contradicting header info
Cargo Master
Joined: Nov 2003
Posts: 2,585
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From: Duluth, Mn.
From what I've read, the headers are not worth the money. $500 for 5-8 HP.
Checkout the Auto jet 3" exhaust. Comes with a mandrel bent y pipe, and freeflow muffler. Around $300.
Your money would be better served buying a used turbo setup. They go for under $500 on ebay, all the time.
Checkout the Auto jet 3" exhaust. Comes with a mandrel bent y pipe, and freeflow muffler. Around $300.
Your money would be better served buying a used turbo setup. They go for under $500 on ebay, all the time.
Freshman User
Joined: Oct 2006
Posts: 42
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Originally Posted by CheaperJeeper
...
If it is 2.25" pipe, duals would give you 7.05 square inches of pipe to flow through.
If it is 2.5" pipe, duals would give you 9.85 square inches of pipe to flow through.
A single 3" exhaust gives you 7.08 square inches of pipe to flow through.
So even if the stock pipes are 2.25" doing the duals is still the equivalent of putting a 3" system on....
If it is 2.25" pipe, duals would give you 7.05 square inches of pipe to flow through.
If it is 2.5" pipe, duals would give you 9.85 square inches of pipe to flow through.
A single 3" exhaust gives you 7.08 square inches of pipe to flow through.
So even if the stock pipes are 2.25" doing the duals is still the equivalent of putting a 3" system on....
Ken
Posting Guru
Joined: Aug 2006
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From: Kent WA
Originally Posted by IHWillys
Two pipes are more restictive than one, given the same cross-sectional area. This is related to the ratio of the cross-sectional area to the surface area of the pipe. Dual 2.25" pipes will not flow as well as a single 3".
Ken
Ken
However, the difference is going to be pretty small, since we're talking about a gas (rather than a liquid), and given that fact, I think it's still pretty safe to say that the difference is going to be minimal. The biggest issue is having enough volume/space for the escaping exhaust to have somewhere to go.
Pretty safe to say that the difference would definitely be small enough that two 2.5" pipes will flow better than a single 3"...
Posting Guru
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From: Kent WA
Originally Posted by fonefiddy
....Checkout the Auto jet 3" exhaust. Comes with a mandrel bent y pipe, and freeflow muffler. Around $300....
Do you have a picture?
Posting Guru
Joined: Aug 2006
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From: Kent WA
Originally Posted by chewyjackson
Can the dual pipes off the headers be bigger than a 2.5"? What if both pipes were 3"?
Trouble is there isn't a pathway alongside the driver's side to run a pipe to the back. Too many things in the way (fuel tanks for one). You might be able to do it, but you're going to end up with your exhaust pipe running under the tanks and crossmember. The solution some have come up with is to run duals but run them both down the passenger side in the location of the original exhaust.
can't see how it would be possible to run two 3" pipes through there - especially in the area where it goes up & over the crossmember. My single 3" doesn't have all that much room to spare, and even dual 2.5" pipes will be a tight fit. Particularly in the area of the crossmember.
Posting Guru
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From: Kent WA
Originally Posted by fonefiddy
From what I've read, the headers are not worth the money. $500 for 5-8 HP...
WAY better than any 5-8 HP....
Posting Guru
Joined: Jan 2007
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From: shawnee KS
What size is the stock exhaust on my 85 6.9? I had a local muffler shop run duals on my truck, although I don't remember the diameter. I remember it did wake the truck up though, can't give numbers, no use of nor money for a dyno check. It brings up another point though. Aren't diesels designed to run with some backpressure? I'm running what Walker called at the time a "turbo tube", which I am sorry to say I can't find anymore. They are very loud on my truck, but the sound is beautiful. I ride also, and I've been behind my truck going down the road before, and let's just say it's not a pleasant place to be on a motorcycle. Anyway, how much backpressure is needed, if any? Because there is very little to my mufflers, you can look right through them. Another exhaust thought, how about an "H" pipe in there somewhere? On the other hand, true dual exhaust gives the opportunity to the owner to diagnose which side of the motor could be having problems simply by the differences in smoke on the two sides. If you are sucking air on an injector for example?
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Posting Guru
Joined: Aug 2006
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From: Kent WA
Originally Posted by cfrives3
What size is the stock exhaust on my 85 6.9?
Originally Posted by cfrives3
I had a local muffler shop run duals on my truck, although I don't remember the diameter. I remember it did wake the truck up though, can't give numbers, no use of nor money for a dyno check.
Originally Posted by cfrives3
It brings up another point though. Aren't diesels designed to run with some backpressure? I'm running what Walker called at the time a "turbo tube", which I am sorry to say I can't find anymore. They are very loud on my truck, but the sound is beautiful. I ride also, and I've been behind my truck going down the road before, and let's just say it's not a pleasant place to be on a motorcycle. Anyway, how much backpressure is needed, if any? Because there is very little to my mufflers, you can look right through them.
Originally Posted by cfrives3
Another exhaust thought, how about an "H" pipe in there somewhere? On the other hand, true dual exhaust gives the opportunity to the owner to diagnose which side of the motor could be having problems simply by the differences in smoke on the two sides. If you are sucking air on an injector for example?
Last edited by CheaperJeeper; Jan 23, 2007 at 08:25 PM.
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From: shawnee KS
They are ran down the passengers side. And hey cool about the whole "see thru". Mine are about a see thru as you can get. No packing at all even new. But they are loud. That truck was my neighbors alarm clock where I used to live.
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From: Kent WA
Originally Posted by bc6.9
I can tell you for a fact that running a single 3inch exhaust does not compare to running dual 3inch exhaust....it was the single biggest bang for my buck compared to any other mods that I have done!
Last edited by CheaperJeeper; Jan 23, 2007 at 09:45 PM.
Posting Guru
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From: Kent WA
Originally Posted by bc6.9
Yes, both down the passinger side, the boys did a great job, sorry no pics.....you should of looked at it on Sat.