The MPG tune will gain a bit. It dials back a lot of the torque management as well so there is a power gain as well.

I highly recommend running 89 octane with a Hemi. It is recommended in the owners manual and there have been some engine issues being damaged by unheard detonation in stock form (no tune). I have gained about 1mpg in town using the Predator MPG tune. Getting around 13.5mpg. I only live 3.8 miles from work so much of my driving is in open loop/ cool-rich mode.
I used to live 40 miles from my old job and got the best mpg with the 93 octane tune with 93 fuel.

 

My last tank of gas with the stock tune got 14.98 mpg which was just about my overall average since purchasing the truck last June. I installed the MPG Booster tune on 2/08 and proceeded to drive 354.2 miles on 23.40 gals of gas (Shell regular unleaded). My mileage increased slightly to 15.14 mpg. Not the stellar results I had hoped for.....but drive-ability was not degraded so hopefully with a couple of more tanks things will improve.

To be fair, I will run two more tankfulls before changing to the 87 Octane performance tune. Then, I will run three tanks with that tune.

 

My fillup on 2/13 gave me 15.14 mpg. My fillup on 2/22 went down to 14.80. One more tank this week on the MPG Booster tune and then I'm switching to the 87 octane performance tune.

Confidence is not high.....I repeat, confidence is not high,

 

My last tank on the MPG Booster tune gave me 15.51 mpg. That is about a 0.5 mpg improvement over stock. Nothing to cheer about.

I have now installed the 87 Performance tune and will test that for at least 3 tanks. Hopefully that will show a decent improvement in mpg.

 

interesting glad your doing this cause im tossing around the idea of getting a tuner. cant wait to see the 87 results

 

First tank on 87 Performance Tune and my mileage dropped back to 14.92. Disappointing to say the least. Going to run two more tanks on 87 Perf and then probably try a Custom Tune. I've located someone who has offered to assist me without charging an arm and a leg.

 

Well, things are starting to look up.....Just filled up and my mileage for this tank was 15.76 mpg. Not stellar but definitely an improvement. Especially since I had a little more in-town driving than I usually do. Hope that the next tank improves even more. If it does then I will keep the 87 Performance tune awhile longer. If not, then I plan to purchase a custom tune and see what happens.

 

Your heading down that rabbit hole fast. You just spent money 200-300 on used programmer. at your mpg gains, that will take a long time to pay off. Now dumping more money into a custom tune, another 200 ish maybe more IDK. And you still wont see gains over 1mpg, if you did, then the factory would be doing it from the get go.

Then that will take even longer to pay off.

Ive done E-fan(200), SC vivid(400), cat back(650), CAI(400), tonneau cover(1000). So ive got in alot of money on mine. and Ive maybe gotten 2.0 -2.5 mpg more on highway.
Ive noticed some nice power gains too, but the mpg savings will take me over the life of the truck to get back. But it also makes your truck unique and your own, so its not all about mpg, its about making it yours.

 

I was lucky to get my DSP for under $200. Really glad I did not spend $369+ for a new one. Have a line on a custom tune for a very very reasonable price.......that will be the limit for this mod/test.

I'd be very interested in the details of your efan if you wouldn't mind sharing.

 

Ya i really should have done a full pic tutorial while I was installing. Well onces its above freezing this spring. Ill take some pictures. Pretty simple install, gains seem to be noticeable, throttle seems quicker.

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