25 mpg Silverado Z71

[McCool]

I have a 2006 Chevy Silverado Z71 that can use regular unleaded or any of the ethanol mixtures. I noticed fuel economy is not very good with the ethanol, so I decided to try some hypermiling techiniques on a trip I made. I wanted to keep things simple, so the only things that I concentrated on was keeping the tach below 1,700 while accelerating and going up hills and I would also put the truck into nuetral when going down hills.

I normally get about 17 mpg with this vehicle. On the first leg of the trip, I had heavy headwinds (30 mph with gusts to 50) and was driving through rain most of the way. On that leg, I was able to get just shy of 20mpg. The next day was calm with no water on the road and I was able to get 25 mpg with this vehicle.

I thought this was pretty good for a truck with available 4WD and a 327 V8.

[roflwaffle]

If you optimize for gearing, maybe add a relatively aerodynamic bed cover, I think you could easily break 30mpg.

[Frank Lee]

If I could break 20 again I'd be tickled pink. What's yer truck got?

[roflwaffle]

My bets on cylinder deactivation, and dammit, I'd bet my left nut that even a full size truck could get ~35mpg at 55mph w/ the Phil Knox aero treatment, LRR tires, and some way to manually actuate the cylinder deactivation doohickey.

My 2008 Chevy Tahoe has the Eaton Active Fuel Management system (internally called "Displacement on Demand"). After 24k miles, and using the ecm provided instant fuel economy, I can see the change from 18 to 26 mpg on a flat road at 55 mph very day, both directions. This includes trailer towing(boat and hay delivery).

[bucknmusky]

McCool, sorry I did not find your fuel log or vehicle in the garage... Could you fill in the details, you say

"I thought this was pretty good for a truck with available 4WD and a 327 V8."

does this mean you have the 5.3 liter 4WD or the 4.8 liter base model 2WD and put the Z71 stickers on it?? I have the 2002 1500 Z71 with 4WD and have been tracking fuel economy for 32,000 miles in the past 18 months and my best tank was 21.06 mpg with a lifetime average of 17.32 mpg. I have a scangauge and can achieve high mpg coasting down hills and driving on flat roads at slow speeds but overall results are going to even out.
If you have discovered some trick to coaxing out 25 mpg from these rolling bricks without any modifications (computer, areodynamic, or mechanical) Believe me you have our un-divided attention.

[stvbldso]

I'm guessing he has the 5.3L engine (323 cubic inches). My company "brick" has that engine, an automatic transmission, 2-WD, and a soft tonneau. I don't bother to employ all of the tips and tricks that are discussed here while driving it. But....around town, it's typically a 17 MPG thing. On the road, running at the speed limit (on cruise) it is a regular 20-21 MPG thing, and I have seen the better side of 24 on several occasions. I too have not bothered to post logs (busy), but I do keep hand-calculated mileage logs in all of my vehicles, and I fill them up the same way each time (not to the pump "click-off" point). I have to admit that I am pleasantly surprised that Chevrolet's ads seem to be correct - "20 plus MPG". I know that mileage figures in the "20s" pales in comparison to what some of the real experts here are doing with hypermiling the small, efficient, modified cars, but....the pickup truck thing is unavoidable for some of us. And "twenty-anything" is a great figure for a full sized truck. Congrats on your mileage!

[taco]

i managea a 200 mile trip in my dads 08 silverado crew cab lt 4x4 z71, with the 5.3(327) 4 speed auto w/ 20's. i watch the gauge on the dash, and u can hear the cyc deactivation in his duel flowmasters, it sounds kinda funny. i got just shy of 25, i think it was 24.8, never went over 65mph.

but he gets 15-16 out of it normally.


still great for a full size.



i also hook up the sg to my friends 01 or is it 02 silverado reg cab 4.8 4x4 5 speed, and found it did 30 mpg at 40mph.......and 5th was useable down to abotu 15-20 mph. u could accelorate right out of it no studder. but a tiny bit of peddle it was 15mpg. haha just goofing off alittle i got low 20's mpg.
(k&n intake, eldbrock header, true duel exhaust w/ thrush and a diablo tune. not exactly stock and required premium)

[lovemysan]

My suburban does 18mpg average with the cruise on 70-72mph. It will do 25mpg at 45-50mph. Are you guys going by the DIC or hand calculating. I found that the DIC in my burb is heavy optimist. I have gotten as good as 22mpg in mixed use but it was impossible to maintain that. The DIC was reporting 24mpg+ of course. I wish it had the cylinder deactivation. I feel the system is good for 20% improvement around town, more in skilled hands.

[bucknmusky]

All my results are based on hand calculations. The 2002 does not have the driver info center or cylinder deactivation, wish it did. on anoter site I also frequent GM-Trucks.com there are guys on the forum getting their computer reprogrammed to eliminate cylinder deactivation so they have all V8 all the time. I don't know why...Does anyone know if Cylinder deactivation can be programmed into a computer program that does not have it??

[lovemysan]

Originally Posted by bucknmusky

All my results are based on hand calculations. The 2002 does not have the driver info center or cylinder deactivation, wish it did. on anoter site I also frequent GM-Trucks.com there are guys on the forum getting their computer reprogrammed to eliminate cylinder deactivation so they have all V8 all the time. I don't know why...Does anyone know if Cylinder deactivation can be programmed into a computer program that does not have it??

My results resemble yours closely. My average FE is around 15mpg all city. I'm considering a chip. I've heard of some people getting better mileage with chips on the truck forums.