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Old 01-27-2011, 11:22 PM   #1
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Default How much pipe to order for DIY catback?

Just wondering what anyone with a custom exhaust used in terms of pipe. I'm planning on ordering the stuff for mine soon so I need some rough numbers.

Plan is a 3" catback, no cat (Exhaust will have to be extended to the DP exit), small muffler. Exit at stock location.

Thoughts?

BTW: Are these crap or acceptable?
http://cgi.ebay.com/ebaymotors/2-3-E...Q5fAccessories
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Old 01-27-2011, 11:31 PM   #2
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what are you doing for mufflers/resonators?

from the end of the DP to the tip is about 12-14 feet depending on bends used and routing minus mufflers and cat.
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Old 01-27-2011, 11:34 PM   #3
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Originally Posted by shlammed View Post
what are you doing for mufflers/resonators?

from the end of the DP to the tip is about 12-14 feet depending on bends used and routing minus mufflers and cat.
Thanks.

Haven't decided on the mufflers/resonators. It'll either be a long resonator or a small muffler. I'll probably end up with the small muffler since I don't want to be getting pulled over all the time.

What angle should I have the bends to and from the muffler be at? Should they be 60* or can I get away with 45? I know it depends on the muffler, but just as a rough estimate, what did you guys do in terms of angles?
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Old 01-28-2011, 12:38 AM   #4
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Don't bother ordering the ebay flanges if you can get them cheaper at your local exhaust shop. I know i can get mine cheap because my uncle owns a exhaust shop, but they cant be that much regardless.
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Old 01-28-2011, 12:53 AM   #5
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depends on your muffler however if you like to be acceptable to society, you want to get a 18"+ muffler which would require you to do a 180 bend and then another 90 bend back and also a 90 bend for the exhaust tip in other words you want to get 2 180` bends and then pipe from the rear diff to the cat. Over the summer i'm planning on getting a 90` stainless steel bend and using that as an exhaust tip instead of using an actual tip.
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Old 01-28-2011, 01:30 AM   #6
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Ordered this:
http://www.amazon.com/gp/product/B00...ef=oss_product

I will probably weld it into the midpipe and do a strait pipe from there on back. I'm thinking of using a 60 degree at the end of the midpipe, cutting across, and using another 60 degree to get right out the stock location. That way I can modify it to fit a muffler if I think it's too damn loud.

Thoughts?

BTW - resonator is 14" long.
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Old 01-28-2011, 03:37 AM   #7
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Just used some long straigh 2.5" piping off downpipe all the way to the back with a flowtech warlock muffler on it right out the middle of the car.

muffler was mostly costly item of it all at 70 dollars
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Old 01-28-2011, 08:29 AM   #8
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Originally Posted by Techsalvager View Post
Just used some long straigh 2.5" piping off downpipe all the way to the back with a flowtech warlock muffler on it right out the middle of the car.

muffler was mostly costly item of it all at 70 dollars
Any idea of the specs on the muffler and angles used?
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Old 01-28-2011, 05:15 PM   #9
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Quote:
Originally Posted by rider384 View Post
Ordered this:
http://www.amazon.com/gp/product/B00...ef=oss_product

I will probably weld it into the midpipe and do a strait pipe from there on back. I'm thinking of using a 60 degree at the end of the midpipe, cutting across, and using another 60 degree to get right out the stock location. That way I can modify it to fit a muffler if I think it's too damn loud.

Thoughts?

BTW - resonator is 14" long.
6 x 20 x 6 inches.... u get a 6" muffler between the driveshaft and the wall, a lot of people will bow to you...
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Old 01-28-2011, 05:20 PM   #10
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52 feet for a tuned exhaust! think "french horn"
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Old 01-28-2011, 05:28 PM   #11
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52 feet for a tuned exhaust! think "french horn"
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Old 01-30-2011, 03:47 PM   #12
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if you can't do it with one 180* bend and 10' or less of pipe you are trying way to hard. that magnaflow will not likely fit in the trans tunnel. with 3'' pipe even the glasspack / cherry bomb style is likely to cause knocking and banging under there on bumpy roads, but can be done if you take your time. here is what I suggest.

1) get a smaller resonator and fit it where your cat was.
2) get one of these http://www.mandrelbendingsolutions.c...-Degree/Detail
3) use the 45* section at the diff. bisect the bend at the center of the angle/rotate 180* and weld back together. this will give you the perfect step around the diff and axle while maintaining the pipe centered in the trans tunnel. will look something like this when done http://www.mandrelbendingsolutions.c...-Offset/Detail
4) from there it depends on the muffler you choose.
5) a little trick I like to use is (when welding on the tip) is to fold a rag over a few times and drape it over the tip/pipe that is going to protrude though the bumper cut out and push it up tight. if you do it right it'll give you a perfect gap all the way around the tip.
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