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Flex Pipe Question

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Old 07-09-2013, 09:46 PM
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Default Flex Pipe Question

So now that my starter is fixed and everything seems to be running smoothly I am going to get rid of my rattling cat. Question is I don't want a cat anymore and was wondering if anyone knows anything about Flex pipes?
http://www.autozone.com/autozone/acc...ier=255970_0_0_

This is what I am thinking in place of the cat. It is stainless and straight through...which should be great for when I slap my new muffler on for sound.
Any thoughts on this?
 
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Old 07-09-2013, 10:58 PM
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Will taking out the cat have any affect on the O2 sensors?
 
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Old 07-09-2013, 11:00 PM
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in the OLD days we would take the cat out. then use a heavy metal rod and punch the guts out of it. then put it back in. and it looks like it is fine.. BUT it might have a rattle of funny sound. that was a long time ago. i would not use flex tubing for exhaust. good luck.
 
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Old 07-09-2013, 11:35 PM
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Originally Posted by RollerRed
So now that my starter is fixed and everything seems to be running smoothly I am going to get rid of my rattling cat. Question is I don't want a cat anymore and was wondering if anyone knows anything about Flex pipes?
http://www.autozone.com/autozone/acc...ier=255970_0_0_

This is what I am thinking in place of the cat. It is stainless and straight through...which should be great for when I slap my new muffler on for sound.
Any thoughts on this?
Yeah, but not in polite company. Don't you have smog testing in Pierce County? Ya think you'll pass without a cat?
 
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Old 07-09-2013, 11:36 PM
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I've read a lot of people do exhaust work and just tie the 2nd O2 up onto the frame and never get any CEL's because of it. I will be leaving both of them right where they are, Just going to cut right at both ends of the Cat.
A lot of cars that I have worked on have flex pipes just like the one I'm interested in to cut back on exhaust rattle. I am really feeling this for simplicity sake...

Also where I live there is no testing, so I am golden!
 
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Old 07-10-2013, 01:08 PM
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You can put a non-fowler on the o2 sensor and it wont throw a code(just moves the sensor out of the pipe so it reads a lower temp) but flex pipe is a bad idea. Not sure where youre located but in PA its only legal on a diesel.
 
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Old 07-10-2013, 03:20 PM
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Well its either a flex pipe or just a straight pipe where the cat used to be...
Why is everyone so against the flex pipe though? Straight pipe is similar to a flex pipe, plus for people that have hollowed out their cats you would have noticed a difference in performance and noise I am sure?
Now I'm not looking for a real performance boost, just ease of instalation and to keep cost down. $25-$30 for me to install a flex pipe vs $150 to have someone weld up a new cat...Doesn't that seem intelligent for those that don't need to do emissions?
 
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Old 07-10-2013, 05:50 PM
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Back in the '70's, I had a custom van that I put side exhaust on. To connect the headers to the side pipes, they used flex pipe. It burned through within 6 months. I replaced the flex with solid pipe and didn't have any more problems. It might be cheaper at first, but then add in the expense to redo it again in a few months.
Z1_zps4f34c368.jpg
 
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Old 07-10-2013, 06:34 PM
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Its cheaper to get a piece of straight pipe... Use that and be done with it.
 
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Old 07-10-2013, 07:32 PM
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Fine Fine. Straight pipe it is! Just thought I would be different...
So just to clarify you have to pull the rear O2 and put a cap on it when you zip it to the frame? You cant leave it it attached when you cut the cat?

Also on a side note...bad a** van! Wish I had one like that!
 

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