question about dual exhaust
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Junior User
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From: Macclenny Fla
question about dual exhaust
Hello everyone I just bought a 86 F350 with a 6.9L diesel,This is my first diesel. The question I have is, will dual exhaust help performance and fuel milage? If so what size exhaust would Yall recommend?
Thanks in advance. I have been lerking but this will be my first post//
Thanks in advance. I have been lerking but this will be my first post//
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Joined: Jul 2006
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From: Hesperia, So Cal
everyone around here says to go with a dual 3 inch exhaust, or a single 4 inch, but remember just beacuse youve opened up the exhaust and are letter more out, youll have to open up the intake, so you can get more air......i would go for the "ram air" setup that alot of people on this forumn have, and say they help out alot, some one should be by in a few to give you some technical mathematical equation on both exhaust setups, and air flow, and get you some pictures of their ram air setup.... after you do both of these upgrades, you can turn your fuel up a bit and get a lil better HP, but when altering your fuel adjustment, youll want to install a pyrometer to watch engine temps.....
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From: New Jersey
If you're using the cast iron manifolds, IMO you're better off with a big single pipe than smaller dual pipes. The single pipe setup (properly configured) creates "scavenging" where the exhaust pulses in the pipe help draw exhaust gasses out of the other cylinders. If you want to do that with a dual exhaust, it's best done with headers. Cast iron manifolds don't scavenge well. With headers, the collectors at the end of the header tubes create the scavenging effect that help evacuate exhaust gases out of each bank of the engine.
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From: Powell River B.C.
I have ram air, headers, and pictures on my gallery. Have not had to turn up fuel as I feel I have plenty of power with the set up I have, plan to spend a bunch of money to get there though. With a 6.9 even if you get a single 3" fabricated up to and including the Y pipe you will be power ahead for least amount of money spent.
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From: Hesperia, So Cal
yes dave i was talking about you lol, im a bit surprised you didnt get some pictures up and give him those air flow numbers, i would have, but have no idea how to lol......i just read through my last post, and i think i may have sounded a bit rude, if i did, i apologize!!!
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I had single 3 inch exhaust, went to the duals and wow, what a difference and I immangine it would be even better with headers....if your going to install a turbo down the road, 4inch is the way to do go!
The boys are right on when they say you have to open up the intake and far as pulsing[?] well I can't really say if I have any of that.
The boys are right on when they say you have to open up the intake and far as pulsing[?] well I can't really say if I have any of that.
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Joined: Jan 2007
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From: East of Neckville NC
Originally Posted by KJLYPW
I have ram air, headers, and pictures on my gallery. Have not had to turn up fuel as I feel I have plenty of power with the set up I have, plan to spend a bunch of money to get there though. With a 6.9 even if you get a single 3" fabricated up to and including the Y pipe you will be power ahead for least amount of money spent.
thanks!!!!
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From: Macclenny Fla
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From: Powell River B.C.
www.stans-headers.com Look under their stock headers, Ford, P/N 269. web site has contact numbers.
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From: Mississippi
Originally Posted by KJLYPW
I have ram air, headers, and pictures on my gallery. Have not had to turn up fuel as I feel I have plenty of power with the set up I have, plan to spend a bunch of money to get there though. With a 6.9 even if you get a single 3" fabricated up to and including the Y pipe you will be power ahead for least amount of money spent.
speedrdr
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From: Mississippi
thanks much!!!! killer looking setup there. one question for you though, does the hood make up the top portion of the intake scoop? i'm thinking that all the air comes through the grille in front and goes up and into the tunnel, making the hood the top seal for the front portion of the intake box. maybe i'm just looking at it crooked.
speedrdr
speedrdr
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From: Powell River B.C.
I have rubber baffles on the sides of the front of the scoop to trap the air creating the ram effect, these all fit tight against the hood, which has that portion of the insulating blanket removed and metal taped edges for smooth air flow. I have measured with a manometer 3 times the air pressure over what was entering the stock set up.