Got up to 39.7 MPG on highway from Laughlin, NV to Los Angeles, CA...296.4 miles driving straight...

waltchan · October 1, 2018

I was able to achieve up to 39.7 MPG maximum on highway straight for 296.4 miles driving, no restroom break, from Laughlin, NV to Los Angeles, CA. I arrived home with at least 3/4 gas tank left ($2.43 per gallon price was too precious from Bullhead City, AZ).

Can anyone achieve this MPG number, or am I just too lucky? Is my MPG way too high and making people jealous? It wasn't difficult at all, but required patience and dedication. More details later...

https://plus.google.com/photos/photo/118325946855725849928/6607283031937325170

Model: 2018 Chevrolet Silverado 1500

Trim: LT

Cab Style: Regular

Engine: 4.3L V6

Transmission: 6-Speed Automatic

Drivetrain: 4X2

Axle Ratio: 3.25

Box: 8" Long-Bed

Fuel Tank: 34 Gallon

Odometer: 1,802 miles

MN1(SW) · October 1, 2018

Was it downhill the whole way? And how did you maintain that once you hit California traffic?

swathdiver · October 1, 2018

Coasting down the hills and mountains is always good for mileage and can often offset the climb. Now let us know how she does on the return leg.

Centex14 · October 1, 2018

558’ elevation to 258’ elevation so technically yes, down hill all the way.

2014 z71 LTZ
Volant Intake
Borla Exhaust
Diablo
Bilstein 5100
Rough Country Level

KJS Sullivan · October 1, 2018

"I arrived home with at least 3/4 gas tank left." And of course a full bladder LOL when I travel from Colorado to Kansas City I am dropping about 4000 feet and I get about four and a half more miles per gallon going east then I do West. That's the best I can offer :-)

Grumpy Bear · October 1, 2018

And the hand calculated number was what again? Your going to find that your multiple tank hand calculated average runs 8-10% less. That is still an impressive number and given the trip length and possible conditions I could get my head around the actual number. (36.5 tops) I did the entire month of September to the hand calculated tune of 30.5 mpg over 3695 miles in northern Illinois. Shorter bed, same motor/trans.

waltchan · October 1, 2018

9 hours ago, MN1(SW) said:

Was it downhill the whole way? And how did you maintain that once you hit California traffic?

Some uphill, of course, which dropped MPG quite a bit as low as 23 MPG. I drove up to 42 mph max speed at 1,000 RPM exact on truck slow lane while going uphill mountain terrain only, which is the 6th gear minimum overdrive speed requirement for the 6-speed transmission GM trucks. When coasting down, I shifted to neutral, up to 82 mph speed max.

Grumpy Bear · October 1, 2018

3 hours ago, waltchan said:

Some uphill, of course, which dropped MPG quite a bit as low as 23 MPG. I drove up to 42 mph max speed at 1,000 RPM exact on truck slow lane while going uphill mountain terrain only, which is the 6th gear minimum overdrive speed requirement for the 6-speed transmission GM trucks. When coasting down, I shifted to neutral, up to 82 mph speed max.

Okay a true hypermiler. That changes things.

Superman_006 · October 1, 2018

I realize the theory on "natural going downhill" but I thought all of the engineers have agreed that your engine idling takes more than the transmission being engaged and keeping the engine turning. If not I would think every car/truck would be like the old ford probe and have a 1-way bearing at the torque converter. Also cant you hold the tow/haul button down for a few seconds for it to automatically dis-engage the torque convertor clutch so you can coast down hill?

Rolling Thunder · October 2, 2018

17 hours ago, waltchan said:

I was able to achieve up to 39.7 MPG maximum on highway straight for 296.4 miles driving, no restroom break, from Laughlin, NV to Los Angeles, CA. I arrived home with at least 3/4 gas tank left ($2.43 per gallon price was too precious from Bullhead City, AZ).

Can anyone achieve this MPG number, or am I just too lucky? Is my MPG way too high and making people jealous? It wasn't difficult at all, but required patience and dedication. More details later...

https://plus.google.com/photos/photo/118325946855725849928/6607283031937325170

Model: 2018 Chevrolet Silverado 1500

Trim: LT

Cab Style: Regular

Engine: 4.3L V6

Transmission: 6-Speed Automatic

Drivetrain: 4X2

Axle Ratio: 3.25

Box: 8" Long-Bed

Fuel Tank: 34 Gallon

Odometer: 1,802 miles

Your DIC needs a service appointment.

j-ten-ner · October 2, 2018

8 hours ago, waltchan said:

...When coasting down, I shifted to neutral, up to 82 mph speed max.

You could have saved more fuel by staying in "D".

At 82 mph the fuel shut-off will kick in and give you more mileage.

so long

j-ten-ner

Artie61 · October 2, 2018

When you fill up does your DIC say 1300 miles to empty ? ,That would be pretty cool to get a picture of that on next fill up!

waltchan · October 2, 2018

5 hours ago, Artie61 said:

When you fill up does your DIC say 1300 miles to empty ? ,That would be pretty cool to get a picture of that on next fill up!

DIC says 915 miles left to empty, despite 315 miles already driven so far in one tank. So, that's 1,230 miles per tank for 32-33 gallon (maybe 1-2 gallon not counted and reserved for super low-fuel mark)

Nick The Great · October 2, 2018

Awesome. My first truck had the 4.3 in it, and it was very good on fuel. I'd get over 20 in fair driving conditions. And high teens in bad conditions.

L86 All Terrain · October 2, 2018

I highly doubt it. Most 4 cylinder cars can't even realistically achieve that in real world situations. DIC is usually about 10-20% under actually economy I have found with late model GM's. Even at that your still seems high. Tail wind, no ac, rcsb, v6 2wd, on a 2% slope with the body gaps taped off sitting 5 feet behind a transport truck, then maybe.