Suddog

iTrader: (10)

Thanks guys for the inputs...I will be going with the 2.5 duals and I will have the shop put in an H just for good measure.

Suddog

iTrader: (10)

I went with 2.5 and no H pipe. Pictures and video will be coming. It is so much quieter! Surprisingly no drone what so ever. Muffler shop sucks, but it's functional. I love the sound of the Magnaflow.

zero2sixT

iTrader: (4)

Glad you like it. Post up some pics

If you can, coat the pipes in cooking oil, start the truck, and watch where the cooking oil bakes off first. That is where your restriction is, and where you should put your balance pipe.

Ok, not trying to **** on this thread. I'd just like to explain my thinking. Hopefully someone can give me an explanation on why I'm wrong. I think the information would benefit anyone who is deciding on an exhaust setup. I searched a little bit, but could not find a definate answer on why a dual 2.5" > single 3". I found a sticky on tech where an OP (also a mod) stated going from a good cat back to true duals was a waste.

I agree that 2 equal, straight lengths of 2.5" piping will outflow a single, straight piece of 3" piping of the same length. I don't see where that explains 2.5" true duals over a 3" single.

First, not sure of ebay header collector size, most I've seen were 3" collectors. Wouldn't going from 3" collectors to a 2.5" pipe create a restriction? And then hurt the scavenging effect in the heads?

I have one bend in my exhaust setup. I'm pretty sure a true dual setup is going to have more. I was always under the impression, the less bends the better.

Also, going from a 2.5" pipe to a 3" muffler inlet would create a lower delta p. But a pressure drop will also create a delta T. Wouldn't a lower exhaust temp also hurt exhaust flow and/or performance?

Doesn't a true dual setup have a muffler for each pipe? Wouldn't 2 pipes to one muffler create another restriction?

Suddog, if I'm pissing you off, sorry. Let a mod know, I have no problem with this post getting deleted. I'd just like a little more proof on why I'm wrong.

Suddog

iTrader: (10)

No problems at all. Everyone has a different opinion and I appreciate your input. I asked for opinions and everyone gave theirs. Ask ten people how to make a truck go fast...get ten different answers.

You are right, it is not true duals. I didn't even think about that.

I was all for the 3" dual as I thought I needed it. I do agree that going from a 2.5 pipe to a 3" opening will allow the gas to expand and then get compressed again slightly before exiting the tail pipe. In my opinion, what I did was in essence make my muffler act a tad bit bigger. Gases will cool slightly after expanding and the velocity will slow down a bit.

DR132

plain and simple most of your gains are made when you remove your major restrictions (stock muffler, cats if possible, stock iron manifolds) what you do with your exhaust pipe and muffling (assuming you use high flow mufflers) is honestly mostly for sound and aesthetics. you may notice some differences between 3" single to 2.5" duals to 3" duals and various mufflers on a dyno but most of the difference you might notice driving is usually imaginary. for the typical small block V8 anything bigger than 2.5" single is plenty. once you've opened up the exhaust that's that, you're not getting any more. in short, differences in flow of different sized unrestricted pipes (in the common exhaust sizes) are negligible on the road IMO.