pull-do

Thinking about getting rid of the stock exhaust and going aftermarket,,, hoping to squeeze a little more mileage out of it,, anybody else do this with their '07,5.9 and if so,

1/did it help any with the mileage
2/what are the other benefits

I don't won't a loud truck,,, I'm old, , don't mind a little noise just don't want the drone inside the cab

Spooler

You won't gain a thing with mileage. Just replace the muffler if you want, but it will be louder.

PoorMansCat

x2... you won't get one single mpg from exhaust. You won't get anything from changing the intake plumbing/air filter/ filter housing either.
The benefits are a better sound.
If mileage is what you are hoping to increase, I would suggest a Smarty Jr.

rockcrawler304

Ding! Ding! Ding!

Spooler

We have a winner...

pull-do

Bout what I figured,, so if I get the smarty, anything I should do in addition, don't tow that much, so would I have to worry about EGT's or anything in particular,,,,,, no gauges, and I didn't really want to put them in if they're not needed

Can you get the same results with a second hand smarty or do you need to get a new one?

PoorMansCat

Gauges are nice to have.. I have them, but I tow alot. If you don't tow much, and the loads you pull arent that heavy, then you probably don't necessarily need gauges.
But, if you set the Smarty Jr. to the higher levels, I would invest in an EGT and Boost gauge.
I'm not 100% sure but.... I believe if the Smarty Jr is used, the truck it used to be on MUST be returned to stock programming first and the SJ cant be VIN locked.

pull-do

Another ?, on the smarty jr,,, say I don't like the results, I guess you physically take it off and it goes back to stock settings,, has anybody ever had their truck not go back to exactlly to the way the truck preformed at stock,, mileage wise and so on, or is there a chance it'll change something and it not be the same,,

just curious, like the way the truck runs now and not bad on the mileage, just trying to get a little more (mileage) out of it.

cstewart

Pull-do,

As said before, it seems that a Smarty Jr is what you will be looking for with respect to mileage gains. That said, I can't imagine that you won't be satisfied with the diffrence in performance and more importantly drive-ability. HOWEVER, if you did decide to go back to stock, it sould do just that without any after-effects. You just simply turn your truck back to the stock setting using your smarty programmer plugged into the ECM. (the Smarty is used as a tool to update the ECM...it doesn't stay plugged in to the truck)
Just a warning...if you drive your truck for even a minimal amount of time on ANY of the Smarty Jr settings and then go back to stock, I think you will find yourself fairly dissapointed in the power difference (I thought my truck was pretty quick before I got the JR..."why didn't I do this years ago" was the only thought afterward.)
Going back to your original post...I echo what the other guys said. Your stock exhaust will be fine. The one "imature vice" I have is the fact that I did go with the 5" MBRP turbo back...it's exclusively for the sounds (it's MUCH louder than stock. And my wife reminds me of this daily )
If you go the Smarty route, let us know your thoughts...! Good luck...