You will need to get an O2 bung welded to the S-pipe, or get an O2 sim for the post cat O2 sensor.

[edit] my stock cat was welded onto the stock Y-pipe, but bolted to the stock S-pipe if I remember correctly.

[grayman]

Oh yea,
The car only has 7k miles on it. 2001. Already talked to muffler shop...they can't touch the cat untill 8 years or 80,000 miles, so i do have to be able to do this myself.
I just found a sorta aplicable post concerning Cats shipping with the y pipe. does this mean I can order a 2 piece system...cat and y pipe...already welded..??..and cut the stock Intermediate pipe off, then remove bolts from y-pipe to manifolds on stock cat...then bolt the new y pipe/cat in its place...then continue on with aftermarket 3" catback system? ( I may have already answered my questios...but many of these posts get mixed up between people with 3.4L or '97 3.8L vs. '01, etc... )

[BLLDOGG]

no, the cat is welded both ends

[grayman]

Thanks ellik,
I think you may have pretty much cleared things up for me.
About the post cat o2 sensor though...I am assuming that shouldn't be a problem for me to take the new magnaflow intermediate pipe (thanks for clearing up the LT1 magnaflow research I was doing by the way) into local muffler shop for welding in the o2 sensor bung. But, do you live in an emissions testing state? if so were you able to pass without a sim? if that's not asking too much. I would rather the system use a stock o2 sensor...less to buy...assuming I can use my current o2 sensor in new intermediate pipe???
I realize you have headers...so this is not a completely equal comparison. Just thought I would ask first before uncorking the "ok, i gotta modifiy what and then sim what and then modify something else bottle."
tia

[Antman]

Yep, as BLLDOGG says, it's welded both ends. I had to cut the pipe in front of the cat (just behind the O2 sensor) in order to fit my new Y pipe for my Pacesetters.

Next mod i'm looking for is a High Flow Cat.
Thinking of retaining the stock I Pipe, as it looks big enough to not cause flow restrictions.

[ellik]

Yes, I live in an emmissions state. Ive been fighting my SES light for months. I ended up replacing all of the O2 sensors. My car is a 97 and between age and being rattled around with the header swap and 2 exhaust changes they were just whipped.

I think I could have passed without the sim, but couldt tell you for sure. When I put the high flow cat on I put in the sim at the same time. Is there any reason why you dont want a sim? In any case, any exhaust shop should be able to burn a hole and weld in an O2 bung in the S-pipe for you. I wouldnt pay more than $10-15 though, so dont let them come up with some rediculous price.

Different people have different results with high-flow cats. Some get lights, some dont. From what I have noticed, it seems like Catco are the worst and Carsound/Magnaflow have the least problems. Just as a nice coincidence, there is a seller on Ebay that has great prices on Magnaflow cat backs and usually include either the cat, or free shipping (or both) in the auction.

[Antman]

I don't want to go for a complete Catback, as I've already replaced the Muffler and tails with Brand new items.
It's only the Cat and I-pipe that are stock now

[grayman]

Concerning sims:
I just don't want to spend the money if not needed. Besides, I have been reading about all these 'sims' issues on this board.
I guess I still don't understand how a 'direct replacement' catback system...say the 2.5 inch magnaflow '98-02, can be a 'bolt up' (no welding required) when the stock cat is welded to the I pipe and also the Y pipe. If the stock I pipe needs to be cut off....what does a 'direct fit' catback system bolt/clamp to. I have yet to find instructions on web from ANY manufacturer of 'direct fit' catback systems. (ellik...i realize you described in earlier post the 3" magnaflow system as the V-8 version...i understand that...) It just seems like the whole catback system industry leaves a lot to be desired as for trying to figure out what fits what and also what modifications realy need to be performed even if not replacing the stock cat. hmmm.

With all that above....I still don't know what the stock diameters are for a 2001 v6 firebird exhaust system. Different literature say different things concerning the different parts...y pipe, cat in-out, i pipe. Example: some say I pipe is 2.25 some say 2.5. arghh.

Also, places that sell...say...a 2.5 inch hi-flow cat don't have a y pipe listed...don't I need a new y pipe after taking the system apart and cuting off the old Cat? And from there...what cat will work with a premanufactured Cat back. again....argghhh.

