stacks

[maverick_935]

Has anyone put stacks on a duramax? If so, are they worth it for economy, are they too loud for the neighbors or the highway.

Any thoughts.

[DmaxMaverick]

Yes. Several stacks on Duramax trucks. A few have been posted here over the years.
Economy??? How would (could) stacks benefit, in any way? They don't. Not to a degree you can measure without a dyno and very specific conditions, and precise calculations.

Unless you have a real world "need" to have the exhaust exit at that location (some do), it is 100% pure cool factor. Otherwise, a waste of bed space, unless you won't ever need the bed. Less than zero % ROI.

Now, if you are talking about through-hood stacks, that's very different. There is a performance gain. However, it's not legal, in any state, for highway use. In this case, you probably shouldn't be concerned with economy.

[maverick_935]

how can they boast economy and power increases?

[DmaxMaverick]

If there is a more free flowing exhaust, there may be a possible gain. Less back pressure is always desirable, with a turbocharged engine. The amount of gain is dependent upon too many variables to generalize it. In most cases, the gain won't be realized unless the transition is drastic (OEM to monster size, and a bunch more fuel). It depends on your current configuration, and the limit of your intended modifications. In the end, the ROI (Return On Investment) will still leave you with a net loss. If economy is your goal, look elsewhere.

[havenopower]

Stacks are really for looks. I have a 8 in stack. remember that the size of the output of the turbo 3 to 6 inches. most downs pipes dont get bigger than 4.5 inches not enough room. the only reason it sounds lounder is because it is closer to the cab not at the end of the box.