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Old Apr 9, 2008 | 12:19 AM
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Default Cool exhaust idea

I just measured today where my magnaflow 3" cat back clamps over the factory y and the outlet from the factory y pipe where it merges is 2 5/8" so my thinking is to cut off that part where it necks down to 2 5/8" and cut it back till where it is 3" and then weld a replacement 3" pipe straight to the 3" magnaflow cat back. Should i see a worth while gain? i know it wont cost much or take much time. Or does anyone have any pictures of someone else doing this? Thanks
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Old Apr 9, 2008 | 01:45 AM
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no. it wont be worth your money, even if its free.
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Old Apr 9, 2008 | 02:09 AM
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Do you have plans on replacing the y-pipe to a 3-inch. Id say do it but only if you get a new Y.
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Old Apr 9, 2008 | 03:24 AM
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I would stick with what you got. You may end up being pissed at yourself for messing up your current setup.
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Old Apr 9, 2008 | 06:48 AM
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Originally Posted by 180ls1
I just measured today where my magnaflow 3" cat back clamps over the factory y and the outlet from the factory y pipe where it merges is 2 5/8" so my thinking is to cut off that part where it necks down to 2 5/8" and cut it back till where it is 3" and then weld a replacement 3" pipe straight to the 3" magnaflow cat back. Should i see a worth while gain? i know it wont cost much or take much time. Or does anyone have any pictures of someone else doing this? Thanks
Just Do it! I have done it to several systems. Any improvement in flow is an improvement in flow.
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Old Apr 9, 2008 | 08:44 AM
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Originally Posted by orangeapeel
I would stick with what you got. You may end up being pissed at yourself for messing up your current setup.
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Old Apr 9, 2008 | 08:58 AM
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Originally Posted by orangeapeel
I would stick with what you got. You may end up being pissed at yourself for messing up your current setup.
x3 on this one.
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Old Apr 9, 2008 | 11:07 AM
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I just saw this. So i knew i am losing power i just dont know how much, so i would imagine 2 5/8 is good for no more then 275 or so without loss

quoting JRP:

A 2.75” (stock) single system is good for a 310hp engine with zero loss…
A 3” Single system is good for a 370hp engine with zero loss…
A 3.5” Single system is good for a 503hp engine with zero loss…
A 4” Single system is good for a 657hp engine with zero loss…
A 2.25” dual system is good for a 457hp engine with zero loss…
A 2.5” dual system is good for a 513hp engine with zero loss…
A 3” dual system is good for a 812hp engine with zero loss…
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Old Apr 9, 2008 | 11:17 AM
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I'd say just do it! I had it like that from day one when I put my flowmaster together. My cousin gave me his old Y pipe I think it was SLP or somthing and then bought a flowmaster muffler and made my own cat back. It sounded great! Heres a pic of the Y pipe.
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Old Apr 9, 2008 | 11:39 AM
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a single 3" is only good to 370 ouch...
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Old Apr 9, 2008 | 11:45 AM
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Originally Posted by 180ls1
I just saw this. So i knew i am losing power i just dont know how much, so i would imagine 2 5/8 is good for no more then 275 or so without loss

quoting JRP:

A 2.75” (stock) single system is good for a 310hp engine with zero loss…
A 3” Single system is good for a 370hp engine with zero loss…
A 3.5” Single system is good for a 503hp engine with zero loss…
A 4” Single system is good for a 657hp engine with zero loss…
A 2.25” dual system is good for a 457hp engine with zero loss…
A 2.5” dual system is good for a 513hp engine with zero loss…
A 3” dual system is good for a 812hp engine with zero loss…
not worth it still, the round 2 5/8 pipe flows better than the drivers side flat pipe..... if you want to do anything to the stock pipe, replace the flat part. otherwise just wait it out untill you get headers and get a full 3 inch Y-pipe. id say your losing all of about .5 HP with the smaller pipe in the I, but your losing .75 in the flat part of the drivers pipe.

i mean, if you want to do it still, more power to you. but your pissing into the wind. i garuntee, you will notice nothing, and even if you dyno it, you will see nothing because the variances in conditions and dyno's will outweigh the results.
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Old Apr 9, 2008 | 11:46 AM
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Originally Posted by LS1crazy01
I'd say just do it! I had it like that from day one when I put my flowmaster together. My cousin gave me his old Y pipe I think it was SLP or somthing and then bought a flowmaster muffler and made my own cat back. It sounded great! Heres a pic of the Y pipe.
hell ya that is what i was looking for. Thanks, and after seeing that chart i think it would definately be in my best interest to do that mod.
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Old Apr 9, 2008 | 11:47 AM
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Do it . Do it
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Old Apr 9, 2008 | 12:14 PM
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Why not just pay $40 bucks for a Flowmaster Y merge to replace the stocker with?
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Old Apr 9, 2008 | 12:31 PM
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Originally Posted by JEB99TA
Why not just pay $40 bucks for a Flowmaster Y merge to replace the stocker with?
would i see worth while/money gains from that vs a $5 piece of pipe? I was thinking about it but i will look into it more.
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Old Apr 9, 2008 | 12:35 PM
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your not going to see jack **** from any of it, so why bother?
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Old Apr 9, 2008 | 12:43 PM
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better idea...

pacesetter longtubes
custom 3"ory into a flowmaster merge
and a cutout
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Old Apr 9, 2008 | 12:48 PM
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not worth the effort
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Old Apr 9, 2008 | 01:03 PM
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Originally Posted by 5_02ls1
better idea...

pacesetter longtubes
custom 3"ory into a flowmaster merge
and a cutout
california

and i have a cutout installed
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Old Apr 9, 2008 | 03:52 PM
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ok....were trying to keep you from hacking up your stock Y thinking your going to gain something.

1. shorties or if your on a budget, get 00+ manifolds
2. 2 high flow cats and put them in the same place as your stock cats
3. SLP Y-pipe, that doesnt have the flat peice on the drivers side
4. if your really worried, get a flowmaster merge and do the mod on the new pipe. but the stock merge is more than sufficient for stock manifolds and a cat back.
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