stack issues
Elder User
Joined: Apr 2002
Posts: 950
Likes: 2
From: West Bend
Is it easier to pass gas if you first stick in a butt plug?
I don't buy it. People will also say "You make more power with back pressure"
Sure some engines will make more power with a smaller exhaust than a bigger exhaust, but it's not due to back pressure, it's due to flow velocity. It's also why your intake and exhaust valves are open at the same time - the velocity of the exhaust flow helps pull in fresh air from the intake and scavenge the cylinder to clear it out of left over combustion products from the previous combustion cycle. Turbo engines get by with less overlap because the forced induction can help scavenge the cylinder clean without depending on the exhaust flow to suck it out.
left over byproducts from the previous combustion cycle equates to 0 power gain on the subsequent combustion cycle and only equate to power loss. (and lower combustion temperatures and nox production if you get into the emissions side of it)
All you have to do is look at how many race cars run open exhaust, and they run their engines harder for longer periods of time than we run 'em on the street.
I don't buy it. People will also say "You make more power with back pressure"
Sure some engines will make more power with a smaller exhaust than a bigger exhaust, but it's not due to back pressure, it's due to flow velocity. It's also why your intake and exhaust valves are open at the same time - the velocity of the exhaust flow helps pull in fresh air from the intake and scavenge the cylinder to clear it out of left over combustion products from the previous combustion cycle. Turbo engines get by with less overlap because the forced induction can help scavenge the cylinder clean without depending on the exhaust flow to suck it out.
left over byproducts from the previous combustion cycle equates to 0 power gain on the subsequent combustion cycle and only equate to power loss. (and lower combustion temperatures and nox production if you get into the emissions side of it)
All you have to do is look at how many race cars run open exhaust, and they run their engines harder for longer periods of time than we run 'em on the street.
Elder User
Joined: Apr 2002
Posts: 950
Likes: 2
From: West Bend
Yeah I've got a 4" pipe as well and my turbo takes a fair amount of bite out of the noise but I still wish to quiet it down some. It currently exits ahead of my rear wheel but I've got a pipe to take it out behind the rear wheel. I'm hoping that helps a bit and then I'm going to add some sound deadening material inside the back of the cab. If I want to quiet it down some more after that it'll get a Dynomax. I love how they sound (especially when you work 'em) but I don't like loud either!
I've gotten quite a few comments from outsiders about how nice it sounds.
I've gotten quite a few comments from outsiders about how nice it sounds.
Postmaster
Joined: Apr 2009
Posts: 4,086
Likes: 1
From: Malahat/Cowichan Valley
if its a gasser you can float valves and kill the motor, my dad did that on his 69 chevelle SS when he first bought it and straight piped it. About 2800 miles into his new car he had to replace the engine, but back then 325 would get you a new one, hell right off the showroom floor he only paid 3800. lmfao!!! Diesels are a different breed, especially our idi's, you could use 55 gallon drums for exhaust and they would only get happier!! lol.
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1979F350/460
1973 - 1979 F-100 & Larger F-Series Trucks
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Nov 9, 2012 05:50 PM
