2.25" or 2.5" dual exhaust

[zebra]

i'm planning on adding tail pipes to the truck and am considering 2.25" and 2.5" piping. i know it's a small difference, but i'm having trouble deciding which size to get.

when i had the 4.3, i was running a single 3" pipe from the y-pipe to a single in, dual out MellowTone muffler (similar to a FlowMaster50HD) and no exit pipes.

now that i've swapped in the 5.3, i don't know what it is - shorter stroke/smaller cylinders, more cylinders making more constant flow, or what - but it's just a lot smoother and a little quieter (unless i'm getting on it). now i want to add tail pipes to beef it up a little (and get a little more low-end torque back). the muffler has dual 2.5" outs, and i want a little more growl than a hollow-mustangy-sounding gurgle. i'll probably use some 3.5"x15-18" tips to deepen it up a little, but i just want y'all's opinions on which to go with.

just some application notes about the truck:
-it's my DD, so i don't need to lose any more fuel economy (if that would even be a factor)
-engine is a stock 5.3 with a tune & an up-and-coming CAI
-using stock manifolds, cats, & y-pipe with 3" pipe to the muffler
-it's 4x4 (with a 265/75-16 spare, soon to be a 285/75-16 when i get a new set of tires)
-i plan on a mild cam swap on down the road: something to bump the low & mid range
-since it ain't gonna be a HP monster, the flow differences between the different sizes is negligible, right?


thanks for the help

[low91]

I started with 2.25" duals with no X,H or any kind of balance pipe and loved it, for some reason I switched to 2.5" with an H-pipe and hated it, I couldn't believe how much low end I lost just from uping the pipe size.The responsiveness sucked and it sounded like something only a hillbilly with down syndrome would like. I switched back to my original setup and never looked back. I ran 2.25" on the 5.7L TBI that came in the truck with no complaints and will probably run 2.25" when I build a 6.0L.

EDIT: Sorry, just re-read your post and realized you were refering to a dual outlet muffler and not dual exhaust, in which case I have no clue. Though I doubt it would make a huge difference since its after the muffler.

[zebra]

thanks for the feedback. i edited the title to clear that up a little.

if i was doing a full setup, i'd go with 2.25" because it ain't any kind of exhaust-breathing dragon or anything... just a stock~ish 5.3

[txarkitekt]

Dual 2.5" is gunna be too much for the stock-ish 5.3L. I am gunna say to roll with the 3" to the muffler and run 2.25" to the tailpipes.

[blueflamed03]

found this before, how relavant is up to what you read into it

[zebra]

nice chart... is that based on crank HP or wheel HP? that would make a huge difference

so far it's looking like i'm going with 2.25" and i reckon once the cam's in i'll re-evaluate how it's holding up (probably be fine).

does anybody have anything similar to this that i could see/hear?

[blueflamed03]

oh I'm sure it's crank. For sound, 2.5" dual pipe will sound best, but it's up to you, power, or sound.

[zebra]

well the way i see it is that the 2.5" might be too big & give me that hollow gurgley sound, which i don't want. since, according to that chart, the 2.25" would flow better/have better pressure for my motor & it'll give a little more definition to my exhaust note, the smaller pipe sounds like the better option.

now i'm to the point of trying to find somebody with a similar setup that i can hear a video of