Hand Calculated Fuel Mileage?

[Rc51con]

Friends!

I have a 21’. I am getting ready to buy tuning from the Dr.

What HONEST hand-calculated fuel mileage are some of you getting with your trucks on 35s?

The current tuner I’ve been using has been very acceptable; yes, I know; buy a Prius if you want fuel mileage, whatever.

But I’ve seen some guys getting 19-22 hand calculated, and I’m getting 14.

With as much as I drive, it could be 1500$ a year in savings (or to buy other junk/goodies, haha)

Appreciate you taking the time to look at my post.

God bless.

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[AK Bob]

Fuel mileage will vary widely with the truck, tune, and driver.

At best, I wouldn’t expect to see more than a 1 to 2 mpg increase.

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[Corkey]

I did a 400 to 500-mile run down south when I still had 35s and got 21 to 22 with a 3.73 ratio.

As Bob said, Mileage is a gamble from so many variables.

You get what you get.

If you average lower than expected, buff the rig more often to compensate.

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[Rc51con]

I did a 400 to 500-mile run down south when I still had 35s and got 21 to 22 with a 3.73 ratio.

As Bob said, Mileage is a gamble from so many variables.

You get what you get.

If you average lower than expected, buff the rig more often to compensate.

That’s the thing, though, LOL.

There isn’t that big of a variable.

You had a 21 on 35s with the same gearing as I did and got EIGHT MPG’s better than I did.

I never go over 74 mph.

And dudes are getting 20 doing 80-82, haha.

What on earth is wrong with my truck?

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[Corkey]

That’s the thing, though, LOL.

There isn’t that big of a variable.

You had a 21 on 35s with the same gearing as I did and got EIGHT MPG’s better than I did.

I never go over 74 mph.

And dudes are getting 20 doing 80-82, haha.

I have a 2008 that got 21 to 22 mpg on that run.

All around tire dimensions, gear size, injectors, CP3 pump, throttle position, grades on hills, elevation, lifted vs. stock height.

Not every truck with custom tuning will achieve identical results via power and mpg.

Somewhere on here, DRD has been asked this same question numerous times.

What I got from it is just to be happy with the motor being able to breathe and work properly.

Adding fuel additives help a lot.

I run every other tank with Lucas's upper cylinder cleaner.

I know fuel components are spendy, so I get a big bottle of that to prolong internals, not to mention you gain MPG with the stuff.

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[Murph]

Well Sir, may I add some subjectivity here, LOL.

As to some intel being given or found by your searching and responses are already given here by staff, very subjective.

Here's my inference.

I go back and forth to (5600 ft elevation) Wyo from southern AZ 2750 ft elevation.

Some interstate, mixed with two-lane highways, not towing and can make the climb, more LOL, right at two tanks of fuel.

Reverse, and I make it down the hill on a tank and a half.

I did ONCE just for S&Gs on the way down the hill, maintaining no more than 55 with no interstate.

At the midpoint, after filling up (30 gallons- hand cal'cd just south of 25mpg), the lie o'meter on big red showed me the elusive 705 DTE!!!

Painful, yes, that drive was, LOL.

I run on cooper 315's matched tire pressure when not towing and usually no faster than 75.

So as not to raise anybody's ire here, but when fuel mileage comes up, some people will give you their best scenario short-term downhill, I suppose, snapshot, for instance.

So who knows, always a good chat, and still I marvel that at even 15mpg, moving 7-8K worth of truck is impressive!!!

So go forth, young man and let your experiment continue; I did enjoy the Prius retort!!

More LOL!

I hear that all the time from owners who are eavesdropping and offering the depth of their intelligence to our simply passing the time with coffee and fellow enthusiasts talking shop!!

Have a great W/E y'all.

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[SSLandYacht]

Mixed town and freeway 16, all freeway on boxed 150 tune about 22 if you keep it around 70 75.

If I do 65 with 3.42s, it's like 18. 3.42 gears are great for stock tires 35"s not so much LOL average between 400-500 miles to tank depending on driving.

Now, if a flat road cruise is set at 60, I think I could go 600 miles on one tank.

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[DIESELWRKS]

My best mpg 19-20 comes from driving just under 1500 RPMS.

Speed is roughly 66 to 68.

I use the cruise control.

This is 500 to 800 elevations.

If I go over 70, it will drop.

I have 3.42 gears and worn tires that are closer to 34.5.

I only accelerate if I need to.

Just easy.

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[BrentM]

I have been tracking my fuel use and mileage from the day my 2017 was new.

On the factory wheels and tires, I was getting 15.7 MPG over 4,000 miles. A

fter the modifications, including 38" tires, I have gotten 15.3 MPG over 42,000 miles.

I have 4.56 gears sitting in my garage to replace the 3.42 factory gears, not sure what that will do but I am thinking it will get me back to 15.7, but that is not why I am doing it.

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