I could care less about my neighbors. So i was just wondering what other ppl in Pa do?
but i doubt it Pa sucks and won't let us have any fun.
4 inch or 5?
Postmaster
Joined: Apr 2005
Posts: 2,759
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From: round rock, tx
Originally Posted by messeswithtrux
we dont have inspections where i live, and i dont give a damn about my neighbors, so 5 inch straight it is. what the hell, why not.
It costs $25 each 6 months (IL)
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Postmaster
Joined: Jul 2006
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From: Indianapolis
Hey Mustang- my truck came from PA, and the guy I bought it from had a Magnaflow system on it, with no cat. I then came out to California, and ditched the muffler. I do keep the muffler in the back of the house incase I ever sell the truck I can give it with them. You can get a muffler delete pipe, of for probably even cheaper go to a muffler shop and have them make you one from scrap for a few bucks. That way if for some crazy reason you don't like the sound, you only lost a couple of bucks.
Laughing Gas
Joined: Jul 2004
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I have just cut my muffler off last week, still runing the factory down pipe though. I love the way it sounds with just the small factory stuff and i know i would like a straight 5" but i was just wondering how the Pa inspections would like it. my truck is a 99 built in june so it never came with a cat from factory so i won't need one for inspection. And i was helping my uncle tear down his outdrive on his boat today and didnt make it to the local inspection station to check out if i can go muffler-less.
Fleet Owner
Joined: Jun 2004
Posts: 25,090
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From: Rio Rico, AZ.
There is no replacement for displacement.
There is no substitute for a 5" pipe either.
Crack, the only thing that sounds better than the 5" in a tunnel is pulling the trailer up the pass, engine at WOT at 2400 rpm.
ALL of the exhaust flutter is gone and it's a screaming, whistling, snarling beast!
I just returned from a 4000 mile trip and was treated to a LOT of music on the hills.
There is no substitute for a 5" pipe either.
Crack, the only thing that sounds better than the 5" in a tunnel is pulling the trailer up the pass, engine at WOT at 2400 rpm.
ALL of the exhaust flutter is gone and it's a screaming, whistling, snarling beast!
I just returned from a 4000 mile trip and was treated to a LOT of music on the hills.
Postmaster
Joined: Jun 2006
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From: Fulltime RVer
Ok, here's an overview of my preliminary "engineering assessment" of the impact of tailpipe diameter on engine performance that I'm including in the next generation of my PSDEM, which will among other things model the effects of TBP= Turbine Back Pressure, psi.
TBP=(some other stuff)*[(cfm)^2][(1/D)^4][(L)]
So for simplicity consider a fixed length L of straight pipe, with diameter D flowing cfm of exhaust gas. So, increasing from 4" to 5" can theoretically decrease TBP by a X2.44 at the same cfm! I won't get into the details of how this effects engine performance, because I'm still working on those, but we all know the importance of flowing as much air as possible into the engine, and when you add some fuel mass to that mass of intake air, an even higher mass gas flow comes out the tailpipe, and a 5" pipe will flow X1.56 times more cfm than a 4" at the same TBP!
Now if you put a muffler or CAT in front of the larger pipe, that's another story, but wife is saying to turn off computer or else!
TBP=(some other stuff)*[(cfm)^2][(1/D)^4][(L)]
So for simplicity consider a fixed length L of straight pipe, with diameter D flowing cfm of exhaust gas. So, increasing from 4" to 5" can theoretically decrease TBP by a X2.44 at the same cfm! I won't get into the details of how this effects engine performance, because I'm still working on those, but we all know the importance of flowing as much air as possible into the engine, and when you add some fuel mass to that mass of intake air, an even higher mass gas flow comes out the tailpipe, and a 5" pipe will flow X1.56 times more cfm than a 4" at the same TBP!
Now if you put a muffler or CAT in front of the larger pipe, that's another story, but wife is saying to turn off computer or else!
Last edited by ernesteugene; Jun 17, 2007 at 10:54 AM.
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