Boss gas milage info

[Jmzvet]

If you can find the “sweatspot” where it can operate at the lowest rpm in 4cyl mode and still maintain a decent speed for several miles, there’s no doubt you can easily get over 25mpg

 

[Keller]

5.3, 10 speed, DFM disabled.
15.5 MPG - 90% highway driving.

 

[timebak]

I'm looking at a 2020 Boss 5.3 with a 6 speed.
I see they have 8 and 10 speeds also.
What's your gas milage guys with different engine/trans set ups.
4 cyl, v6,5.3 and 6.2

2021 6.2 w/10-speed: I can get 21-22mpg rolling 50 mile average piddling along at 50 to 65 if I keep my foot out of it. Normal mixed driving around on farm, some in Auto 4wd, short trips (~13 miles to town plus 5 to 10 in town, and back out to farm) I get around 14 to 17 mpg, depending on how much I enjoy the 6.2's performance. Towing my travel trailer (about 5400 lbs) at highway speeds, I'll get 10 to 14 mpg, depending on the amount of hills and mountains. A few times I've had to tow a trailer with farm equipment aboard (10,000 to 17,000 lbs), and the Trail Boss and the 6.2L start to realize that something's back there. The mileage can drop below 10 mpg, even though I limit speed to 45 to 55 mph, depending on the load. I know that that is technically above its rated towing capacity, but I take it easy, accelerate slowly, the trailer is carefully balanced and has excellent brakes, and the distance is never more than 20 miles, usually 9 to 10 miles on quite flat roads.

 

[Coachsimmons85]

first 2 weeks with the 23 3.0- 110 miles back and forth to work each day... 29 mpg- almost 700 miles between fill ups...
love this truck

 

[clstark7]

If all I'm doing is running the kids to/from School or Grandma's during the week, this is about what I get.

If a mix of highway/city, I'm closer to 19 MPG.

If just a highway trip, cruise set at 65MPH then I'll get about 21-24 MPG.



Only when on flat land, long highway trip, little to no wind, or a tail wind, then I can get 25-26 MPG.

Between the intake/filter, oil catch can, exhaust, and using 93oct, it helps quite a bit.

My wife already ordered me a Stillen ram air scoop (my Christmas present - it was 20% off over at Stillen w/ BF20 code), and I'm looking at a crank underdrive pulley, just not sure which I want. Most of these mods just 'free up' robbed HP/TQ, and in the process, less effort is needed for acceleration, or to keep highway momentum, especially when DFM kicks in, and it cylinder cuts, it's less stress/strain on the 4 cylinders that are operating, and stays in DFM mode longer. It also causes a gurgling exhaust note, which is kind of cool.

If you have the LT Trail Boss, make sure to shave off about a quarter of an inch from the front of that Stillen cold air scoop where it scoops the air, or it will catch on those aero shutters (or whatever they are called) just behind the grille when they try to open or close. I had to do that with mine. When it catches, it sounds like bad lifters lol.

 

[Shaun808]

I have a 2020 TB 5.3 stock engine, only mod I have is an oil catch can. I live in Hawaii and I’ll get 16.7-17 mpg

Anyone have any tips, to get that number higher???

 

[HopnDude]

I have a 2020 TB 5.3 stock engine, only mod I have is an oil catch can. I live in Hawaii and I’ll get 16.7-17 mpg

Anyone have any tips, to get that number higher???

K&N 57 series intake & filter using stock air box. Maybe even the Stiller cold air scoop. The lower the IAT's, the better the timing. The better the timing, the better the detonation. (domino effect) Exhaust wise, depends. But making sure to remove any/all slow downs to air entering the engine would allow it work more freely.

There are also two Crank Underdrive pulley options. Not sure if ATI's is finished yet, but some other company has one.
ATI - 10% smaller
UPD - 23% smaller

 

[Shaun808]

K&N 57 series intake & filter using stock air box. Maybe even the Stiller cold air scoop. The lower the IAT's, the better the timing. The better the timing, the better the detonation. (domino effect) Exhaust wise, depends. But making sure to remove any/all slow downs to air entering the engine would allow it work more freely.

There are also two Crank Underdrive pulley options. Not sure if ATI's is finished yet, but some other company has one.
ATI - 10% smaller
UPD - 23% smaller

Do you think by using non ethanol gas would help also? I’ve been using Shell premium plus, but I’m thinking about using ethanol free gas instead.
Also would using a fuel injector cleaner work?

 

[HopnDude]

Do you think by using non ethanol gas would help also? I’ve been using Shell premium plus, but I’m thinking about using ethanol free gas instead.
Also would using a fuel injector cleaner work?

Do you mean gas w/o the 10% +/- E content? Not sure it'll make a huge difference.

I started using only Premium, but I don't drive much. I'm permanent WFH.

Injector Cleaner won't do much, unless you use dirty fuel and your injectors are possibly clogged. It's Direct Injection, so it's not like running a solvent over the intake valve helps clean them for better air/fuel mix/flow. The Oil Catch Can helps catch mixed unburnt fuel from being pulled back through and sludging up the intake ports and valves. Maybe once every 10k, run a decent cleaner, but that's all I'd suggest.

You have DFM/AFM active? What transmission do you have?!

 

[Shaun808]

Do you mean gas w/o the 10% +/- E content? Not sure it'll make a huge difference.

I started using only Premium, but I don't drive much. I'm permanent WFH.

Injector Cleaner won't do much, unless you use dirty fuel and your injectors are possibly clogged. It's Direct Injection, so it's not like running a solvent over the intake valve helps clean them for better air/fuel mix/flow. The Oil Catch Can helps catch mixed unburnt fuel from being pulled back through and sludging up the intake ports and valves. Maybe once every 10k, run a decent cleaner, but that's all I'd suggest.

You have DFM/AFM active? What transmission do you have?!

It’s the DFM and 8 speed trans

 

[Perry]

If you have the LT Trail Boss, make sure to shave off about a quarter of an inch from the front of that Stillen cold air scoop where it scoops the air, or it will catch on those aero shutters (or whatever they are called) just behind the grille when they try to open or close. I had to do that with mine. When it catches, it sounds like bad lifters lol.

Stillen modified their design to accommodate for the aero shutters. It is even noted on their website (*NOTE: As of February 15, 2022 this product is compatible with the active aero shutters.). I bought one this past August for my 22+ LT TB and no issues with interference.

 

[HopnDude]

It’s the DFM and 8 speed trans

Would have to get a larger pool of both 8spd and 10spd 5.3 owners to know if much of a difference, but if there is it would be small.

How much time do you highway drive vs city drive?

 

[bossboy302]

New 50 mile best=38.2 mpg. No load, no tailwind.
I have noticed the engine (Dmax) is running quieter(?) and more smoothly. An OTA adjustment? 'Learning'? (2k miles-slow learner).
The low speed shifting has also smoothed out.

 

[Jmzvet]

About how many RPM is the dmax turning at 65mph on flat ground?

 

[Coachsimmons85]

about 1300