Bullydog for mpg? More power?
 

I have a 2003 dodge ram, was gutless after I had the battery cables off, no bullydog unit left the PO took it out when he sold the truck.

Anyways I've been trying to get the fuel economy display to work, it is out because the barometer reading is not good, the gauge is maxed out, but tech support said the truck will get best MPG on performance setting. Can anybody verify this? I thought no power would have been best but he insists because of extra timing advance it will be more efficient. The cylinder temps see to be a few hundred degrees higher which I thought mean using more fuel but I don't drive it enough to get a tank to tank change, plus its freezing here.

Is there an obd2 port splitter so I can plug in a tuner and a scan2 unit at same time?

I'm only really clear on your question, and yes, there are splitters. It works for my UG and SCii at the same time- not sure about your situation.

http://www.amazon.com/s/ref=nb_sb_noss_1?url=search-alias%3Daps&field-keywords=obdii%20splitter&sprefix=obdii+sp%2Caps&r h=i%3Aaps%2Ck%3Aobdii%20splitter

Bullydog tech support says the truck gets better mileage on performance setting. Anybody have a real life experience that proves that? Doesn't sound right

People on the VW TDI sites will make the same claim, but there are too many variables and too little actual testing to verify. As far as I know the turbo diesel piggyback boxes can only affect fuel pressure and injection timing, so I doubt very much that engine efficiency can be changed in any meaningful way. But if the factory injection timing is conservative to allow for use of low cetane fuels, some advance with good fuel may improve fuel mileage.

The VW folks are in the habit of replacing injectors and turbos, so those can certainly make a difference as well, but the way they drive afterwards negates any potential benefit.

My guess is what they are tell you is correct. Just keep your foot out of it when you have it "power" setting.

Some of the gen 2 insight owners find they get better mpg with the car in normal vs eco mode and taking it easy.

Id google your truck. I hear soo much about mods for better performance and many for diesels result in better mpg. Many center around the water cooled egr delete. The older w123 mercedes had some screws you can adjust on the injector pump for either performance or mpg.

I can get better mpg on my Subaru wrx sti in performance mode than eco mode. This is because performance mode allows me to pulse faster, thus I can glide way longer.

In eco mode, since power is less, my pulses are just as long as my glides.