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Chevy Silverado and GMC Sierra Real World MPG Numbers

176 messages,  Last post on Mar 27, 2013 at 12:39 PM

You are in the Chevrolet Silverado & GMC Sierra Forum.

What is this discussion about? Chevrolet Silverado 1500, Chevrolet Silverado 2500, Chevrolet Silverado 3500, GMC Sierra 1500, GMC Sierra 2500, GMC Sierra 3500, Fuel Efficiency (MPG), Truck

Messages Page 14 of 19

#124 of 176 silverado v6 real world gas mileage by mike537

Nov 24, 2010 (1:05 am)

hello I own a 4.3L short bed silverado work truck with the 5 speed. When the truck was new (4250 lbs) my real life mileage was around 19-20 average mpg. The worst I ever recorded was 16, and the best was 23.5 with all highway driving at 60mph.
 
Now I have upgraded the rear end from 3.23 to 3.90 and installed a supercharger. My average gas mileage with the supercharger was 16.5 mpg just highway. I then added an intercooler and took off 300lbs of weight and my total city/hwy averages 18mpg. On a full highway trip I will average 23mpg with this setup at 60mph. But I can also drain a full tank of gas in less than 2 hours if I'm really on the gas with this setup, the worst I have gotten was 11 mpg all city driving with a lead foot.
 
The stock 3.23 (or even 3.42) gears for the v6 truck in my opinion does hurt gas mileage. These trucks are not aerodynamic, and any driving above 60mph will start to decrease mileage significantly. Problem is when they add a 3.23 rear the v6 truck is taching around 1500rpms in overdrive, and there is too much throttle work needed to maintain your speed up hills and in traffic. Chevy would have done better with either a 3.08 rear so it would tach low enough (1100-1200rpms) to make up for the greater throttle play, or something like a 3.73 rear so no throttle movement would be needed cruising at 60mph.
 
Chevy could easily get a 26-27 highway mpg rating in their base model shortbed trucks if they offered a belt driven supercharged/intercooled v6 with a 3.23 rear and a 6 speed manual (with double overdrive). But they will never spend the money to do this.

#125 of 176 Re: The Answer To Question One [nitrous05] by mike537

Nov 24, 2010 (2:48 am)

Replying to: nitrous05 (Dec 12, 2005 7:52 pm)
actually the turbo efficiency idea is not that it makes more power ]to move the truck easier. This is because when you see the highest mileage with the turbo you're not going to be under boost. What makes it more efficient is the slightly greater volume of air coming in at lower rpms vs. stock. This leans out the air/fuel mixture (which is usually corrected for in the tune), and the higher volume of air is what allows for a turbo engine to create a more dense air/fuel charge.
 
for example if your car got 20 mpg, you add a turbo and no intercooler, you would be lucky to see 15mpg. So you can see it isn't the turbo or the extra power, it's simply the extra air coming in while under vacuum (not boost). What you do with that air in terms of cooling and tuning is what generates the extra efficiency.

#126 of 176 Re: Chevy Truck Gas Mielage [hutch54] by mike537

Nov 24, 2010 (3:33 am)

Replying to: hutch54 (Jun 07, 2009 11:07 am)
hutch, your 4x4 suburban does not get 24 mpg on the highway.
 
The best mileaged 4x4 suburban is the new 5.3L 4x4 with 3.08's and the double overdrive, on the highway it gets 21mpg, 22 is great driving, 23 is stretching the truth but perhaps possible, 24 is bullshit. The 2wd tahoe hybrids don't get much more than 22 hwy. Fullsize 2wd pickups with the 5.3 and 6speed get at best 22mpg. S10 4.3L's with the same 3.08's get 26mpg at best. you are full of shit.

#127 of 176 Re: Chevy Truck Gas Mielage [hutch54] by banster

Dec 11, 2010 (3:16 pm)

Replying to: hutch54 (Jun 07, 2009 11:07 am)
I also agree there is no way you can get 23-24 mpg with a 4x4 suburban!!
I also don't think your brother gets 12 mpg with his 1/2 ton ford unless he runs the nuts off of it, seeing as mine gets 18 mpg!

#128 of 176 Chevy Truck Gas Mielage by daddyb25

Dec 17, 2010 (8:23 pm)

well i have a 07 chevy silverado, crew cab with the 5.3, im getting 12-13 mpg, i actully just took it to the dealer today and they say its fine ugh how do u get better mpg out of these trucks, this is rediculas!!!

#129 of 176 Old for New by narg

Dec 18, 2010 (10:07 pm)

Hi all, I'm trading in a 2000 Silverado Ext Cab with the older 5.3L V8 that would easily get 21 to 22 MPG highway driving (though my wife got 24 MPG once or twice, no tailwind either!) for a new 2011 Silverado 5.3L Crew Cab.
 
