Stacks?

[JGrefenstette]

i was wondering, if i plan to build a set of 6inch stack for my truck, how should i go about making sure to get even distribution of exhaust through each stack? seeing how i would be most likley building them out of steel pipe, and wouldnt be using a nice factory y-pipe, how should i do this? especially sense i want to have flaps (rain caps) i dont want the passenger side stack to have the flap streight up at WOT and the driver side sitting at half mast. also abviously for smoke purposes it looks kinda stupid to have thick black rolling out one, and little random puffs coming out the other. im open to any suggestions.

my plan is to custom fab a 4 inch down pipe, then run 4inch flex up to the bottom of the bed then mate it to 6 inch steel pipe. i hope to get the stacks (everything thats in the bed at least) powder coated. i found a place a few hours away that does powder coating.

thanks for any input.

 

[16919]

Run the pipe to the center of the bed, then equal length to each stack

 

[daledozer]

I dont think your exhaust will open two 6" raincaps, I dont even think one. I have a 4"x8" piece of tubing on mine with a 4" short piece of pipe welded into the bottom to clamp the flex pipe onto.

 

[chuckwilson]

the easy way is to put a divider in at the split, good factory made y pipes have them in them, you can put one in were it comes threw the bed.

 

[JGrefenstette]

good idea chuck, i thought about that, the only reason i was hesitant is i want maximum flow an i didnt no if that would restrict the flow at all?



dale, you dont think the exhaust will hold up the caps? even if their wieghted properly? i guess i should expect them to bounce a little at idle when its cold, but i would think that @ 850+ rpms they would at least hover just above the pipe. i would be curious to know if your right though... i wouldnte be suprised.

 

[JGrefenstette]

oh and james... with out being under there its hard to remember, but i thinik i wanted to avoid the steight shot under the center of the bed because i would have to go under the frame rail... i want to try and eleminate as many bends and obstructions as possible. ill have to look closer at it though, it may be easier than im thinking.

 

[Forrest Nearing]

use a 5" Y-pipe with a splitter. On 2nd gens, it's hard to put it directly in the center. I always put mine one rib off center. requires using two elbows coming up vs. one, but always had nice even smoke.



don't take offense, but I don't think a splitter in a 5" Y is going to hurt power on your truck

 

[JGrefenstette]

so i should use 5" pipe even though im gonna use 6" stacks? i like the idea of using 4"x8" boxtube.



no offense taken what so ever i take that as more of a complement... hah



if i use boxtube would it work to use two slim pieces of like 1/8" plate and make a sort of wedge to place in the opening of the tube to evenly divert the flow?



is the sound any differnt through boxtube than it would be through pipe?

thanks a lot yall this is really good help

 

[JGrefenstette]

anybody got any pictures?

 

[Forrest Nearing]

I've done it w/ box before, and I also built a little divider in it. smoked nice and even

 

[JGrefenstette]

forrest you seem to have a fair amount of experience with stacks... have you any experience with flaps? do you think our little 5. 9's can push up 2 6" flaps?

 

[Forrest Nearing]

it'll push them up, but not at idle... I've never run flaps. I will say that I prefer the sound of a true Y pipe over a box, but the box is cheaper/easier

 

[JGrefenstette]

ok so theyll bounce a little at idle... not to big a deal to me.



now whats the real difference in sound of a box and pipe? if its hard to describe, dont worry, please use anywords that come to mind, it will make sense, im just trying to get a grasp of what the difference is your talkin bout here.

 

[Forrest Nearing]

more turbine sound out of the pipe... the box will cut down on resonance a little. the pipe is just more sharp and has more turbine in it.

 

[JGrefenstette]

ok then i think that answers my question. the pipe it shall be...

thanks for all the help forrest and the rest of yall.

 

[JGrefenstette]

well fellas, let hear your thoughts on this... last night i couldnt sleep, i finaly had a revelation about the y-pipe. i looked at the clock... 3a. m. oh well



here are my thoughts - purchase a streight run of probly 12-15 feet of the 6" pipe, cut 45*'s for mating the stacks on the main pipe, an then here is my break through for the "y". i think this should work. directly above where the exhaust comes up through the bed (on the oposite side of where it will 't', the top side) cut in a 45* wedge. . then take some 1/8" plate and lay it over each angle cut. trace it and cut it to fit, then weld it on. shouldnt this 'v' approach create a similar efffect to the 'y' pipe. i thought about cutting the corners off 2 elbows to the same effect, but this way seemed easier.



thoughts, ideas?

 

[Forrest Nearing]

it'll help, and you want to run that plate all the way down into the single pipe coming in so that you evenly devide the exhaust between the two sides.



I realize some of this stuff is pricey, but if you shop around online, you can get a 5" divided Y for $80 or so

 

[Greenleaf]

I love my truck w/stacks only because I have another one w/out stacks.



I never used a Y pipe. The first one I built uses a 5" steel box that serves as the base inside the bed. Two adapters (called reducers) welded ontop of the box convert 5" to 6" then the stacks.



The second set I installed I used all pipe. I built a "Boot T" at the base (inside the bed) and the elbows. The 4" pipe is then increased to 5" by way of "reducers".



The all pipe system is extreamly loud. The steel box is nice and mellow. Both smoke evenly but the "Boot T" has a diverter welded inside to allow for this.



You don't have to bring the bottom (feed) pipe into the center to achieve even smoke.

 

[JGrefenstette]

thanks for the wisdom and insight greenleaf. extreamly helpfull. i just got off the phone with one of my best friends. i forgot he has a set of stacks laying around in his barn that we had on his 05' cummins a year or so ago. their 6 inch mitre cut. im debating now, on either just using his 'y' pipe and making my own stack setup, or using his whole unit, i got an estimate onn powder coating the stacks, it'll be somewhere around $100. i am going to look around though to see how cheap i can come up with a set of old 6" stacks. im thinkin a junk yard. yank em off an old kenworth or somthing of the sort. at least now i have a good factory 'y' pipe.

 

[Forrest Nearing]

the closer to the center, the more even the smoke. when I came up over the stock pipe w/ a divided Y, the pass side would smoke a little sooner than the driver's



and just to reitterate, the box is much more mellow than the full pipe!



I really prefer the full pipe setup