Fixing to get triple Bully Dog Programmer. I was woundering if I should change exhaust or can I leave the stock. Have many friends with both just looking for the best combo. Not pulling nothing just looking for more MPG with the price of diesel. Roll about 30K a year.

BTW: 05 F-250 6.0L PSD

 

Sorry, but why run a tuner if you're just looking for fuel mileage? Look at the big picture:

30,000mi. / 13mpg * $3.00/gal = $6,923.08
30,000mi. / 14mpg * $3.00/gal = $6,428.57
30,000mi. / 15mpg * $3.00/gal = $6,000.00
30,000mi. / 16mpg * $3.00/gal = $5,625.00
30,000mi. / 17mpg * $3.00/gal = $5,294.12

Let's say you get 15mpg now, and you get 17mpg after the tuner (you're not likely to see 2mpg out of this). You're spending, what, $500 for the BD triple programmer? And the exhaust is going to run you another $500-$1K once installed? It'll take you over a year at these rates to make up the cost of the equipment/installation, plus you're running the engine and transmission harder, and you stand an excellent chance of having your warranty voided (I've heard several mentions that the Bully Dog is very "detectable", even if removed, unlike the Superchips/SCT/etc. units). Even a small repair out of warranty is going to put you in the red on this deal.

30,000mi. / 15mpg * $6.00/gal = $12,000.00
30,000mi. / 17mpg * $6.00/gal = $10,588.24

Even if diesel goes to $6/gal (God forbid...) you're still just barely breaking even in year one. At these prices, it's still a very questionable decision (considering a new 6.0 is $12K and a new tranny is $3-5K.)

Just my $.02.

 

In addition to the above let me add that doing performance modifications (and, let's be honest, that's what they really are) for fuel economy reasons is much like super sizing your value meal just so that you can get an extra large diet soda. It's a losing proposition.

None of the popular modifications do anything to change the physics of the entire situation. You are still trying to move/accelerate roughly 7,000lbs of truck. You are still dealing with a drivetrain that is only X% efficient--with power being lost with each step through the drivetrain. And, you still have a truck with the rough aerodynamics of a brick; which leaves you with the same rolling & wind resistances to overcome.


Hypothetically speaking, let's say that you do manage to net some measurable & consistent improvement in fuel economy. Every time you get into the throttle just for a bit--whether it be to pass someone, merge with traffic on an interstate, just to feel the acceleration, etc.--it will take some extremely conservative driving over many, many gallons of gas & miles to recover from a couple seconds of lead foot.

 

That's about the best analogy I've ever seen re: Performance Mods.

You'll never be able to keep your foot out of it

 

With an intake and exhaust and prudant driving +2MPG is very attainable. Now, taking that with a grain of salt in the context of the replies above this one, I will have to admit that most folks that are buying a tuner/intake/exhaust will use the fuel economy gains as a means to justify to themselves or to thier better half that this is a not only a purchase being made for fun and sport...but we are also gaining fuel economy to boot! The truck will be more fun to drive, safer to drive especially in a panick situation, and will last as long as any of the non tuned trucks out there. I have a number of personal friends with Cummins, Duramax's, and PSD diesel that are tuned, piped, and have intakes..and they are work trucks that pull bobcats and other construction equipment with them and they have 100-300K miles on them with nothing but the usual wear items.....rear ends and tranny's every 100-150K miles and other misc junk that we all have to deal with. If you want to get a tuner because you think its going start slamming fuel cash back into your pockets, you are not being realistic. If you want to make your new toy an even more fun new toy, and know that in a year or two the mods will end up paying for themself.....in fuel savings and fun factor.....your on the right track.

As for warranty, that's a personal issue, some guys swear it voids the warrany, our local dealer sales lifted trucks with aftermarket exhaust and tuners off the lot and we take our trucks in for service with tunes/intakes/straight pipes on them and the guys there love what we have done. Its all in the attitude of the shop and your relationship with them. You will hear differant views, dont forget to form your own views....