O2 Sensors
05-05-2007, 01:47 PM
#1
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O2 Sensors
So I took my 2002 3.8 to the exhaust shop yesterday and I saw that it had 4 cats. There were 2 O2 sensors closer to the headers/1st cat and then 2 more near the beginning of the second cats. They guy wanted to cut it just before the second cats and put 2.25" piping to a small X and then more piping to 2 flow pro mufflers. My question is, the O2 sensor on the passenger side just before the second cat is actually in the cat it self so if he cuts it before that the O2 will be thrown off, he said that he will cut a hole in the pipe and put it back in there, will this work and not give me a CEL? I heard one he did a while ago and sounded ok but not very loud at idle. Would an H-pipe give me better sound? I told the guy I wanted 2.5" pipes and he said it would make it sound sick, is he right? Lastly would a 04 GT cated H pipe fit on mine? I think I am going to get the cated H pipe from a GT and run 2 flowmaster 40 or super 40 mufflers? What do you guys think?
05-05-2007, 02:12 PM
#3
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Why cant I have both? How am I not getting performance by going to a true dual system and opening it up for more flow? I would do the headers too but I have to pay for tuition first unless your willing to help out? How is doing a new custom exhaust sytem not giving me performance am I in the dark?
05-05-2007, 05:11 PM
#4
My apologies, It sounded more like you were worried about how the car would sound then how it would perform. I went 13.2@102.2 with stock headers and an open stock 4 cat h-pipe (of course that was with a 5.0, but the logic still applies). Until you really start breathing in more air don't worry about the exhaust too much. You'll spend a lot of money, getting a car that sounds like it'll run 11s and then ends up being SLOWER than stock because you've killed all yor tq by getting rid of the back pressure. Just put some magnaflows on with your stock exhaust and be done with it for a while. Put that other money into performance goodies.
05-05-2007, 06:14 PM
#5
If the 02 sensor is before the rear cats, you can remove them if you want, you may end up with problems come e-test time though, I'd just leave them on, you won't notice the power/sound difference.
As for sound, an H will sound much nicer, it will give you a deeper tone, more like a V8, the X will be higher pitched and sound raspy, not a fan personally, Flowmasters will likely give you a decent sound, but Imco sounds better and louder from what I've heard.
A 2.5" dual system on a V6 will likely kill some power and will surely kill your torque-especially low-end torque, a 2.25 system is more than enough for a 3.8L.
As for sound, an H will sound much nicer, it will give you a deeper tone, more like a V8, the X will be higher pitched and sound raspy, not a fan personally, Flowmasters will likely give you a decent sound, but Imco sounds better and louder from what I've heard.
A 2.5" dual system on a V6 will likely kill some power and will surely kill your torque-especially low-end torque, a 2.25 system is more than enough for a 3.8L.
05-05-2007, 08:59 PM
#6
What they said.
i just looked at a set of cats today, and i think i know what you are talking about.
The 02 bung is in the cat, but it is before the "stuff" in the cat.
So if your guy put a new bung in the pipe for the 02 senor you will be good.
i just looked at a set of cats today, and i think i know what you are talking about.
The 02 bung is in the cat, but it is before the "stuff" in the cat.
So if your guy put a new bung in the pipe for the 02 senor you will be good.
05-06-2007, 01:33 AM
#7
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Yeah I think thats what he wanted to do. The O2 sensor on the passenger side is located more downstream that the driver side. He wanted to cut right before the rear cats and put in the pipes from there on (leaving the precats in). But yeah something about a bung and then putting it back in didnt trigger the CEL on a couple other ones he has done. So I think I am gonna do it and get the H pipe instead of the mini X he had done before. Does anyone know where I can get flowmaster super 40s or delta 40s for cheap?
05-06-2007, 04:53 PM
#9
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yeah you have a point but opening it up too much would make it sound sick and i would be farting around town. The flowmasters add "control" to the noise and turn it into something worth listening too... Scores what do you recommend is a good setup for my car in terms of exhaust? If you would powder coat me some headers for free then I would think you were on to something and the other 1000's of guys with flowmasters would be wrong.
05-07-2007, 01:56 AM
#10
a good set up for a stockish 3.8 would be to port the stock headers (smething you can do at home for free lol), leave the stock cats, get a set of magnaflows and have a mandrel bent 2 and a 1/4 inch cat back done. It'll sound good, work good, and will be way easier on the wallet leaving money for other go fast goodies.
I'm not saying all the people running flows are making a mistake, back pressure is back pressure whether you get it from the cats or the mufflers. If I wanted to run an off road h-pipe and after market headers I'd run a set of 3-chamber flows too just to keep the back pressure up. It's 6 of one thing and half dozen of another. In my case it was simply easier and cheaper to keep the stock stuff and spend my money on bigger bangs like gears.
I'm not saying all the people running flows are making a mistake, back pressure is back pressure whether you get it from the cats or the mufflers. If I wanted to run an off road h-pipe and after market headers I'd run a set of 3-chamber flows too just to keep the back pressure up. It's 6 of one thing and half dozen of another. In my case it was simply easier and cheaper to keep the stock stuff and spend my money on bigger bangs like gears.
