Stacks or back exhaust?
 

Hello everyone,

I've got a friend who runs dual stacks in his 94 F-250. We had a discussion regarding exhaust systems. He favors the stacks, saying it cools EGT by allowing a shorter distance for exhaust to travel. Although I'm not entirely fond of stacks, anyone have any ideas as to whether stacks make a difference? I know the diameter has a lot to do with it, but I'm scratching my head. Is there a performance increase with stacks versus normal back piping?

Stacks make ZERO difference in EGTs. After all there is only a 3" outlet at the back of the turbo, THAT is the limiting factor

Anything more than a 4" single exult is for looks and sound. It make ZERO performance gains

X2^^^^^^^^
I went from stock exhaust to 3" dp 4"exhaust which made a difference. Then went to 3"dp with 5" from the dp with 5" stacks and the only change was sound.

Dual exit pipes on any vehicle that, by definition, has single exhaust looks.... compensating. A SINGLE stack, done tastefully, can look right, but the real questions you gotta ask yourself are whether you want a hole in your bed, and whether you want the outlet that close to the cab and its occupants.

Come on guys you can't tell me this doesn't look totally rad lol
http://www.craigslist.org/about/best...493372708.html

This has to help with EGT's
http://i1213.photobucket.com/albums/...psbfxwzfxs.jpg

Alrighty, good information to know. Since I'm not a fan of stacks, it's nice to know I can use my 4" back piping without sacrificing some "magical stack performance booster".
Well, I'm okay with exhaust being that close to my occupants, however I don't like the fact that I'd have to remove a small amount of space in my bed for a stack. I use my truck for hauling heavy supplies, and I figure I'll use the space under the cab and bed that was given to me...
That thing looks down right weird AF. I know stacks are common, but CB whips and the whole dually thing? Nah.

That's always been why I won't go to stacks. The bed is too useful, especially on a 3/4 or 1 ton, to waste that space.

For the love of all that's right in this world, please, no stacks. My 2 cents...

...unless you do a hood stack! Otherwise, I totally agree.

Dude at our local farmers market has a stack setup I like. F-SD C&C with a frame set for a 9-foot bed (the C&Cs have those longer frames), put an 8-foot pickup bed on it, and has a tool box and a stack in the space in between. (Personally, I'd put a fuel tank in there if it were me, but....) Actually a pretty clean looking setup.

It has to be the right stacks on the right truck for it to not look tacky. Very fine line between "That's a sharp truck" and "Man, that guy is trying too hard"

All the really matters is if the person that is putting them on his truck likes them.
I had em on my 97 and they will be going on the dually and cN care less what anyone else thinks.

the only ones ive ever liked were ones that the stacks were the main uprights of a head ache rack

Stacks provide no performance gains over "normal" exhaust routing, IMHO. Stacks serve a purpose and I have no problems with the folks that run them. I keep a camper shell on my truck bed 99.99% of the time, so stacks are not an option for me.

If you're going to add stacks, do it because you want them. They won't add any performance value to your setup. On a side note, my local truck club has sponsored some "Dyno Day" events. The dynamometer shop personnel are NOT fans of trucks with stacks because they usually aren't setup to run a "stacked" truck on the chassis dyno. The shop is smoked out before the dyno run ends.

One thing to add to the fray is that generally with stacks you will end up with soot on whatever is nearby. Also, if you use a flat or mitre cut stack that allows water to collect in it, you will have all that sooty water blown all over your truck the first time you start it after a hard rain. I'm not a stack kinda guy, but to each his own. Personally I prefer a nice 3" downpipe to a 5" system that empies in the stock location. That's just my preference for look and sound.

As others have said, if you're going to do stacks, do it for the look and sound not for any expected performance difference because there won't be one.

Looks like a mobile pipe organ

I hear what you're saying but he did ask opinions and that's what we gave him. In the end it only does matter if he's happy but it sounds like he was on the fence.

He asked about performance gains, not looks

Yep, I stand corrected. I still hate them...LOL! But yeah, to each his own. I hate them so much I would almost sacrifice performance, even if they were better...but that's just me.

Do you guys think that a hood stack offers any kind performance gain? I would think maybe only a slight amount in higher horsepower trucks that move a lot of air (exhaust).

Phil, stacks don't offer any performance gain over the OEM routing. Consider that when adding stacks, one pipe is routed into two pipes. Generally with a double-90* turn, going to the left and right sides of the truck, and then additional 90* turns going up each stack. That's a minimum of 4 90* bends in the exhaust system.

I don't know what you mean by "hood stack," but that seems like a lot of sharp turns for the exhaust gasses to negotiate. Opening up the exhaust system is always better than the OEM setup. Stacks are just a different way to do that. They do offer better performance gains over an OEM system, but the do not offer better performance gains over a turbo-back system or a cat-back system. They're just use a different route and serve a different purpose.

What he means by "hood stack" is what you generally see on sled pulling or drag trucks. A stack in the hood of the truck, so exhaust only runs a couple feet max before going to atmosphere.

IMO, there can be a gain with a hood stack ONLY when the exhaust size being used is larger than you could have physically fit under the truck. On our hood stacks we are usually using a 4-5" pipe straight off the turbo and out the hood stack. Obviously, that's larger than what we are going to be able to build a downpipe with on most Powerstrokes. Dodges you can build a 5" downpipe for though. The hood stack itself is strictly for looks. Under the hood there is a pipe that is just blowing up into the stack. The stack and the pipe under the hood aren't physically connected.

OP, as far as stacks in the bed go... There will be zero performance difference. I have run a stack(s) on my OBS for about 8 years now. I have wished many times that I didn't do it, but there is nothing out there that is going to give me the same sound and it has benefits for me at the drag strip such as preventing me from "smoking the lights" (blowing the smoke up into the air instead of low to the ground where the smoke can blow forward and get in front of the timing lights).. Other than that, I like the look on some trucks and others I hate. On my truck, I like how the single 6" stack looks. I don't even care if Byron likes it or not. LOL :-drink

That's what I was thinking he meant, but wasn't sure. Thanks for the education, Travis.