hey sorry if this has been talked about already, but I have searched and couldn't find anything about it really. I have a 06 with 5.4L +6" lift, 35's and evo. In the city I get about 14.5 mpg which is descent from what I read. But on the highway I only get 15.5 +/- .2 is there anything i should change in the evo settings (i ran the Level 2) or put it in stock mode for highway driving? Seems real bad on the highway. Any input would be appreciated.

 

You're getting the gas mileage I am, with "custom" tunes. I have an SCrew 4x4 with 3.73 gears and stock (32" tires). I also haul around a bed cap that probably weighs about 250-300#, and, generally don't drive the truck on the highway with fewer than 5 people and luggage/food/"stuff" aboard. My cruising speed is about 75 MPH.

Now, you've upped your tire size and lifted your truck. Both mods are probably going to hit your fuel economy. I don't know what model truck you have though - a 2WD 2-door is going to be more fuel efficient than mine.

Lifted truck, bigger tires = more wind resistance at cruising speed. If you have not regeared, the load on the engine is increased just to maintain that cruising speed, due to the reduced mechanical advantage, even though the RPMs are lower. You possibly COULD get better mileage by cruising in 3rd gear, rather than O/D, depending on your speed.

- Jack

 

Yeah mine is a crewcab 4x4 but that is me driving in 2wd. I'll try staying in 3rd I guess. O thought maybe I'd have to do something to the edge in the settings or something.

 

Please! Don't think I was suggesting you use 4WD on the hardball! It's just that a 4WD vehicle has a bit more loss in efficiency due to the more complicated drive train (even if it's not engaged).

You did not tell me your Gear Ratio. I suspect now, with your oversized feet, you are badly undergeared. As I said, this can seriously increase the load on the engine at cruising speed, even if the RPM stays lower. Do you notice a tendency for the Torque Converter to unlock and relock a lot?

And, you did not tell me your cruise speed. If you are driving at 75, like me, you are putting a very heavy load on the engine with those feet.

There's really not much you can do in the custom settings to offset the big wheels. That's already been done in the basic tune.

- Jack

 

Hey my usual cruising speed is about 70mph. What do you mean about the torque converter? Sorry don't know much about it. Also it's got the 3.73 gears in the truck. I figured it be bad on the highway, just that my city and highway gas milage are so close. Thanks for the replies by the way.

Dave

 

Dont touch a thing .... lol.

15.5 MPG with 35's is fantastic from what ive read.

Most are barely getting that with stock settings.

If i thought i would get your same mileage i would be buying 35's as well.
With fuel prices climbing, I'll stick with my stock tires awhile longer.

 

Sorry, if you want to play, you gotta pay.

 

Are these MPGs hand calculated or lie-o-meter?

 

Don't touch anything.....better than what I get for mpgs....but they still are selling winter blend gas here....

 

These are calculated.

 

Happy to give you opinions, Dave.

The Torque Converter is a fluid clutch that sits in front of the transmission and acts in two different ways. One, when you're at a standstill with the engine running and the transmission in gear, it "decouples" the engine from the transmission so that the engine won't stall.

But, when you operate the truck under load when you're moving, the selected gear on the transmission may be just a bit high for the power the engine can produce at that RPM. In this case, the Torque Converter unlocks to allow the engine to spin at a higher RPM, where it can produce more torque. That torque is transmitted through the fluid coupling giving you more torque on the drive axle. As such, the Torque Converter is a "torque multiplier".

A common symptom of operating the engine at too high a gear setting (in your case, 4th gear with a high load) is that the TC will repeatedly unlock and then lock up again. You would notice this as a constant fluctuation in your engine's RPMs. If that's happening a lot, it's a signal that you should probably lock out the overdrive to take the strain off things. Unfortunately, that's going to increase your RPMs to about 2575, which is probably higher than you really need or want.

I just did a rough calculation and I think that by running 35" tires with 3.73 gears, your effective gear ratio is only 3.41. That would put you at about 1800 RPM at 70 mph. The engine is operating down where it has very little torque reserve. You could probably regain the "OEM" feel by changing your axle gears to 4.10 (front and back). This would put you at close to 2000 RPMs at 70 mph in 4th.

However, I don't know that you would increase your gas mileage that much. I'm in agreement with the ones who've said you're doing great as is. You probably aren't hurt so much in city driving, because your speed is lower, which greatly reduces the engine load.

- Jack

 

I did a 220 mile each way highway trip a couple of months back.
Cruise control set on 70 mph.

Level 2 one way...14.25 mpg.

Level 1 coming back...15.35 mpg.

Figured using the fill up calculations.

 

Skiz - your MPGs look pretty normal, but I'll submit that other factors may have contributed to the mileage difference besides the tune change. Is is possible that the trip out was somewhat uphill and the trip back downhill? Is it possible the trip out was into a headwind, maybe a tailwind or no wind coming back?

Either of these two environmental factors have a STRONG influence on gas mileage.

In 1850 miles of highway driving on a single tune, I've seen a low mileage at fillup of 13.2 mpg and a high at fillup of 17.7. The average over the entire distance was 15.2. A previous record, over 5671 total miles was 15.1 mpg. So, I am pretty confident I get about 15.1-15.2 mpg on the highway, when all the environmental factors are averaged out.

- Jack

 

No doubt..Way too many variables to set any numbers in concrete after one test.

I'd like to do more MPG figures, but have a hard time not using the Edge for the reason I bought it.
And the reason wasn't to drive like an old lady. With the price of gas I try, but it's a losing battle.

 

It's funny, I probably drive like an "old lady" to most of you, but I'm kind of "fast" in my crowd. I don't feel any need to race anyone to the next stoplight, but when I want to pass someone on a two lane road or need to get up to speed to merge with freeway traffic, I'm happy to "punch it" and feel the power is there to get me where I want to be.

I know I'm driving a truck, not a rail, but I see the programmer as telling the truck to respond to MY commands, and not some other wimpy setup.

- Jack