I attribute most of the over 20 MPG rating to a hard bed cover. It was a 4 piece folding cover that I loved. I plan to get the 3 piece cover that GM offers via the dealerships, but in a few months after I swallow the Tag/Title/Tax costs first.

#130 of 176 Re: 08 silverado losing gas mileage [maybe1] by travelcheve

Mar 01, 2011 (3:04 pm)

Replying to: maybe1 (Mar 25, 2010 1:58 pm)
Im having the same problem did you ever get it figured out?
im only geting 11 mpg in town and 13-14 on highway. they say nothing is wrong.

#131 of 176 Re: 08 silverado lost gas mileage by aaroncorpus

Mar 05, 2011 (8:42 am)

Replying to: maybe1 (Mar 29, 2010 5:06 am)
My 2008 silverado used to get 18.5MPG HWY, and 13.5MPG city, but now I get 11.5MPG city, and 15.5MPG HWY. Took to dealer and they were no help, said could find no problems with truck, I think we got a big lemon! The only reason I bought this truck was because of the better MPG, I'll never buy a Chevy ever again unless this porblem can be fixed?

#132 of 176 Re: 08 silverado losing gas mileage [travelcheve] by gmcustsvc

Mar 15, 2011 (11:33 am)

Replying to: travelcheve (Mar 01, 2011 3:04 pm)
travelcheve,
The best fuel economy possible is the direct result of proper maintenance and good driving habits. Listed below are GM's recommendations to achieve the best mileage possible. The first group are things to consider for your vehicle, while the second are tips relating to your driving habits.
 
One of the major contributors to poor fuel economy are under inflated tires. Tires low with pressure create drag that the vehicle’s powertrain must overcome, wasting dollars in fuel. Always keep your tires inflated to the proper pressure as shown on the vehicle placard. This not only serves to increase gas mileage but cuts down on tire wear, further decreasing your costs per mile.
 
A vehicle that has a dirty air filter can’t efficiently draw air into the engine. This restriction forces the engine to expend energy to "breathe" wasting fuel in the process. Change recommendations are found in your vehicle Owner’s Manual.
 
Always use the proper viscosity oil in your engine. Oil that has a higher than required viscosity will create more drag on the internal components of the engine causing more work for it, especially when cold. Each Owner’s Manual contains information on the proper type of oil for your vehicle. Look for the "starburst" symbol on the front of the bottle, and the SM rating on the API circle on the back label. If you are in doubt, stop by your dealer for an oil change, and any other services required. Most current GM vehicles are equipped with oil life monitors to further assist on the "when" to change your oil. (Aveo/Wave/Optra/Epica currently do not have oil life monitors).
  
Note: GM Vehicles DO NOT require additional engine oil additives. Some additives may cause harmful effects to the internal seals and additionally void the terms of your vehicles New Car Warranty.
Purchasing higher than required octane fuel is a waste of money. Using higher octane fuels in a vehicle that only required regular unleaded fuel will neither increase performance nor improve gas mileage. In all cases refer to your owner’s manual and ONLY use the octane rated fuel recommended for your vehicle.
 
Even though current GM vehicles have 100,000 mi (160,000 km) service intervals for spark plugs if your vehicle is at that point in its life, have the spark plugs changed to assure proper running and continued efficient, trouble free operation.
 
Avoid quick/full throttle acceleration from a standstill in town and high cruising speeds on the interstates. While the optimum MPG for highway cruising speed varies from vehicle to vehicle, faster is almost always worse. If your vehicle is equipped with a Driver Information Center that displays Instant Fuel Economy, select that readout and vary your cruising speed while on the highway. The display will change continuously with uphill and downhill sections but you should quickly be able to identify on level ground the speed range that your vehicle does the best in. Avoid leaving unnecessary items in your trunk. It takes power to move increased weight and that means more gasoline consumption and reduced performance. While the change may be slight, multiplied by thousands of miles, it all adds up. Your vehicle uses much more fuel when the engine is cold. This is especially true in the winter months when the engine will take the longest to warm up. Combine errands or trips so that the vehicle only needs to warm up once to encompass many different stops.
Please also feel free to get a second opinion from a different dealer.
Christina
GM Customer Service

#133 of 176 Re: 08 silverado lost gas mileage [aaroncorpus] by gmcustsvc

Mar 17, 2011 (7:00 am)

Replying to: aaroncorpus (Mar 05, 2011 8:42 am)
aaroncorpus,
I would recommend having your vehicle looked at by an authorized GM Dealer. I would also recommend reading post #132, as there are some helpful tips. Please keep me updated as to what the dealer says.
Christina
GM Customer Service

Messages Page 14 of 19

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