Jump to content

Help with gas mileage!

Trevor Myers

By Trevor Myers
in Troubleshooting & Recalls

 Share

Recommended Posts

Trevor Myers Enthusiast

Trevor Myers

Posted
Posted

Alright guys help me out,

 

In my 2017 silverado Lt I have recently put a 2.5" leveling kit, with 285/70 venom power terrains on a 17x8 moto metal wheel (stock is 265/65r18), resonated tip (for looks) and a k&n drop on filter. My best average was 19.9 and is now 15.4!? I was expecting a drop but not 5 mpg!

  • Like 1
14 Silvy Enthusiast

14 Silvy

Posted
Posted

You need to hand calculate it with the bigger tires your computer is showing you traveled less miles due to the larger tires. Also there will be a drop due to the size difference in tires and the rolling mass is increased and the contact patch is larger also.

Sent from my SM-G988U using Tapatalk

Trevor Myers Enthusiast

Trevor Myers

Posted
  • Author
Posted

How do I calculate it? I know i have more rubber and friction and all that. But these tires are actually 3lbs lighter that BF ko2's and all the research ive done I've never heard of anyone losing that much. Also is 22 less rotations per mile alot?

aseibel Senior Enthusiast

aseibel

Posted
Posted

If you didn't recalibrate the speedo, your readings are going to be something like 3-4% too short.

 

So take the old tire's rev/mile and divide by the new one. That will tell you what ratio you need to multiply your mileage by to get accurate readings.

 

That's still not going to improve your mpg number by very much. Raising up the front end & adding wider tires kills your aerodynamics. 

Donstar Senior Enthusiast

Donstar

Posted
Posted

It takes very little to impact the mpg's on our trucks.  They achieve optimal efficiency when stock, unladen and driven gently.  Any changes to these factors and fuel consumption will increase.    Your mpg's, with the changes you've made, sound right based on what I'd expect.  I'm sure your truck looks good and I'd switch out of the mpg screen.  On my last truck I put on larger, heavier tires and took a significant hit at the gas pump.  I simply changed my driving behavior by eliminating an unnecessary trip or two during the week.  It sometimes costs to look good! 

  • Like 2
Eddie 70 Senior Enthusiast

Eddie 70

Posted
Posted

I went from factory 18's to factory 20's and lost 2 mpg. The weight difference was about 20lbs per wheel heavier. Factory wheels and tires.........

Phil Murray Enthusiast

Phil Murray

Posted
Posted
12 hours ago, Trevor Myers said:

Alright guys help me out,

 

In my 2017 silverado Lt I have recently put a 2.5" leveling kit, with 285/70 venom power terrains on a 17x8 moto metal wheel (stock is 265/65r18), resonated tip (for looks) and a k&n drop on filter. My best average was 19.9 and is now 15.4!? I was expecting a drop but not 5 mpg!

⁸

Phil Murray Enthusiast

Phil Murray

Posted
Posted

Part of the answer is -

What was your old worst and overall averages.  You want looks or you want fuel econ?

amxguy1970 Senior Enthusiast

amxguy1970

Posted
Posted
13 hours ago, Trevor Myers said:

Alright guys help me out,

 

In my 2017 silverado Lt I have recently put a 2.5" leveling kit, with 285/70 venom power terrains on a 17x8 moto metal wheel (stock is 265/65r18), resonated tip (for looks) and a k&n drop on filter. My best average was 19.9 and is now 15.4!? I was expecting a drop but not 5 mpg!

Your new tires are approximately 1.1" taller so that is 3.5% larger which means you need to multiply your current mileage 1.035 (that is 3.5%). So your 15.4 mpg is really 15.9 mpg. As others have noted, your tires are heavier (stock were P-rated and your new tires appear to be LT rated), they are wider, taller and your truck is taller with the nose more up as opposed to having some aerodynamic rake. All that can certainly add up to nearly 4 mpg at highway speeds, that is a bunch going against the factory aerodynamics and weights. Did you also remove your air dam or do anything to it? Not much you can do but make sure the tires are inflated properly, make sure the air dam is on, maybe add a rear block to angle the nose down a hair for better aero (not lowering it) or lowering the truck a little, 2.5" is awfully larger and will add wear and tear on the front of your truck along with the heavier and larger tires. Gotta pay to play, I understood that when doing my truck so I added a 1.5" level, P-rated tires 1 inch larger but stock width and only trimmed the air dam instead of removing it, I lost between 1-1.5 mpg over stock. 

