deciding between 4 or 5 inch exhaust

[More Power]

I vote for a 4" system, good free-flowing muffler and a 5" chrome/polished tip... .

[EdHale]

We are certainly all different and I don't mean any disrespect to anyone, but I have never understood the desire for a chrome tip on any exhaust. That just seems like wasted money to me.

Of course at my ever advancing age CRS disease is sneaking up on me and maybe I just don't remember.

[gimpyhauler]

From what I've been reading, while there is more unrestricted airflow in the larger pipe, it also changes the power curve designed and programed for the vehicle as built. The larger pipe decreases the power at the normal zone we drive in. The "more power" is now both higher and lower than it was at our normal cruise speeds. Therefore, more power applied. I just keep reading the reports from the "regular guy on the street (smile) that while they love the new sound, their mileage always seems to be a bit lower than they hoped.

Since mileage is a significant issue in most buyers, and all brands being basically the same, if it was as easy as giving us just a little extra steel (cheap material cost) in a .5 or 1" larger exhaust pipe and gain significant improvements, would the big maker do it just to stand out as the best? I understand them going cheap on things like shocks, but something so cheap that would make them stand out on mileage just doesn't seem like something they'd miss. Not for something so high on all buyer's minds as mileage.

The only thing I've done lately to improve my truck is adding a new Bradford Built Flatbed after my OEM bed got smashed while parked and unoccupied in my driveway.

[bmoeller]

The decreased MPG is usually due to the increased pressure of the right foot while listening to the new noise.

[More Power]

The turbocharger is usually the biggest restriction in the exhaust system - for all non-DPF equipped trucks.

If I remember correctly, there was a proven power loss when a 5" exhaust system was installed in the middle-2000s Dodge Cummins trucks. To my knowledge, I don't know of a similar 5"/GM non-DPF connection.