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6.0 versus 5.3 "flex" gas mileage?

Grey Eagle

Full Member
Joined
Nov 13, 2006
Messages
11
Hey gang,

I am very close to buying a loaded 2007 AV with the 6.0 engine.  Can anyone give me some "real world"
estimates of the gas mileage I can expect?  I can live with mediocre mileage but I'd like to get a "ballpark" relative to the 5.3L "flex" engine.
 
The 6.0 should get 1-2 mpg less then the 5.3 according to window sticker.
 
Wazbro said:
The 6.0 should get 1-2 mpg less then the 5.3 according to window sticker.

Sticker or "real world?" Any 6L owners out there? I will be buying in the spring...
 
Although I haven't driven my 6.0 Av yet, I am coming from a 6.0 Silverado SS that I put 42k miles on.? Day-to-day, I was usually in the 12.5mpg range around town.? I was occasionally in the 10s, and as high as the 14s.? Best I ever did on the highway was a tick over 17mpg, and that was after the computer was reporgrammed.? Now my SS needed premium, had AWD, and weighed a little less, and didn't have the active fuel management, but I'd think they are in the same ballpark.?

Window sticker for my SS listed 13/17 if memory serves.
 
I'm not sure on what the mpg rating is for the 6.0, but I do remember from reports that the Flex-Fuel(E85) 5.3s were getting 1-2 miles less than the mpg for the standard 5.3s. I would think you could get better mileage in the 6.0, as long as you don't have a heavy right foot >:D.

-James.
 
I cannot speak for the 6.0, but my 5.3 only gets about 15 mpg. I drive almost exclusively interstate. (80 miles to work one way) I've never seen 16mpg. I have been known to have a heavy foot though. Especially since I love the way this truck sounds at WOT.
 
betty bowtie got 14.3 mpg with her 6.0L
http://www.chevyavalanchefanclub.com/cafcna/index.php/topic,70585.0.html
 
Re: the 5.3 mileage

I just got back from a round trip from Houston to the east coast of Florida in my '07 with the 5.3L Flex engine.  Used gasoline (not E85) all the way.

2160 miles, average moving speed (i.e., excluding the time stopped) according to my Garmin GPS 77.6 mph.  >:D

MPG according to the computer 17.9 MPG.  A rough calculation of miles driven vs. gallons purchased agrees with that number.

I did virtually no driving off of the interstates, but since the highways were pretty crowded with holiday traffic, very little cruise control usage, either.

I don't have numbers for the 6.0L.  If someone would care to lend me theirs for the trip I'll be making at Christmas ...
 
I have the 5.3 and consistently get 16-17 mpg. I would say the 6.0 should get 14-15 possibly. All depends in how smooth you drive it, a friend of mine has the exact same truck as mine and claims he can only get 15 mpg.
 
Not to bring this back from the dead, but I just bought an '09 up in northern Idaho this weekend with the 6.0 and drove it down...

Got 17.3 at majorily 75 mph.

Versus the 5.3L in my '04 that NEVER, EVER got over 16.5. EVER. I mean at 55 cruising the Idaho highways I got 16.5 mpg. Just saying.
 
MPG?  who cares it is a truck.  you dont buy it for efficiency.  thats what a car is for.  I have a supercharged 5.3L and I average 14mpg. mixed city/interstate driving.  straight up interstate it gets 16/17mpg.  Is what it is.  If i have it full of friends and gear I really dont care what the mpg is.  avoids taking two vehicles.  I do feel a little guilty driving it solo and guzzling it down.
 
UtahAvySki said:
MPG?  who cares it is a truck.  you dont buy it for efficiency.  thats what a car is for.  I have a supercharged 5.3L and I average 14mpg. mixed city/interstate driving.  straight up interstate it gets 16/17mpg.  Is what it is.  If i have it full of friends and gear I really dont care what the mpg is.  avoids taking two vehicles.  I do feel a little guilty driving it solo and guzzling it down.

Well, thank you for your carefully crafted, civil response.  The full members appreciate your input.






 
Not really a direct comparison but my supercharged 5.3 is not as fuel efficient as my supercharged 6.0.  Could be the tune?
 
mikeskiw said:
Not really a direct comparison but my supercharged 5.3 is not as fuel efficient as my supercharged 6.0.  Could be the tune?

Is there a write up for supercharging the 6.0L? What all goes into it?
 
What other trucks did the 6.0 come in? Is the 6.0 in the 2007 chevy silverado 2500 the same as the one in the avalanche?
 
1320king said:
What other trucks did the 6.0 come in? Is the 6.0 in the 2007 chevy silverado 2500 the same as the one in the avalanche?
I believe that is the L76 engine. It is in a ton of vehicles, both trucks and SUV/SUTs - http://gmauthority.com/blog/gm/gm-engines/l96/

From threads I remember, I'd be going for an LQ9, which is a Gen III engine but same displacement.
 
First gen EXT's have the LQ9.

With the all wheel drive and 3.73 gears, my long term average MPG is 14.59.
 
2007 LTZ with 6.0L and 4.10 gears - 12 mpg average.  Babying it on a long trip, 14 mpg.  But this truck was set up for towing.  Which it does in style.  
 
if your trying to compare checkout Fueleconmy.gov I logged every tank for first 3 years and found this site was bang on real world if you take the time to setup your commute ect.. I did it for my last 3 vehicles. I trust it.

https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=31500&id=24636
 
Can only tell you how my 6.0 does, I have a few mods, Magnaflow muffler, Cold Air Intake, Programmer, 285/16 tires, 2.5" Ready Lift and a heavy foot, so I get 12.5 mpg and really not much better on the Highway. Solid engine though, 150,000 miles and still going strong.
 
Well I have had the truck for a week and I dont even care about the mileage. It has a GM cold air and cat back system and is the best sounding truck I have ever owned. And power is amazing with 6.0. So I am heavy footed and it is fun to drive.
 
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