First trip with the 3.0L Duramax

[BJ Niceguy]

i did a 750 mile trip yesterday from Omaha to Minneapolis and back in 2020 chevy 1500 with 3.0. All stock except have Michelin tires and box flat cover. Mix of interstate at 72, 4 lane at 67 and 2 lane at 60mph with very little wind. Averaged 32.4 MPG for entire trip and 36.3 for 50-miles best when on 2 lane part. Very happy. I bought fuel at half way point but could have made round trip on one tank. truck has 10.5k miles now.

[Duramax3oh]

On 7/30/2020 at 3:41 PM, BJ Niceguy said:

i did a 750 mile trip yesterday from Omaha to Minneapolis and back in 2020 chevy 1500 with 3.0. All stock except have Michelin tires and box flat cover. Mix of interstate at 72, 4 lane at 67 and 2 lane at 60mph with very little wind. Averaged 32.4 MPG for entire trip and 36.3 for 50-miles best when on 2 lane part. Very happy. I bought fuel at half way point but could have made round trip on one tank. truck has 10.5k miles now.

Which Michelins did you go with? Are they the Defender LTX M/S in stock size 275/60R20 by chance? Impressions on ride feel and mileage compared to stock? Thx

[BJ Niceguy]

that is tire I bought. Not sure if mileage got better, but not worse for sure. I feel the tires are way more stable when towing (less squirmy). Ride a little softer over bumps. Have 5K on them and happy with change.

[Duramax3oh]

This thread has some great discussion around MPG so I wanted to share my recent experience now that I've actually towed for the first time. This all takes place between Houston and Austin on 290 which is for all intents and purposes a pretty flat drive. There are some hilly sections but a very far cry from being in mountainous regions. This is stock Crew Cab Z71 with 3.0L, 3.23 axel ratio and the 275/60R20 Bridgestone Dueler A/T RHS at 36psi cold temp. Only additions to truck are spray-in bedliner, Bakflip fibermax bed cover, and AMP research power steps. Had Equalizer WD hitch in bed which weighs ~ 100lbs (edit: and wife in car... driver and passenger combined weight probably 280 lbs)

 

1) Regular driving mode, Unloaded drive Hou-ATX [one stop at Buc-cees (no gas) and a drive-thru for lunch]: 179.4 miles 26.3 mpg avg(per DIC), largely going 65-75 mph, max at 80 for brief period

2) Tow/Haul driving mode, Loaded with 23' 5,000 lb Airstream drive ATX-HOU [no stops]: 183.1 miles 15.9 mpg avg(per DIC), largely going 60-70 mph although I got up to high 70's without realizing it at all. You gotta watch this pup!

3) Total combined miles of 371.5 (includes unloaded + loaded drives + 9 miles from storage to home) - 17.867 gallon refuel = 20.79 combined mpg (slight decrease in avg from just averaging the above two figures bc truck was idling for a long period at the trailer dealer while doing walk-thru, setting up rear trailer camera, etc.)

 

This was my first experience towing anything. I will say the combination of this truck, the engine, transmission, and the weight distributing hitch far surpassed my expectations (maybe I tend to worry too much). I was extremely impressed with the overall handling and feel. Trailer tracked my truck like a shadow, did not feel any effects from semi's passing me by... it was a very easy tow.

 

 

TLDR: This truck is a little badass and I love it.

Edited August 5, 2020 by Duramax3oh

[Grey3liter4x4]

Picked the truck up from the dealer and on the return trip home 100 miles with 43 miles on the odometer.  Return trip home was over a 4500' narrow and winding road with a long straight flat section the last 40 miles.  Tried to keep the truck under 60 for the break in period averaged 33.2 mpg with a best of 34.8!  Truck is a crew cab short bed LT 4x4 Z71 3.23 gearing.    

[TNTSierra]

I just drove a 3.0L baby Duramax in a 2020 Denali on Monday at Billion Auto while my cousin was getting a 2018 GMC Duramax. It was very quiet when starting up and driving. The throttle response was very good for a diesel. Nothing like my 6.2L but very linear. The salesman said a guy in Oregon took one of these diesels, folded in the mirrors, kept speed at 60 mph and received over 40 mpgs in a test run of over 400 miles. Didn't care about how fast he was going and just drove it gently. Pretty impressive

 

I was impressed as well, but I just bought my 6.2L. I think if I would have driven this before my 6.2L I would have strongly considered just for the MPGs sake.  My new 6.2L hasn't gotten over 20 mpgs  yet.  My 2018 with a 8 spd and 6.2L got 23 to 24 mpgs all day long running 60 to 70 mph

[Duramax3oh]

About a 700 mile drive today on the way to CO thought I’d post some figures. Total weight of truck and trailer 11,980 lbs. The good bad and ugly. Higher speeds than last time lot of time in the 70’s. we stopped several times for bathroom breaks for the Mrs and the dogs:

 

1) 263 miles 13.5 mpg per DIC, 14.03 hand calc 

2) 187 miles 13.9 mpg per DIC, 14.88 hand calc

3) 172 miles 12.9 mpg per DIC, 13.72 hand calc

 

DEF started 1 bar from full (aka 1 bar used up). At stop 3 the low DEF alert was on red and I was close to empty. Filled up 4 gallons. Seems like I sucked a ton of DEF for only 622 miles no? Trailers gotta be sub-5500 lbs right now. 

[Paul ONeal]

Hi all, have a 2020 GMC Sierra SLT 3.0 with the stock goodyear tires.  I have added the gmc floor liners , bedrug , and gator bed cover.  I live in NC, was able to get 26.5 mpg on a 240 mile relatively flat highway trip to the coast doing the 65-70 mph speed limit.  I've made that trip a few times this summer.  Now, I just did a 230 mile trip from Greensboro to Sevierville TN near Gatlinburg through the mountains.  Very dynamic road conditions, some 6-8 degree inclines and twisting roads.  I was towing a 2010 Jayco x23b camper, about 4900 lbs dry, maybe a couple hundred pounds gear in the camper and other couple hundred in the truck bed. 2 adults.  I averaged 13.6 mpg up the hill and 14.4 back down.  The trip was made speed limit or below.  I saw another poster did a little better towing an airstream.  The airstream is definitely more aerodynamic. 

[Duramax3oh]

Stupid awesome. Pulling the trailer from Houston to New Orleans yesterday, roughly 350 miles on a single tank of gas. Stayed on cruise control at 65 mostly some at 70 and some at 60 to get a feel for “slower” mileage. Also ran into bad stop and go traffic twice. 
 

Overall trip DIC showed 16.5 MPG and hand calculated got 16.95, thrilled with 60 MPH cruise control DIC showing 19.7 MPG for over 25+ miles!

Edited September 3, 2020 by Duramax3oh

[Ojustracing]

Just covered 3100+ miles for a  calculated average 35.01Mpg.  Current tank is on par to increase that number by a bunch.  At 700 miles the DTE still reads 217 miles to go.  Which would put the overall tank at 917 miles !!!!