Made a change in my fleet..

[Smokescreen]

Our family dynamic is changing and even though it still has plenty of life left in it, the Burb was needed elsewhere in the extended family with someone who hates minivans.

So this month I sold the 'Burb and bought a 2003 GMC Sierra 2500 6.0L Vortec. There is quite a bit more power, torque and utility with this new truck, which should fit our needs. I was however able to prove once again (as with all my vehicles) that I have the ability to obtain higher fuel economy than EPA suggests. In fact so far it may has better fuel economy than the suburban did which is great for me. I haven't had a chance to change up the fluids etc, but from what I read, the near bullet-proof engine and transmission won't be fussy, as this is a vehicle meant to do much more work than I will put to it...but that's ok as it is will be used less frequently.

 

[mcrn]

Congratulations.

 

[dave123]

And what might this killer fuel economy be my wifes 2012 2500HD 6.0 pulls a solid 13mpg with mixed driving.

 

[Smokescreen]

Solid highway driving, 50F (10C) in the rain at 55mph (90kph) 19.43 mpgUS (12.1L/100km) according to the dash gauge. I do have a topper on the back.

I plan to move to skinnier 235/85R16 tires at 40psi, give the truck the once over for fluids and do a screen upper grill block maybe even a lower chin air dam, so I can get even better.

 

[dave123]

Yea right

 

[NHGUY]

So a 5.3 would probably get 22-23.

 

[Smokescreen]

I have meticulous spreadsheets documenting my mileage. Once I get a few more fill-ups and develop some better average I will post up. If you don't believe my numbers I can't help that.

My last 5 fill-ups in the Corolla have been 43mpgUS+ my running average is much higher than EPA...The LeSabre is also well above EPA. It's all about driving style.

 

[Clevy]

I've got a c3 and I can't break 16mpg on the highway with it. It's got a 6.0 but I think the c3 has a bit more power vs a standard 6.0.
My 99 with a 5.3 won't get better than 14mpg,so my 6.0 beats it there.

 

[Nick1994]

You can only go so far with the gas mileage in a big truck. I wouldn't trust the 11 year old on dash computer for mpg. Fill it up and do it the old fashioned way.

 

[hattaresguy]

6L's in 3/4 or 1 ton chassis are 10-14 mpg trucks.

The only ones that get 19 are the 14's with AFM.

 

[NMBurb02]

I believe his numbers. I got near 16.5 MPG (hand calculated) with my loaded down '02 Burb 4WD with the 5.3L on a 3,000 mile road trip with highway speeds mostly 70-80 mph, strong crosswinds much of the time, and crossing the continental divide twice (the climb up the Rockies leaving Denver is much steeper than the downgrade, so I wasn't able to do much high MPG coasting coming down the western side to regain lost efficiency during the climb).

 

[Jarlaxle]

Originally Posted By: NHGUY
So a 5.3 would probably get 22-23.


My brother's gets 16 on a good day. Average is 13-14. Best ever (all highway, empty, ~60 degrees) was a hair over 17.

 

[geeman789]

Originally Posted By: Nick1994
You can only go so far with the gas mileage in a big truck. I wouldn't trust the 11 year old on dash computer for mpg. Fill it up and do it the old fashioned way.


Indeed...

My fuel economy computer shows a consistent, and respectable, 8 liters per 100 km , not bad for a firmly driven all wheel drive car...

RIGHT. When I fill up to the 2nd click, drive, then fill up and actually calculate the fuel economy, my numbers are, ummm, SLIGHTLY! different.

Real world numbers are more like 10 to 11 liters per 100 km... ok , but not great. The computer is a little optimistic...!

As a Canadian of a certain age, I have never bought a gallon of gas, nor driven a mile...

A little math...

1 Us gallon = 3.78 liters
100 kms = 62 miles

So... 29 mpg indicated vs 21 - 23 mpg actual... not even close!

And I like the metric calculation better, gasp...

How much GAS do you actually use, where less gas used is better...

My dad still converts everything back to MPG, even though gas is sold by the liter, odometer is in kilometers and all speed limits are in kilometers per hour... for the last 30 + years. Old dogs, I guess.

