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Going from catback with cutout to TD's

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Old Nov 25, 2006 | 11:45 PM
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Default Going from catback with cutout to TD's

I am going to replace the Magnaflow catback with true duals with single chamber flowmasters
I am hoping for a little gain on the power and of course the sound will be awsome. but I wont have the option of flipping the switch and making the car quite. heres the questions.

here is the setup I have now
Hooker LT's, Hooker ORY, Magnaflow catback with 12" bullet in the I-pipe and 3" cutout with McCord PP2 opener before the axle
it is loud as hell with the cutout open, will the sound be louder with the TD's?
As in will it sound better, more controled type of sound, and maybe a bit quieter than the open cutout since it will the going through a type of mufflers rather than a open pipe.

And will I really see a much bigger gain(as in HP but I would think that the 2 1/2" pipe would have a little bit more back pressure there fore help produce more torque, does that sound right?) with 3" pipe rather than 2 1/2", because I would really like to go 2 1/2 if its only going to be 2-3hp, for the ground clearence. and will the sound be alot different between the two sizes?

I have to say the a big influence on the choice I have made is jmm98ls1's car. the sound alone makes me think of my dads old nova with the 396ci Big Block. I love it!!

Sorry for all the questions I have done about a dozen searches and cant find the answers I am looking for. so thanks
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Old Nov 26, 2006 | 12:55 AM
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I run true dual 2.5" from the collector to the tip. I picked up tremendous power from this setup over my hooker catback and ORY w/ cut-out in the I-pipe. The butt dyno was a definite. Around 9 rwhp just from switching.

You are not wanting back pressure. You need the effects of scavenging and exhaust gas velocity. You will achieve this with the 2.5 over the 3" setup. Thefore you might have more power with the 2.5". Remember that you have 2 pipes. The bottleneck point will be the X section if there is really one at all. Sounds relatively the same. I have a video that is in my sig on the "true duals" link. It is loud just sitting still. If I drop the hammer on it....good Lord.
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Old Nov 26, 2006 | 11:00 AM
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Ok I get the velocity with the 2 1/2 but I was thinking of going with a H-pipe instead of a X-pipe.
I was told it would be a better fit with the Sphon TA tunnel brace and my SLP DD subfames.
but if I can get a X should I over the H?
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Old Nov 26, 2006 | 04:04 PM
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anyone else?
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Old Nov 26, 2006 | 06:28 PM
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H seems to be a favorite. I am not partial to either one honestly. I like them both.
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Old Nov 26, 2006 | 06:49 PM
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Very cool, I cant wait to get these on
But I have X-mas first I am sure all of you know that if you forgot to get your wife something but took the time and money to get something for your car your *** would be grass!
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Old Nov 26, 2006 | 08:55 PM
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I just put on some 3" duals over the axle. The shop that did them suggested 2.5" but I have plans for a stroker and a big shot later on so I decided on 3". Also last time it was on the dyno I picked up 30rwhp and 30 rwtq by opening up my dual 3" cut outs. So i'm hoping to see similar gains with the duals.
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Old Nov 26, 2006 | 09:32 PM
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I am going to be sticking with stock cubesfor a awhile, but after nothing bigger than 402
but nest year will jsut be a heads and cam with 150shot
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