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Discussion Starter · #1 ·
OK...I've read the "newbie" sections on several sites and still have some questions:
1. What is the most restrictive part of the exhaust? The exhaust manifold, the factory y-pipe and cats or the cat back portion of the exhaust.
2. Are there exhausts that perform well that aren't nasty loud...or is it a pretty direct ratio of loudness to performance.
3. Is it reasonable to hope for 320-340 rwh with lid, lt's, and a catted y or will the stock muffler eat up all the gains.
Thanks,
ws6vert
 

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Depends on the motor in your car. Ls1 you MIGHT see that. Now i love loudness and most of the loud exhausts have the most power gains. A lid doesnt do much for you until you have full exhaust. So 320 might be possible depending on year model and a few other things but id look to breake even at 300 or a little over with a lid and exhaust.
 

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ws6vert said:
OK...I've read the "newbie" sections on several sites and still have some questions:
1. What is the most restrictive part of the exhaust? The exhaust manifold, the factory y-pipe and cats or the cat back portion of the exhaust.
2. Are there exhausts that perform well that aren't nasty loud...or is it a pretty direct ratio of loudness to performance.
3. Is it reasonable to hope for 320-340 rwh with lid, lt's, and a catted y or will the stock muffler eat up all the gains.
Thanks,
ws6vert

1. It's all pretty resrtictive. I'd say the stock Y pipe is the biggest culprit followed by the cats, then manifolds, then cat-back.

2. There are a few out there that will have decent gains yet are relativley quiet. Borla is adjustable but it's not cheap. Random Technology makes a quieter catback and so does the Flowmaster 80 series, but it is more restrictive than the stock catback believe it or not.

3. Out of an LS1 yes your goals are reasonable. If you would like to keep the stock catback and do headers/catted Y, I'd suggest putting in a cut out. Then you can basically uncap 5 hp and make it louder. But when you want to cruise, cap it up and it's quiet.
 

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Discussion Starter · #4 ·
Thanks! It's a 2000 ram air 'vert. I haven't had it to the strip yet...am hoping for high 13's with the 3.23 gears it has. (it's an A4). Looking to get into the mid-low 13's with bolt on's....which should be doable...at least the lighter coupes are doing it pretty easily. :thumbsup:
My initial goals aren't too high...but I guess we all know that can change.
ws6vert
 

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2. The magnaflow is your best bet if you want performance w/o extreme sound. On an otherwise stock car it is very tame, when you get on it, it really wakes up. I have a magnaflow on my LT/off-road y pipe car and it is not obnoxious at all.
 

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IMO the cats are not terribly restricive. Basic exhaust theory says to make the most power deal with the restriction closest to the motor first.

That would actually dictate doing headers and ditching the manifolds FIRST before even touching the rest of the exhaust, but most of us don't do it that way.

On an LS1 I'd say the Y is the most restrictive just because of the crushed section, then the manifolds, then cats, then catback.
 

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I have the Hooker catback, supposed to flow really well and is'nt loud (also one of the cheapest in price). Headers and Y-pipe are next:)
 

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Discussion Starter · #14 ·
Thanks!

I'll probably do either LT's and catted Y or else Mac mid-length and catted Y this winter as well as an electronic bypass for the Y-pipe. Going to check out the factory ram air setup and see what I can do to improve on the air coming in as well. I already have more power than the tires can handle as soon as the temp drops below 70, so may have to look into DR's too.

A small convertor in the A4 would help times if I can get the car to hook.
Cheers....
WS6vert
 
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