Gas Mileage on 5.3 V8 engine on a 4x4

aseibel · March 20, 2019

There is an automatic grade braking function that you can manually disable by pressing the tow/haul button for 5 seconds. At lease on my 2015, not sure if its the same on 2019.

My computer calculates very close, usually .5 mpg or less higher than hand calc mileage. The more time spent on the highway, the closer it is.

Wiggums · March 20, 2019

I know I can manually disable it by changing it to "L" and selecting 8. That's what I've been doing if I want to stay in the top gear going downhill.

If you do the tow/haul, does it downshift going down hill? On the Ford, it downshifts more aggressively without braking.

I see your version is pre-2018, owners of 2019 models say it's spot on. I am curious to see that with the first fuel tank. My Ford was way off though so i just subtract 10%.

Smitty · March 20, 2019

I've only taken my 2019 6.2 on one semi long trip and I was getting 25.8. Around town I can get 18 if I drive it carefully but that's no fun. I think you could get 28-30 pretty easily on a long trip if you keep your foot out of it. This thing is really impressive on MPG.

Smitty

Nanotech Environmental · March 21, 2019

I know that my '17 is capable of getting pretty decent mileage. It's just hard to get it often due to heavy traffic, weather, construction, etc. where I live.
My best so far is 8.3liters per 100km, over a 100km stretch, which works out to about ~27.5 mpg US. On long highway trips, where I can take it easy and not have stupid traffic etc., I can usually avg about 23-24mpg US over a whole tank.
My DIC is a bit optimistic, but still pretty close to manual calcs.

I have a 5.3, 3.42 4x4 dbl cab 1500 with a tonneau cover.

Waaay better in every way than the old 84 fullsize 4x4 I had years ago. lol

reardiff · March 21, 2019

3 hours ago, Smitty said:

I've only taken my 2019 6.2 on one semi long trip and I was getting 25.8. Around town I can get 18 if I drive it carefully but that's no fun. I think you could get 28-30 pretty easily on a long trip if you keep your foot out of it. This thing is really impressive on MPG.

Smitty

I realize this a 2019 forum but for what it's worth, I recently went from Chicago to Denver and back and averaged 24.2 in my 2017 6.2. Should have taken a picture of the DIC. This was at 70 mph just about the whole way. So mid 20's is very doable on an extended highway trip. I'd imagine a 5.3 would may even be a mpg or two better than that

KozzyJr · March 21, 2019

1 hour ago, Nanotech Environmental said:

I know that my '17 is capable of getting pretty decent mileage. It's just hard to get it often due to heavy traffic, weather, construction, etc. where I live.
My best so far is 8.3liters per 100km, over a 100km stretch, which works out to about ~27.5 mpg US. On long highway trips, where I can take it easy and not have stupid traffic etc., I can usually avg about 23-24mpg US over a whole tank.
My DIC is a bit optimistic, but still pretty close to manual calcs.

I have a 5.3, 3.42 4x4 dbl cab 1500 with a tonneau cover.

Waaay better in every way than the old 84 fullsize 4x4 I had years ago. lol

I saw the exact same mileage in my 2017 6.2 Denali. Mind you I was driving the speed limit of 90km for roughy 75 km. These trucks can get good mileage if you keep your right foot out of it. Best I’ve seen so far on my new at4 is 9.7.

Cpl_Punishment · March 21, 2019

If I remember correctly, Mythbusters got the best fuel economy with a piece of plastic "netting" in place of the tailgate because you lose the weight of the tailgate but you maintain the aerodynamic benefits of having it there.

Wiggums · March 21, 2019

I don't remember how heavy the tonneau cover was in that show but it fared worse than having the tailgate up. Having the tailgate down also got worse gas mileage than tailgate up. I do recall plastic netting yielding the best gas mileage too.

aseibel · March 21, 2019

14 hours ago, Wiggums said:

I know I can manually disable it by changing it to "L" and selecting 8. That's what I've been doing if I want to stay in the top gear going downhill.

If you do the tow/haul, does it downshift going down hill? On the Ford, it downshifts more aggressively without braking.

I don't know what you are asking here. In WI we don't have too many hills big enough to require brakes when going down. But there is a nice smooth stretch where the speed limit goes down from 55 to 35, where I always let it coast for a while. I notice a considerable improvement in coasting distance when I disable the grade braking first. I don't think there is any downshifting involved with/without it in my truck.

You should try it and see what your truck does.

BigBadSierra · March 21, 2019

I have had three and they all life time averaged at or around 18mpg We have mandated ethanol in all but some 91, and 93-94 octane gas has none.

I can get higher millage on US gas. I dove the last truck form southern Ontario to central Florida on two tanks.

The only difference is the 2018 Is most likely going to average 18.5 or 19 those silly active shutters are actually making a difference.

Primarily on the -22 Degree Celsius days as the this tuck doesn't drop to 13 or 14 mpg in the cold like the 2014 and 2016 did so the only difference is the shutters keeping the engine warmer.

As there is no way closing them and making the grill into a cup would help the millage. But the scan tool is showing the engine sitting at steady temp in this truck. My non shuttered trucks struggled in the cold to stay consistent.

Sierra Dan · March 21, 2019

Gear Ratio plays a big part in MPG.

This will have an impact on overall mileage by at least a couple average.

Wiggums · March 21, 2019

1 hour ago, aseibel said:

I don't know what you are asking here. In WI we don't have too many hills big enough to require brakes when going down. But there is a nice smooth stretch where the speed limit goes down from 55 to 35, where I always let it coast for a while. I notice a considerable improvement in coasting distance when I disable the grade braking first. I don't think there is any downshifting involved with/without it in my truck.

You should try it and see what your truck does.

Here, it's really steep downhill and limit drops from 45 to 35 and there is almost always a motorcycle cop. I still don't want it to brake, i want to control it myself.

I just want it to prefer downshifting rather than braking while it's slowing down. If it won't downshift then I'll do it. I want to maximize the brake life.

Controller23 · March 21, 2019

This guy.. so full of shit

Sent from my iPhone using Tapatalk

aseibel · March 21, 2019

10 minutes ago, Wiggums said:

Here, it's really steep downhill and limit drops from 45 to 35 and there is almost always a motorcycle cop. I still don't want it to brake, i want to control it myself.

I just want it to prefer downshifting rather than braking while it's slowing down. If it won't downshift then I'll do it. I want to maximize the brake life.

Ok, I get it.

"grade braking" does not use the brakes at all. It uses the engine compression and transmission resistance to slow you down. I haven't noticed it downshift to accomplish this, but I imagine it would if your speed allowed for it.

Turning this off just allows you to free-wheel down grades more.

Wiggums · March 21, 2019

The reason I mentioned gas mileage is because I had a bigger gas tank in my other truck but worse gas mileage. Still, I could get around 700 miles on a 36-gallon tank.

Once in a while, I drive from Tijuana to Hermosillo. It's a 500-mile trip one-way and I don't like getting out of my car in the area between the two so I drive only cars that can comfortably do 500 miles without needing a refill.

The new Silverado has a 24-gallon tank but quite a bit better gas mileage, I think it's only 80 miles less on a single tank despite the tank being 12 gallons smaller.

Although the highway is posted at 110 km/h most of the way, the jarring speed bumps really get to me so I drive around 80 km/h which greatly helps the gas mileage.