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WOT Junkie and avid corn burner
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Discussion Starter #1
What size is the piping from the two main cats leading to the third? I'm thinking of putting an X pipe in place of the third cat and running individual pipes to the stock mufflers. Any minor power gains from this? The size piping I want to run is 2.25".
 

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stock size is 2" if you want to run 2 1/4" it wont hurt anything
 

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WOT Junkie and avid corn burner
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Discussion Starter #3
I suppose adapters are available for this. Or maybe I should wait until I replace my cats. 88,000 miles on the odometer now. At least this way, I'll have 2.25" all the way.
 

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I'm not running adapters, just slide the pipe over it and weld. I'm running 2 1/4" duals on my bird.

 

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WOT Junkie and avid corn burner
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Discussion Starter #5
My dad said 2.25" is all I need if I plan on running duals unless I go supercharged, which I don't plan on doing in the next ten years or so. Now if only I can convince him to let me have the exhaust done. My car, but his on paper.
 

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Your dad is right. Many others on here will agree, for a mild built 281 2.25 is ideal, after that your adding noise. There was a chart for engine displacement/horse power and recommended pipe size, I don't know what happened to it though.
 

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The stock pipes after the first cats are just under 2". If your going to do exhaust work i think 2.25" is good. Another thought of mine is that the front cats are really bad, if your going to redo your exhaust i would redo it all the way from the manifolds. If you still have 2" pipe after the cat that goes into 2.25" pipe your still restricted, see what i mean?

The chart chris is taking about is still in the tech articels under the exhaust page last time i checked.

hope this hopes.
 

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WOT Junkie and avid corn burner
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Discussion Starter #8
Yeah, my dad is allowing me to replace the cats and agrees with me on high flows. I'll wait until 90K comes around which is 2K away. Then I'll have an X pipe put in place of the third cat and run the pipes to the stock mufflers. Fortunately, there is no required emissions testing here in Southeastern VA. Oh yeah, when should I have my O2's replaced?
 

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Your dad is right. Many others on here will agree, for a mild built 281 2.25 is ideal, after that your adding noise.
x2, as well more than 2.25 with our small displacement engines and you can lose low end torque. We don't have low end torque to spare either..:D
 

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WOT Junkie and avid corn burner
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Discussion Starter #12
I would put headers on it, but I just can't justify the cost right now. I was thinking of replacing the O2's but my dad always tells me "Don't fix what ain't broken!". I just figured that they might be losing their accuracy by now. Well thanks guys. Probably sometime in the near future, I'll put an X pipe on the car and have true duals! What is the average power gains from such exhaust modifications?
 

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WOT Junkie and avid corn burner
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Discussion Starter #14
what do you mean by not much? How about torque?
 

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I have no idea about the exact numbers, but iv seen what alot of other guys say and have told me about our exhuast and that the HP gain wont be much. Maybe 10 if your lucky. Exhuast is nice and does help but there is other problems with our cars, non PI heads, tune, stock intake manifold, etc. Not trying to discourage you by any means, i put about 800$ into my exhaust, just dont expect alot.

With an increase of .25" i dont think your torque will change.
 

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When I did my exhaust in November. I used 2.25" pipe from front to back with new hi flow cats. My cats were plugged up pretty badly and smelled when you drove the car. When the new exhaust was done it was like a new car. I wouldn't guess on what the HP increase was, but I'm sure I had lost some performance with the bad cats. In the end the car runs and drives better. It seems to move quicker so it was worth it.
 
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