adidosc

hey guys, just spent a while searching the forums and after a while i felt like i was running around in circles reading things that weren't really relavant to my situation.

anyway, i have a few questions about the exhaust setup i want to do. i was thinking of doing a true dual setup. instead of having it comebine, i thought about keeping it 3 and 3 with two 2.5 inch pipes (custom bent) running back. there would be an x-pipe crossover in the middle, then two mufflers on the back (possibly dynomax).

i have a few questions however. if i completely replace the stock setup, will i have problems with the O2 sensor? or is there a way around it possibly? i'd like to completely replace the stock system if possible, but before i do that i want to make sure i'm not going to go getting any check engine lights and then find that my performance is suffering.

one last thing...i realize i won't passs visual inspection or emissions...my thought was just to keep the stock system in storage, then when i need to pass emissions just throw it up on my neighbor's lift and bolt it back up to get it to pass. problem solved.

any thoughts? this isn't a done thing yet, any help with my exhaust would be really helpful.

Edit: sorry mods, it was late last night and i didn't think to put this in the engine/transmission section

VSsc400

iTrader: (1)

as long as you don't remove the cats you should be fine in terms of emissions.

I don't know about visual inspection... where I live there are no visual inspections of exhaust systems.

You can always use the weld on O2 bung (10 bucks or something just about anywhere) on your custom setup for the O2's.

adidosc

an O2 bung? never heard of it. but, if it solves any problems i will have, i'm all for the bung.

VSsc400

iTrader: (1)

o2 bung is a a little piece of threaded ring that you can weld on your new exhaust pipe to screw the O2 sensor in. Did you check out my exhaust system? I have the thread in the SC400/300 section under engine transmission under Exhaust sytem finally done...

adidosc

yea i did check that out....really impressed with what you did. where did you install the O2 sensor?

VSsc400

iTrader: (1)

there are 2 O2 sensors on each side. One of them on the headder and the other one on the pipe after the cat.

Looking at some other photos of the australian setup I measured out how much room I would need to install the australian headders and 2 10" cats. This measurements came to just about 14" beyond the stock cats. The post cat O2 is located 5-6" after the cat so i was able to leave it in the oringial position.

adidosc

seems as though you and i are the only two reading this thread here VS...

anyway, you mentioned two 10'' cats...however on your setup you have no cats, correct? my setup will be similar to the one you showed in the pictures, only i'm a 300 vs your 400. also, no cats...so how do i position the O2 sensors so it thinks its working the same as with cats?

VSsc400

iTrader: (1)

seems as though you and i are the only two reading this thread here VS...
quite possibly =)

anyway, you mentioned two 10'' cats...however on your setup you have no cats, correct?
incorrect. I kept the 2 stock cats. even when I get the australian headders I will have cats.

my setup will be similar to the one you showed in the pictures, only i'm a 300 vs your 400.
from what I understand the exhaust setup is largely similar. at least from the midcat/resornator back.

also, no cats...so how do i position the O2 sensors so it thinks its working the same as with cats
for the no-cats setup you can buy O2 simulators or you can weld on O2 bung and install the O2's. should make no difference cat or no cat... but I think you should plug in all 4 O2 sensors.

with all the stuff I'm doing I'm trying to keep them emission legal.... our evironment is counting on us.

adidosc

so you think i'm better off just replacing my setup from the cat back to not mess with the O2 sensors? i don't necessarily have to go with a catless setup...i just want something that will relieve the engine and let it work better while also improving the way it sounds as well...sorry for asking all the questions, just want to make sure i have everything straight before i go ripping and tearing.

VSsc400

iTrader: (1)

supposedly on the SC4(not sure about the SC3 but they are probably same) the cats are pretty efficient. I would leave the cats on and not bother with all the O2 stuff.....
I can feel the exhaust having no restriction with the catback setup.

also another thing.... I put a slip joint all the way at the front of my exhaust system so when its time for headders I can just unclamp and remove instead of having to cut again.

adidosc

so if i just go with a cat back exhaust, will i sitll pass emissions? it'd be nice if i didn't have to worry about that come time to test as opposed to doing the full exhaust setup....

do you think after 144k miles the cat would be clogged at all? i don't know too much about the stock cats myself to know whether it'd be worth replacing them or not. if it is, a high flow is always a possibility.

VSsc400

iTrader: (1)

my cats are 11 years old and they were fine.
I don't see why you wouldn't pass inspection if you go with catback.
in my state there are no checks for aftermarket exhaust systems and since my setup is not loud and I still have my cats so i would pass.... your state may have sound level limit or something....

adidosc

well sounds like cat back would be my best bet

VSsc400

iTrader: (1)

if you need any assistance let me know.... I've driven over 1000 miles since the exhaust was done and its working great...

adidosc

i will keep you posted with what i end up doing...but right now doing cat-back and not having to mess with any O2 sensors sounds pretty good...

do you happen to know of a good deal on mufflers by chance? i have somebody checking on prices of dynamax ultra flo's, those seem to be pretty popular on exhaust setups...