 

[hattaresguy]

Originally Posted By: NMBurb02
I believe his numbers. I got near 16.5 MPG (hand calculated) with my loaded down '02 Burb 4WD with the 5.3L on a 3,000 mile road trip with highway speeds mostly 70-80 mph, strong crosswinds much of the time, and crossing the continental divide twice (the climb up the Rockies leaving Denver is much steeper than the downgrade, so I wasn't able to do much high MPG coasting coming down the western side to regain lost efficiency during the climb).


Their is a world of difference in weight and MPG between a half ton with a 5.3 and a 3/4 ton with a 6L.

What gears the truck has matters a lot as well, 4.10's are MPG killers.

 

[SteveSRT8]

Originally Posted By: Smokescreen
I have meticulous spreadsheets documenting my mileage. Once I get a few more fill-ups and develop some better average I will post up. If you don't believe my numbers I can't help that.

My last 5 fill-ups in the Corolla have been 43mpgUS+ my running average is much higher than EPA...The LeSabre is also well above EPA. It's all about driving style.


Since our newest fleet van can easily achieve 16-17 mpg on the highway at over 9000 pounds I believe him. The 6.0 has effortless torque and can be very easy on fuel...

 

[Hokiefyd]

MPG numbers are extremely variable and depend on too many things to mention. YOU might not be able to achieve a certain number where YOU live, and with YOUR driving style, and with YOUR climate and with YOUR roads, etc. But he might. I'm sure he has no reason to come to BITOG and lie about his mileage. What would help, however, is for the OP to include with this mileage his average speed. This may or may not be time consuming to figure. Essentially, how many miles did you drive on that tank and how many hours was your engine on?

I found that moving from a small town in western Virginia to a larger town in southern North Carolina had a DRAMATIC effect on our cars' fuel economy. I measured a 30-50% difference in the SAME VEHICLES. Factors:

- terrain here is relatively flat
- roads are straighter and wider and faster; average speed limit in Blacksburg is 25 mph with lots of stop signs, while average speed limit in Fayetteville is 45 mph with well-timed signal lights
- climate is warmer in the winter, which helps MPG, and hotter in the summer, which hurts MPG (more A/C load)

The reason I mention average speed is because it's deceptive. Even with the freer-flowing roads around here, my average speed is usually about 25 mph. Our old Cadillac had a readout that showed it. Smokescreen's truck may give him that figure, as well. So even though our roads are 45 mph and 55 mph, the time I spend idling at signal lights counts, too. All that added in, my average speed is 25 mph. That's a critical "equalizer" in the discussion of MPG. Someone living with a lot more traffic probably has an average speed of 10-15 mph.

Smokescreen lives in Alberta, Canada, and was talking about a 50 deg F drive. His A/C use is probably minimal, which automatically gets him a 15%+ gain on me right from the beginning. Alberta is probably thinly-populated compared with southern North Carolina, so I bet his average speed is much higher than mine. Could I get 20 mpg in a 2500 with a 6.0L V-8 in Fayetteville, NC, with the A/C cranked? Probably not. There's no way I'd be able to do it in hilly western Virginia. Could I do it up in Canada? Maybe.

 

[Jarlaxle]

Originally Posted By: SteveSRT8
Originally Posted By: Smokescreen
I have meticulous spreadsheets documenting my mileage. Once I get a few more fill-ups and develop some better average I will post up. If you don't believe my numbers I can't help that.

My last 5 fill-ups in the Corolla have been 43mpgUS+ my running average is much higher than EPA...The LeSabre is also well above EPA. It's all about driving style.


Since our newest fleet van can easily achieve 16-17 mpg on the highway at over 9000 pounds I believe him. The 6.0 has effortless torque and can be very easy on fuel...


You have the new 6L90 transmission. He has the old 4L80E. No comparison!

 

[glock19]

Originally Posted By: Hokiefyd

- roads are straighter and wider and faster; average speed limit in Blacksburg is 25 mph with lots of stop signs, while average speed limit in Fayetteville is 45 mph with well-timed signal lights


No kidding, it's really 25mph EVERYWHERE. I love going back to visit but I hate driving in Blacksburg.

 

[Bladecutter]

Originally Posted By: Smokescreen
Solid highway driving, 50F (10C) in the rain at 55mph (90kph) 19.43 mpgUS (12.1L/100km) according to the dash gauge.


Since the speed was a constant 55 mph for the trip, yes, I can believe your gas mileage in this big truck.

BC.

 

[Clevy]

I've no doubt that his mileage is as reported. At 55mph the engine is barely turning 1500rpm,and I think its pretty flat where he's at.