Okay the more I read, from what I understand, the higher the horsepower setting on your tuners, the better mileage you guys are getting? Is that right? that doesn't make a whole lot of sense to me, can somebody explain to me how this is possible.
Secondly, wouldnt the stock setting be easier on the engine? Or is it just a matter of how heavy you are on the foot feed or skinny pedal as of you refer to it?
I would love to get better fuel mileage by raising the power level on my tuner, but not at the expense of it being harder on the engine I don't think

 

The tunes can achieve better MPG by altering timing which can be very hard on the motor depending upon load.

If you want better MPG then buy a Toyota Prius.

 

thanks for the first part of your post,...but really,...im pretty sure everyone on here would jump at the chance of a couple more miles per gallon without going the Prius route

 

stock tunes find the happy medium for the power/weight ratio.. but this meduim also doesnt mean the engines running efficiently... more times than not with the newer vehicles the tunes are set to comply with the govt emission mandates..

aftermarket tunes tend to lean or richen the mix depending on what your going for.. more power wont always mean better mpg just as a leaner mix wont always mean better mpg.. every engine despite being made to the same spec have their own personality and will run differently from each other.. another part of the mpg also comes from the driver..

 

Agree with everything so far. Using a broad brush, yes the higher the diesel is tuned, the better the mpg. Almost seems like an oxymoron.

However, a lot of this gain is through timing advance and amount of fuel injection which translates to much higher combustion pressures.

Increased fuel requirements tax the factory lift pump system on our 6.4L's and starving the HPFP is the main reason for them failing.

Many are running the Hot Damn tunes on their 6.4's without issue. I have run those tunes and had issues. I am currently running a stock tune for that reason. IMO the mpg gains by higher tunes on these 6.4 aren't worth the wear on the engine.

 

My thoughts exactly! Like I said above, would love better mileage but not at the expense of wear and tear on the engine. Truck has plenty of power and not too bad on fuel so will continue to use the stock tune. Thanks for your input guys.

 

I gain 2mpg at 65mph vs 75mph, sometimes it is very easy and beneficial to simply slow down - not pushing so much air.

 

take the 7.3 for instance (i know 6.4 forum bear with me here..) they got better mpg if you were able to keep the rpms under 2K.. why was this?? because they were most happy/efficient around the 1600 rpm... engines running slower using less fuel but utilizing its torque to drive the trucks down the road... but the higher in the RPM band you go the torque starts to drop off making the engine less efficient and work harder with a higher consumption of fuel... this is part of why with the older vehicles you got your best mpg if you remained driving @ 55mph...

now with the 6.0's & 6.4's, the advancements in engine design.. the tq midrange for best performance (not talking race night performance here) sits right at 2K.. so depending on the gearing yes you could get your best mpg at 60 or 65.. if your rpms are right around the 2K mark.. but the faster you go still results in the same drop in efficiency above that mark..

6.7's depending on the article you read depends which spec you wish to believe... some articles ive read stated the 6.7's torque peaks at 1600 rpm, others state 1800 rpm... either way same result if you run the rpms up above this mpg drops off...

under the peak rpm tq range has the same result.. this is why (in combination with the lights and other crap) at city speeds your mpg will tend to drop as well.. its out of its happy zone for running...

 

Speaking of mileage and moving air, makes me think of this thread; https://www.ford-trucks.com/forums/1...erimental.html '

I have tried it, and at the time I was on the 300+ hp tune, I found it to be to much smoke/haze when taking off from a stop. You really had to feather the pedal. I guess I could try again on the stock tune, but the other issue is I hate having the engine light on it the dash - pet peeve.

 

very interesting reading. You said you tried it, what were your thoughts on it other than too much smoke taking off? Any mileage gains?

 

It was probably three years ago now, so I really can't recall. It seems that there was an improvement in mileage. At the time the MOE was pretty active here in Ontario, doing roadside checks to look for deleted trucks. I plugged it back in as I was doing everything I could to keep the tailpipe looking clean.

It seems to me that the MOE is not nearly as active anymore, I think that with the vastly improved reliability of the 6.7, with emissions intact, people are not deleting anymore and therefore the MOE isn't bothering to look.

Sorry I don't have any real numbers for you - it was too long ago.

 

no free lunch

economy requires leaner AFR
power requires richer AFR

miracles solutions like methonal injection (windshield washer fluid) just transfer the fuel costs from diesel to methonal. while true you get more power, cooler runnning engine, cleaner buring engine, better mpg, what you save in fuel MPG is offset by the costs of the methonal solution (wind sheild washer fluid).


also, cetane boost increasees the burn, some MPG increase, but the cetane boost costs will off set the gain. again, no free lunch.

becareful about adding power, with out adding cooling.