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Discussion Starter #1
I wanted to use magnaflow dual in/dual out muffler and have it exit the same spot where the factory exit's. I have a 2007 K/C which has duals to the muffler then after the muffler is single. If I got hold of someone's stock pipe and just have one side pipe a little longer so it can exit behind the stock location but would be a true dual? Would the 2.25 inch pipe to the muffler fit under the 2.5 inch muffler pipe? What does everyone think?

http://www.hottexhaust.com/detail.asp?PRODUCT_ID=14568
 

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Discussion Starter #2
Bump.... Does anyone have some imput on this? I really think that our Titans perform better without a true dual? Any body concur or disagree?
 

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I have been studying exhaust a lot in general lately and here is what I believe.

1. Your first major restriction is going to dictate how the exhaust performs in general.
If that major restriction is the factory cat, you are done with any major exhaust tuning at that point. That's not to say that taking other restrictions out of the exhaust won't help, it will, but not nearly to the degree it would have without the first major restriction. A chain is only as strong as it's weakest link and all that.

2. Part of Exhaust tuning is about one side helping to scavenge the other side and equal length is better than conflicting lengths for this.
Just exactly how much equal length helps to scavenge vs conflicting lengths is a mystery to me but it is better. The exhaust pulses going through a properly sized H and preferably an X pipe will help to increase overall flow of the exhaust and duals are a great place for an X pipe. In place of an X pipe for dual into single, I am going to get the Dr gas convergence Ypipe to help scavenge and change the note of the exhaust slightly.

3. Random turbulence is your enemy and mandrel bends are superior to crush bends.
How superior is the question because I have seen figures ranging to as much as 35% better flow. I have also seen some people say they change to larger pipes on the crush bends and that makes up for the change in size. I'm not buying it because a properly sized pipe with a mandrel bend makes a lot more sense to me than an over sized crush bend ever will.

4. Size does matter, in this case the proper size.
like a lot of things, balance is the key to a properly flowing exhaust. Too big a pipe and you loose velocity of the gas, to small a pipe and you loose volume capacity creating back pressure. I think on our pipes 2.25" may be the sweet spot but as with most things regarding our exhaust, it is debatable. If I ever go true duals, that's the size I will put on. In the case of the dual into single my headers are 2.25" collector and my bpipes are 2.25" (crush bends, yikes) and I think I am going to have the custom equal length y pipe made of 2.5". I think by stepping the exhaust we will also create a higher velocity of exhaust gases.

Is all this stuff correct? How the heck should I know, lol, but this is what I choose to believe after my research into the mysteries of the exhaust system. After everything is said and done, there may only be a 5HP difference between what I consider to be a properly designed exhaust and crush bent pipes. I bet in the end my exhaust performs well and sounds fantastic though and that will be worth the aggravation and cost to me. My truck is a hobby, a keeper, and I will drive it till the wheels fall off and then some so I'm willing to go the extra mile.
 

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Discussion Starter #4
Thanks for the imput papa d, for now I'm using a Magnaflow dual in- single out. I will upgrade after coming back from deployment and I will keep in mind what you told me here again thanks.
 
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