Increased Fuel Economy, Am I Crazy?

[oosik]

I have a 2018 Ram 2500 HD Power Wagon. 35K miles. I normally average - 16.5 mpg. If I watch my speed OR drive with the wind - I can get 20 mpg. Drive against the wind or over 70 mph - I'll be lucky to get 13 mpg.

Drive against the wind AND over 70 mph - better know where I am and where the gas stations are.

 

[mjonesnh]

Not as drastic as your experience. Ran Motorcraft 5w20 Synthethic blend from new till this spring in my 17 Ford Escape. Switched to Mobil 1 Extended Performance Full Synthetic 5w20 and my mileage went from 27.7 to 29.9, a gain of 2.2 mpg more per gallon mostly local driving. On a trip of 300 miles the difference goes to 3.0 more per gallon. Almost 10% difference just by changing oil brand in same weights.

 

[DarkBlack]

and for some reason when it is raining seems to drop mileage even if there is no extra wind.

It takes energy..power, to move water. Every raindrop is smacking your vehicle and being instantly accelerated to your vehicle speed. This takes energy.
Your tires are plowing through water on the road. Ever check the mileage of boats?. It takes energy to throw that rooster tail of water spray off each tire. Try physically throwing water up with your cupped hands, like your tires do during rain, for a few second and see if You don’t get tired

 

[ArlyA]

Not sure air temps were mentioned by the OP.
-----------------------------------------------------
Air temperature has a significant impact on a vehicle's fuel economy:

• Cold weather
  Fuel economy can drop by 15% in the city and up to 24% for short trips when the temperature is 20°F compared to 77°F. This is because:
  The engine needs more time to warm up
  
  • 
    
  • Engine oil and drive-line fluids are colder, increasing friction
    
    
  • Tire pressure is lower, increasing rolling resistance
    
    
  • 
    Aerodynamic drag increases due to denser air
    
    
    

 

[LittleBittyBigJohn]

Not sure air temps were mentioned by the OP.
-----------------------------------------------------
Air temperature has a significant impact on a vehicle's fuel economy:

• Cold weather
  Fuel economy can drop by 15% in the city and up to 24% for short trips when the temperature is 20°F compared to 77°F. This is because:
  The engine needs more time to warm up
  • 
    
  • Engine oil and drive-line fluids are colder, increasing friction
    
    
  • Tire pressure is lower, increasing rolling resistance
    
    
  • 
    Aerodynamic drag increases due to denser air
    
    

This is for sure a possibility. We are entering fall now.

Otherwise my driving habits have remained the same.

 

[nyone]

I’m not a gas mileage freak but out of something to do I track it on longer trip. I hated the 55 mph speed limit when it was a thing but it does make a big difference on fuel mileage. It’s also something you can control. Driving 65 mph vs 75 mph makes a difference. I drive a little over the speed limit but driving on a 2 lane road you are usually driving slower.

Tailwind will really boost your mileage. If you have a 15 mph tailwind and are driving 75 mph your vehicle thinks it going 60 mph as far a wind resistance and fuel mileage.

I find this to be quite opposite with My 2012 suburban. The 6.0l and 6speed seam to like 75-80mph quite a bit more than 55-65mph. I got 3mpg better between 75-80mph, calculated not via the dash.

 

[dodge man]

I find this to be quite opposite with My 2012 suburban. The 6.0l and 6speed seam to like 75-80mph quite a bit more than 55-65mph. I got 3mpg better between 75-80mph, calculated not via the dash.

I’d say that’s an unusual case. Wind resistance is exponential based on your speed.

 

[jonsstihl]

yes, force required goes up with the square of the velocity.

My coworker has a 2023 sierra with the 5.3L and he said the same thing. we think it has something to do with the transmission not making it into 10th gear at slow speeds but once you get above 75mph it gets there.

 

[Jstpssng]

I found that my old '98 Sierra with 4.3 V6 got it's best mileage at around 65. As already mentioned, it stayed in high gear at that speed.
Conversely, as it got older cold weather really affected it. One cold snap we had it kept tripping codes, just because of the weather.

 

[Renze]

I guess if they put some heavier 15W40 oil in, it might be a mpg gained switching to 5W40, especially if you have lots of shorter trips where the oil spends most of the time warming up.

On my 2007 V70 diesel, switching from 0w/30 fuel saving lightweight formula according to manufacturers recommendation, to 10w/40 Castrol wear diminishing formula, my oil consumption went from 1 liter per 3000km, to 1 liter per 30.000km

Fuel consumption i never compared, giving the cost of 0w/30 the savings on oil are greater than the savings on fuel. I do 50mpg anyways.