 

Tyler

Bash74 Enthusiast

Bash74

Posted
Posted

Some people say when they switch to winter blend gas the milage goes down. Are you on a winter blend now.

Sent from my SM-G975U1 using Tapatalk

  • Like 1
TXGREEK Senior Enthusiast

TXGREEK

Posted
Posted
Alright guys help me out,
 
In my 2017 silverado Lt I have recently put a 2.5" leveling kit, with 285/70 venom power terrains on a 17x8 moto metal wheel (stock is 265/65r18), resonated tip (for looks) and a k&n drop on filter. My best average was 19.9 and is now 15.4!? I was expecting a drop but not 5 mpg!

Tires, it’s your tires. Add air, get a tuner (SuperChips), switch back to stock air filter and go from there.


Sent from my iPhone using Tapatalk
aseibel Senior Enthusiast

aseibel

Posted
Posted
31 minutes ago, Bash74 said:

Some people say when they switch to winter blend gas the milage goes down. Are you on a winter blend now.

The OP is from the other side of the state from me. We are definitely on winter blend now. I kind of ignore the fuel economy numbers from October to April and focus on the summer months, haha.

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted
2 hours ago, Bash74 said:

Some people say when they switch to winter blend gas the milage goes down. Are you on a winter blend now.

Sent from my SM-G975U1 using Tapatalk
 

Since September 15 we all have been. I post the following about twice a year at each change when this topic comes up: 

 

The difference between summer- and winter-blend gasoline involves the Reid Vapor Pressure (RVP) of the fuel. ... The US Environmental Protection Agency (EPA) says conventional summer-blend gasoline contains 1.7 percent more energy than winter-blend gas, which is one reason why gas mileage is slightly better in the summer.

 

Winter gas accounts for a MAXIMUM of 1.7% of the mpg loss. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      www.enginelabs.com/news/what-i-learned-today-bearing-clearances-vs-oil-viscosities/     www.enginelabs.com/news/oil-viscosity-can-the-numbers-be-misleading/ The Big Lie… Coming full circle to the reason Lake discusses the Porsche engines in particular. Based on the 2000 samples in the SPEEDiagnostix database, increasing the oil viscosity in these engines, even those run on the track, showed no significant difference in results.   The smoking gun was in the oil chemistry. That is where the data shows higher instances of more wear. Molybdenum was the key; the higher the amount, the less the wear. Speed postulates that higher viscosity oils have more thickeners to artificially inflate their viscosity numbers. These thickeners lose viscosity under shear, and the result is that not all oils of the same viscosity have the same shear stability.   Having enough viscosity is the most important characteristic, but according to Speed, once that required viscosity level is reached, additive chemistry matters more than additional viscosity. Speed also states, oil pressure problems on the racetrack aren’t a viscosity problem; it’s an oiling system problem. Running a thicker oil is just a band-aid for an underlying oiling system problem.
    • Grumpy Bear
      Some Assembly is Required

