Backpressure?
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Joined: Jun 2003
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From: SW VA
Backpressure?
Would I have enough backpressure if I cut the stock muffler off of my 4.6L? The stock cats and everything would still be on there. I just did this to a friends truck, and it sounds awesome!
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From: Edgerton, WI
I think you would lose some low rpm power. When I first bought my '99 F-150, thats now the exhaust was. It was basically dual straight pipes after the cat.
I put a Flowmaster 50 Series on it and it you can feel the gain in lowend power, not the mention the fact that it sounds good, not just loud.
I put a Flowmaster 50 Series on it and it you can feel the gain in lowend power, not the mention the fact that it sounds good, not just loud.
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From: SW VA
Thanks for the reply. My friend's Dodge had a Flowmaster (2.5" SI/DO) on it...not sure of what series it was (Im thinking 50 series), and he said I could have it. I just wanted to run around with no muffler for a while to see what it was like. If I dont like it, I can put his old Flowmaster on...
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From: Prince George, B.C.
It will be just fine without the muffler, the cats are more then enough to keep you from losing low end. Better yet, get rid of the cats, and get a good free flowing muffler, long magnaflow or somthing like that. A 2.5" system on that should be fairly decent. As far as sound without the muffler, seems alot like it, the cats are supposed to give it a fairly decent tone.
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From: Rio Rancho USA
Yup, the engine will blow up if you take that muffler off.
Seriously, read up on backpressure vs velocity and flow and you will find your answer. To anyone that thinks they lost torque from just changing/removing the muffler and leaving everything else stock, think again. But then if backpressure is good, then a banana in the tailpipe must be great, right?
The butt dyno is NEVER accurate.
Seriously, read up on backpressure vs velocity and flow and you will find your answer. To anyone that thinks they lost torque from just changing/removing the muffler and leaving everything else stock, think again. But then if backpressure is good, then a banana in the tailpipe must be great, right?
The butt dyno is NEVER accurate.
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From: SW VA
Heh...I just need to talk my dad into letting me do it. For some reason, he was complaining the other day after cutting my friend's exhaust off...saying that it was $1,000 worth of pipes 
It was just a cat-back system with one Flowmaster 50-series. He doesn't want me to do it, because he thinks that's how much it will cost to fix mine. The stock exhaust exits in front of the passenger rear tire. After the muffler, its only a 2.5 foot section of pipe 
To put his old Flowmaster on, would only take an adapter, one clamp and a hanger of some sort. $10 at Advance.
It was just a cat-back system with one Flowmaster 50-series. He doesn't want me to do it, because he thinks that's how much it will cost to fix mine. The stock exhaust exits in front of the passenger rear tire. After the muffler, its only a 2.5 foot section of pipe To put his old Flowmaster on, would only take an adapter, one clamp and a hanger of some sort. $10 at Advance.
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Butt-Head
Joined: Apr 2004
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From: Reed Point, MT
I was going to say that if you REALLY want power, you need to stuff a potato in the exhaust pipe. Just make sure that it's completely sealed and you'll have so much backpressure that you might start popping wheelies.
However, I see that kens64 beat me to it.
Cody
However, I see that kens64 beat me to it.
Cody
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From: Prince George, B.C.
Thought I would add this to make a point. Today I was looking at a motorhome, Vortec 8100 powered Triple E Commander to be exact. I though I would have a look at the exhaust system as it has a 4"-4.5" tail pipe. It had dual 3" or 3.5" pipes into dual cats and mufflers that Y into the 4" tail pipe at the rear diff. What does a Chev pickup run on that engine? I was actually amazed at the difference in size of the systems. BTW, the low tone from that system actually shook the wash bay at work when we backed it out. I suppose though, you can't cheap out on a $250,000 dollar motorhome right?
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From: Reed Point, MT
The Chevy trucks with the 8.1L use a short (4" length) amount of pipe off of the exhaust manifolds that is 2.5". After that, the pipe off of each manifold becomes 3". The system remains 3" through a catalytic convertor (one per pipe) and 3" dual into the muffler. From there, it is a DUAL OUTLET muffler (3" each) and immediately into a "y" to ONE 3.5" tailpipe.
Cody
Cody
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From: Prince George, B.C.
So similar then. Its a heck of a system though. Don't know why more companies can't do somthing thing like that. Getting better flow is then just as simple as getting rid of the single tail pipe, and maybe better mufflers.
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Originally Posted by ATC Crazy
Heh...I just need to talk my dad into letting me do it. For some reason, he was complaining the other day after cutting my friend's exhaust off...saying that it was $1,000 worth of pipes It was just a cat-back system with one Flowmaster 50-series. He doesn't want me to do it, because he thinks that's how much it will cost to fix mine.
It was just a cat-back system with one Flowmaster 50-series. He doesn't want me to do it, because he thinks that's how much it will cost to fix mine.