3" exhuast.
12-06-2006, 02:07 PM
#1
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3" exhuast.
does anyone make dual 3" exhuast. i was lookin at mac LT headers. and im guessing the collector size is three inch. so i thought three inch the rest of the way would be better than 2.5 thanks for ne help
12-06-2006, 06:53 PM
#2
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Join Date: Oct 2005
Location: Frederick, Md
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RE: 3" exhuast.
STAINLESS WORKS has 3" back exhaust systems for there headers and xpipes. should work with mac LT headers and some modification but i wouldnt expect much gain. i got my SW 1.75" headers with high flow cats and x pipe for $700 shipped. now after 300 dollars in ceramic coatings i'll be ready to install them. to get the same kit from a retailer would have cost $2000 at least. they are beautiful pieces though. come spring time ill run my car at the track with the full exhaust then dump it behind the x pipe see if i'm really losing any power keeping the 2.5 inch exhaust on it or do i need to get the 3 inch... the kit is $881 with mufflers but you can probably call them and get just the mid pipes for like $450 since you probably have mufflers of choice.
12-06-2006, 10:01 PM
#5
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RE: 3" exhuast.
GMS has an entire 3" exhaust for the S197. I even belive they have headers for them. Why are you stepping up the exhaust diameter? Is it for a high hp app? I would think you would lose a bit of back pressure on a stock(or lightly modded) GT.
12-06-2006, 10:05 PM
#6
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RE: 3" exhuast.
Loosing backpressure is always a good thing, so long as you don't upset the resonance tuning of the exhaust.
However, I'd bet that you'd get a better improvement by switching to some really killer merge collectors with a megaphone-reverse cone setup (check out Burns Stainless).
Throwing bigger tuning on there isn't always an improvement.
However, I'd bet that you'd get a better improvement by switching to some really killer merge collectors with a megaphone-reverse cone setup (check out Burns Stainless).
Throwing bigger tuning on there isn't always an improvement.
12-06-2006, 10:13 PM
#7
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RE: 3" exhuast.
ORIGINAL: CrazyAl
Loosing backpressure is always a good thing, so long as you don't upset the resonance tuning of the exhaust.
However, I'd bet that you'd get a better improvement by switching to some really killer merge collectors with a megaphone-reverse cone setup (check out Burns Stainless).
Throwing bigger tuning on there isn't always an improvement.
Loosing backpressure is always a good thing, so long as you don't upset the resonance tuning of the exhaust.
However, I'd bet that you'd get a better improvement by switching to some really killer merge collectors with a megaphone-reverse cone setup (check out Burns Stainless).
Throwing bigger tuning on there isn't always an improvement.
But yeah I guess losing backpressure isn't a bad thing as long as you have some low back pressure right?
12-07-2006, 12:38 AM
#9
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RE: 3" exhuast.
ORIGINAL: Timmay!!!
Actually I know what the merge collectors are, I was just too impatient to think about what you were saying[8D]but what is a reverse mega-phone cone setup?
Actually I know what the merge collectors are, I was just too impatient to think about what you were saying[8D]but what is a reverse mega-phone cone setup?
First you have your primaries that come from each port. These all join at your collector. Then you have the "megaphone". This is a length of pipe that attaches to the collector and gradually widens (think like one of those "cones" that cheerleaders yell through). Then you have the "reverse cone", which is a short section of tubing that suddenly narrows down from the wide opening of the megaphone back to your tailpipe size. The length, angle, and diameter of the megaphone and reverse cone are adjusted to help broaden the peak powerband of the engine.
When I said "really killer merge collector" I simply meant that the collector (where the primaries come together) was extremely well made.
You can read about this stuff here: http://www.burnsstainless.com/MergeC...ollectors.html
You can also see pictures of exhaust parts that will make any gearhead drool.
...mind you, this is serious race type exhaust. It's expensive, and is all about squeezing every last drop of HP out of the engine.
Regarding backpressure. Backpressure is ALWAYS bad. Period.
Now, I know you're thinking "Wait a minute Al, I've heard people say that motors need some backpressure to run properly". You might even have experienced it. For example, people sometimes see a power LOSS after removing their tailpipe.
Now, here's the kicker: This MYTH comes about because people think "oh, when I removed my tailpipe and my HP dropped, that's becasue I now have too little backpressure". That is an incorrect conclusion. The HP drop did not come from backpressure loss. It came becasue the resonant properties of the exhaust pipe changed. When you alter the shape, diameter, and length of an exhaust pipe you are changing two things: backpressure (resistance to flow) and the resonant characteristics of the pipe. They are two seperate things.
Backpressure is ALWAYS bad.
Resonance can be bad or it can be good, it depends on many circumstances and what your goals are. (This is why thin, long, headers are best for low-end HP whereas short, wide, headers are good for top-end HP).
12-07-2006, 01:22 AM
#10
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RE: 3" exhuast.
Well lets say I straight pipe the stang, how do I keep good resonance? I guess it depends on what kind of power goals you are looking for like you said earlier right. Maybe there is no real good or bad, just tradeoffs and compromises.