      By Grumpy Bear · Posted

      Can it still be Assembled II?   Viscosity on the decline by various means. Heat on the rise making that worse. Engine RPM in the tank. Smaller motors with more boost trying to emulate an electric motor. Full torque, zero rpm. Then we will triple the OCI. Argh.    But wait....there is more. LSPI has pushed a shift from Ca to Mg and as that cost more PLUS the run to lower sulfur compounds the TBN is moving in the wrong direction for the increased OCI's demanded.    That not being enough to placate a demand for a parameter they can't measure the other sulfur bearing compounds are also under attack. That would be zinc and phosphorus sulfonate compounds. To some degree those are being replaced with boron esters and others, i.e. titanium ect. All of which have shorter service lives. And there there is the "Secrete Sauce" marketing for AW adds that 'Can't be detected by UOA's" but trust me because I (the blenders) never ever lie.    Spoiler alert; ALL additives are sacrificial! Smaller amounts of the old blended with less robust versions of the new do not equal longer service lives. So what are the blenders recommending? Wait for it.......   MOVING THE GOAL POSTS! OMG      Let's declare the long standing TAN/TBN crossover irrelevant and tell people that soot is a great 'graphite' based lubricant which can aid tribo films. Wait, what? Let's declare that the standards used for oxidation and nitration were to conservative and can be expanded. Let's tell them that because GDI fuel dilution, although being a VISCOSITY KILLER and an acid generator is actually okay because we have better base oils that limit viscosity failure limits. (Said knowing this is measured in fractions of a centipoise and in bases not commonly used in shelf oils)   Lying from the heart is not just the new normal but we have a public, a very young public, that is so ignorant of the facts and so sure of their "RESEARCH" into AI driven models base in regurgitated  instead of scientific research based unvarnished, peer reviewed FACTS that the incoming guard is loosing their grip on reality and the OEM's are tickled pink while the blends bend the knee.    You have an ever limited set of tools to work with. And sooner or later those will be taken from you as the API and the EPA strangle the last remaining fluids from the system. What you have left is your wits. If you care to use them.    At some point in the very near future it will not longer be possible to do "What is best for the machine", and be replaced with "The best you have access too". You WILL be rewarded with half the life and twice the cost. That isn't that hard to predict.         
    • Chuck FB
      Software Update

      By Chuck FB · Posted

      I trust you saw the other comment where he knew what he was talking about !. Yes, these darned newer vehicles with all their so smart they are stupid technology, goes and drains the battery down. As you might see my other comment, I installed a Noco 5 battery tender under the hood and at this point still have the cord routed so I have to lift the hood and then plug it in but am typically parked in a garage or a shed so its not risking the engine hood in the wind. That way I am assured or hopefully so of not finding I have a battery drawn down and can't even start the truck and that also damages the battery to draw it down too far. 
    • Chuck FB
      Software Update

      By Chuck FB · Posted

      I guess no surprise my guesses were wrong !, at least now I know if I ever happen to see it grayed out in my own truck as to what is going on.    I never happened to catch my truck with it grayed out, it seemed every time I would test to see if there was an update it never found anything and yet more than once I would check to see if there was an update and there was nothing, then a day later or even that same morning I would drive to town and after more than one engine shut down in town as I did my errands it would pop up that there is an update now ready to install and the only place I have a connection to the internet is at home by wifi so its not as if it grabbed the download while driving. I don't trust these new vehicles due to all the crap they can decide to do while sitting for some days not running and run the battery down so most of the time if I know the truck will sit for a few days I plug in the battery tender I have mounted under the hood and so the only time the truck must have downloaded software was when it was sitting in the garage where the signal is awful but I have that tender plugged in and somehow it managed to download it. I honestly detest all this crap, way to easy to leave a person stranded.    Since I don't trust any of it I don't do the install of the already downloaded software until I get home and sometimes have even sat in the truck to watch what its doing as its going through the process to its conclusion as its not like it is set up that it will tell you the next time you fire up the engine that the update that was initialed actually installed or installed properly. Yes I can go into the updates and see the list. After I go through the install where I feel its safe to do so in case it breaks down as a result, I will plug in the battery tender after the fact to recharge as I don't know how much power its taking just to do the install and that can take a while for it to install. 
    • nfisherman
      Software Update

      By nfisherman · Posted

      Thanks for the reply. All settings were correct and the engine was off, as it was supposed to be. It turned out to be something simple. I took a drive for about an hour. I must have had a low battery without knowing it. The voltage gauge on the display looked ok. At the end of my drive, I shut off the engine and the update prompt came up and it updated normally. It’s ironic because one of the features of the update is a reduction of battery drain. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...