M P G in suburban

7echo

Adventurer
What sort of set up gets the best MPG in a 2500 Suburban with an auto trans?


I am interested in a mid to late 90s model. Though I like the '91 and earlier body style I doubt I could find one in good daily driver shape.
 

Kaisen

Explorer
You had the choice of three engines:

5.7L Vortec V8 - expect 12ish around town, and 15ish freeway

7.4L Vortec V8 - expect 10ish around town, and 13ish freeway

6.5L Turbodiesel - expect 14ish around town, and 19ish freeway

Tires and gears will make some difference +/-
 

cdthiker

Meandering Idaho
Do burban and MPG even go in the same sentence ? hahaha
We ran a few as work transport rigs and they did ok. Mind you this was out in middle of nowhere UT and they were always freighted and full of crap. This max paylaod and then perhaps some.
we got low teens running around and even lower when off road and that was all the time... single digits were common for combined driving.

Despite the fact that they were always breaking down. I was always impressed with how much junk ( like a thousand poounds of water and then a bunch of gear ) these things could move off road while still doing really decent in some nasty trails.

They ended up getting replaced with crew cab tundras but the burbans were like riding through the desert on a sofa. Cool rigs. Crap MPG and relibality. Of course if it was a personal rig vs a company one I am sure they could have done better in the long run.
 

Kaisen

Explorer
I've had several Suburbans and zero issues with reliability. My current rig has 260K miles on the original engine, transmission, transfer case, axles, alternator, starter, etc, etc. Two of my power windows are giving me issues, as is the power lock solenoid for my rear liftgate.
 

TxFarmTruck

Powerstrokin'
Never had reliability problems on a Suburban, but always kept up with preventative maintenance. Those things are some of the most comfortable road warriors out there, hands down. However, breaking 15 mpg loaded with the 5.7 is tough to do. 3.73s and 235/85s will help the mileage regardless of your engine choice. The 6.5 diesels actually do pretty well on mileage if you can deal with the motor itself.
 

chad6000

New member
Never had reliability problems on a Suburban, but always kept up with preventative maintenance. Those things are some of the most comfortable road warriors out there, hands down. However, breaking 15 mpg loaded with the 5.7 is tough to do. 3.73s and 235/85s will help the mileage regardless of your engine choice. The 6.5 diesels actually do pretty well on mileage if you can deal with the motor itself.

Tx, what do you mean, "deal with the motor"? Like repairs? Tuning?

(I might be missing it if the answer is obvious)


Sent from my iPad using Tapatalk
 

Kaisen

Explorer
Tx, what do you mean, "deal with the motor"? Like repairs? Tuning?

(I might be missing it if the answer is obvious)

The 6.2 and later 6.5 turbo diesels weren't medium-duty diesels like the Cummins, and they suffered numerous maladies. They weren't known for their strength. However, if you knew how to care for them and take care of them, they could be coaxed to many miles of service and decent fuel economy.
 

chad6000

New member
The 6.2 and later 6.5 turbo diesels weren't medium-duty diesels like the Cummins, and they suffered numerous maladies. They weren't known for their strength. However, if you knew how to care for them and take care of them, they could be coaxed to many miles of service and decent fuel economy.

Thx Kaisen, that clears it up for me. I love this era burb!
 

southpaws3

Observer
1 have an 88 burb w/ too many mods daily driver. i run a 454, nv4500,4.88 gears,38" tires. do regular maintenance get solid 14 mpg whether running,parked,loaded,empty,off w/trailer 11. parts cheap,insurance cheaper .....enjoy
 

7echo

Adventurer
I've had several Suburbans and zero issues with reliability. My current rig has 260K miles on the original engine, transmission, transfer case, axles, alternator, starter, etc, etc. Two of my power windows are giving me issues, as is the power lock solenoid for my rear liftgate.

What sort of mileage are you getting with your current Suburban?
 

Kaisen

Explorer
What sort of mileage are you getting with your current Suburban?

It's the biggest motor choice, the 8.1L (496 cu in) big block... you wouldn't buy one unless you had the need. But with 3.73 gearing and large 32.8" tires, I get about 10-11 mpg around town, and 14-16 mpg on the freeway, empty. When hauling a trailer, it gets about 10-11 mpg all the time. It's rated to tow over 10,000 pounds.

The 8.1L is a medium duty commercial motor that powers delivery vans and marine applications, and was offered in 3/4 ton and 1 ton pickups and Suburbans from 2001 to 2005/6.

The irony is that the 6.0L in a similar vintage 3/4 ton 'Burb gets maybe 1 mpg better, and might actually get less under a heavy load. Those were the only two engine choices in a 3/4 ton Sub in those years.
 

DaveNay

Adventurer
I have a '99 Suburban 2500 with the 7.4l

I once read somewhere on the internet....

It gets 11 MPG in the city
It gets 11 MPG on the highway
It gets 11 MPG towing a boat
It gets 11 MPG hauling kids to soccer
It gets 11 MPG sitting in the driveway
It gets 11 MPG if you push it over a cliff

I get 11 MPG too.
 

bfdiesel

Explorer
I have a '99 Suburban 2500 with the 7.4l

I once read somewhere on the internet....

It gets 11 MPG in the city
It gets 11 MPG on the highway
It gets 11 MPG towing a boat
It gets 11 MPG hauling kids to soccer
It gets 11 MPG sitting in the driveway
It gets 11 MPG if you push it over a cliff

I get 11 MPG too.


Lol. Yeap
 
I have a 1999 K2500 Suburban with the 7.4L and 4.10 gears.

Stock suspension and motor. I keep it in good tune and it's running pretty smooth. The only real offroad upgrade is a set of 255/85 r16 cooper ST MAXX tires. Otherwise, it's bone stock.

Driving for best economy, I get 12 mpg. Never seen 13. In winter it drops to 10.5 mpg.
Towing my little 22' Aljo travel trailer, I still get 11 mpg. It doesn't care.

Last November I used it for a two week back-country trip in the Maze district. Hanksville is 1000 miles from me. Driving just under the speed limit it got 11.5 mpg hwy. With my father driving considerably over the speed limit, it got 9. Luckily, he was covering fuel costs :ylsmoke:

In the Maze, loaded with three adults, and all the gear and food necessary for 10 days of backcountry luxury living, it ran through 43 gallons of gas in 300 miles. That was offroad, fairly slow, low-range 4x4. My notes say 6.5 mpg, and that's the number I'll use in the future for fuel calculations.
20141101_125119.jpg


I hear that the 5.7L will get in the high teens on the highway, unloaded. Falling to the low teens if it's towing.

I also have a friend who has a 2005 K2500 suburban with the 6.0L and 3.73 gears. He averaged 17 mpg on his coast to coast vacation last year with his two teenage sons and his father. No towing, they stayed in hotels.
 

rayra

Expedition Leader
We get just over 14 in our 5.3L '05 Tahoe, have for 140k mi, mostly highway. Same for its ancestor '99 Tahoe, similarly equipped. So far I'm only getting 12.5 in my 5.3L '02 K1500 Sub, but that's mostly been short trips around town. I'm hoping to milk something approaching 14 out of it on road trips.

And the post above about mpg being unchanged regardless of load or conditions definitely applies to my pickup. No matter what I haul or tow it stays pretty much the same as when empty.

Irony is just about every piece of GM iron I've ever owned gets 14mpg. '80 Chevy Luv 4-banger, '73 Formula 400 Firebird, '85 C-10 with a carb 305, both Tahoes. And now the Sub. I'm a slow learner I guess.
 
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