Is it just a 'parts availability issue' because they didn't make very many of these v6 fbody cars?

I just want it to go fast. [img]smile.gif[/img]

[ellik]

Originally posted by grayman:
I guess I still don't understand how a 'direct replacement' catback system...say the 2.5 inch magnaflow '98-02, can be a 'bolt up' (no welding required) when the stock cat is welded to the I pipe and also the Y pipe. If the stock I pipe needs to be cut off....what does a 'direct fit' catback system bolt/clamp to. I have yet to find instructions on web from ANY manufacturer of 'direct fit' catback systems. (ellik...i realize you described in earlier post the 3" magnaflow system as the V-8 version...i understand that...) It just seems like the whole catback system industry leaves a lot to be desired as for trying to figure out what fits what and also what modifications realy need to be performed even if not replacing the stock cat. hmmm.

With all that above....I still don't know what the stock diameters are for a 2001 v6 firebird exhaust system. Different literature say different things concerning the different parts...y pipe, cat in-out, i pipe. Example: some say I pipe is 2.25 some say 2.5. arghh.

Also, places that sell...say...a 2.5 inch hi-flow cat don't have a y pipe listed...don't I need a new y pipe after taking the system apart and cuting off the old Cat? And from there...what cat will work with a premanufactured Cat back. again....argghhh.

Most of this fitmint stuff is incredibly simple for a shop with a lift, torch supply of reducers and a welder. To just clamp it all together in your driveway with nothing but a wrench and jackstands is another matter.

They made a bunch of v6 f-bodies. most of them are still stock. at least compared to the number of modified v8's

Nobody sells an aftermarket Y-pipe. You'll only get an aftermarket one if you go to headers too. Otherwise, its a stock part. You wont need a new one anyway. The Y-pipe from each of the manifolds are 2.25" off each bank. The combine, or 'Y' into a 3" outlet. Your stock cat is a 3" inlet 2.25" outlet.

V6 catbacks are typically 2.5" that means you need a reducer that goes from 2.25" to 2.5" to make them work.

You said you want to go 3". What you will need to do is take a Saw-Zall and cut the stock cat off cleanly in front of the stock cat. There it will be 3". Put on your 3" in, 3" out high flow cat. Bolt up your 3" cat back. The Magnaflow LT1 setup has the exact same routing as the v-6's and comes with a 3" S-pipe that will bolt right up to the new cat. All you will need to do is cut off about 1/2" of the S-pipe as it is flared for a flanged connection. I do not believe any other setup comes with an S-pipe. Thats where you have to get the SLP install kit, or whatever it is they call it.

[grayman]

Thanks once again ellik. It is all making sense now. I already have a sawsall. :)
I found the $10 sensor bungs too.
The magnaflow full 3" catback is rather affordable as well considering it has the "S" section already in the I pipe.
Now to search through the message board for preffered 3" cat, jack up the car and get dirty, visit the muffler shop and get the new cat welded to Y pipe and have the sensor bung installed...(I have seen some universal cats listed as having a rear sensor bung already..more research...I think magnflow may have been one of those...) Then back under the car. Thanks man, I wish V6 parts sellers were as helpful as you guys. [img]graemlins/bowdown.gif[/img]

[grayman]

Oh, yea...Thanks also to blldogg and antman. All this help is awesome. You all just saved me so much time. (most of the search hits come up regarding headers. I plan on keeping it a bit more simple with the stock tubular manifolds. I would rather put that money (and time) towards something else...like the 1.9 rockers...which I ordered today. :D )

[ellik]

Congrats. You will most likely see a much better gain on the rockers than going from tubular manifolds to headers. Us pre-98 cars with the logs need the upgrade though.

[grayman]

Yea, I kinda figured that. The 'tubes' realy do look like cast headers. I noticed the manifolds when I bought the car a couple of months ago. I thought..."cool...car manufactures are actualy trying to make good exhaust manifolds now..."
The rockers are pricey...until I figure in that I am just not interested in cracking open this engine with 7000 miles on it. And if you do all the things you should do with a cam swap...like double roller, springs, retainers, pushrods, etc...a cam swap starts to add up.
OOPS...wrong forum for valvetrain discussion... [img]graemlins/twak.gif[/img]