Also, after an oil change on saturday and a short trip to my parents on sunday, say 20 minutes of running to distribute the anti wear film on all the rotating components, on monday morning cold starting after a mild frost, i could hear the difference, it didnt take 20 seconds of clattering before sounding right.

In fact the 2006 model year had problems with cam and follower wear, it was the first year they started prescribing 0w/30. My 2007 already has a cam with better hardening.

Fuel saving long life oils are invented for the bean counter selecting a company car based on average fuel consumption and average maintenance cost up to 200.000km when lease cars get dumped into the used car trade.

But if you want to drive beyond 600.000km you better get rid of that fuel saving junk because it is not saving engines...

A contractor here, his Fendt 818 had 500hr oil change intervals. He changed every 250hrs because the oil smelled and looked not OK at 500hrs.

 

[newbury]

Not as drastic as your experience. Ran Motorcraft 5w20 Synthethic blend from new till this spring in my 17 Ford Escape. Switched to Mobil 1 Extended Performance Full Synthetic 5w20 and my mileage went from 27.7 to 29.9, a gain of 2.2 mpg more per gallon mostly local driving. On a trip of 300 miles the difference goes to 3.0 more per gallon. Almost 10% difference just by changing oil brand in same weights.

"Synthetic Blend" in Motorcraft has been shown to be poor compared to Full Synthetic Motorcraft.
Check out Bob is the Oil Guy it's on there somewhere..

 

[Hay Dude]

I don't doubt you at all. I am just at a loss of what it could be.

I would think it could just be getting broken in real good, too.
My Cummins was a little underwhelming on fuel economy when it was new & tight. Now it has 60,000 on it and gets better MPGs than ever.

I’m not one to perseverate over fuel economy as I just need a truck that can get the job done

 

[LittleBittyBigJohn]

I would think it could just be getting broken in real good, too.
My Cummins was a little underwhelming on fuel economy when it was new & tight. Now it has 60,000 on it and gets better MPGs than ever.

I’m not one to perseverate over fuel economy as I just need a truck that can get the job done

That is entirely possible from what I hear.

As far as economy, it is my primary transportation, but I put it to work to pay its own payment and a little pocket money. So, I pay a little attention to the fuel economy.

 

[dodge man]

When it comes to fuel mileage it’s sometimes tough to separate reality from a fluke. You get some kind of tailwind and get great fuel mileage and think it was the oil, gas, bug deflector, or bed cover you put on.


It’s proven that synthetic oil and gear lubes can improve your fuel mileage. But how much? I’d say less than 0.5 mpg and probably more like 0.1 mpg. Probably the only thing an average person can do to improve their fuel mileage is tires. There are tires that get better fuel mileage but of course are a pure road tire. Once again probably not even a 1 mpg increase.

 

[LittleBittyBigJohn]

When it comes to fuel mileage it’s sometimes tough to separate reality from a fluke. You get some kind of tailwind and get great fuel mileage and think it was the oil, gas, bug deflector, or bed cover you put on.


It’s proven that synthetic oil and gear lubes can improve your fuel mileage. But how much? I’d say less than 0.5 mpg and probably more like 0.1 mpg. Probably the only thing an average person can do to improve their fuel mileage is tires. There are tires that get better fuel mileage but of course are a pure road tire. Once again probably not even a 1 mpg increase.

I hear what you are saying and have had that experience most of the time. Although I messed up my milage way worse than the .5 MPG with big tires when I was younger.

Right now though my "fluke" is going on 3,000 consecutive miles. I'm leaning toward it braking in, cooler weather, and better oil combined.

 

[EddieWalker]

I bought my 2012 F150 with 5.0 gas engine brand new, and I've done every oil change at 5,000 miles with Motorcraft Synthetic blend 5w-20, Motorcraft oil filter and air filter. Walmart keeps them all in stock!!!

Right after I change my oil and filters, my mileage goes up. Normal is 15.5 and it will go up to 16.5 or even hit 17 for a little while, but then it works its way back down to 15.5 mpg.

A year or so ago, I had to drive to Dallas, and I was curious about Ethanol Free gas, so I filled up with that before the 4 hour round trip drive. It's 75 mph each way with some areas that where slower, some stop and go traffic in the DFW area, and maybe some areas where I might of gone a little faster. My fuel mileage hit 20 mpg!!!

I thought I had found the secret for better mileage, so I kept buying the super expensive Ethanol Free gasoline, but once back in town, and running around for work, it went down to 17 mpg, or even a little lower. When I did the math, it wasn't worth the extra cost to buy it, so I'm back to using the cheapest gas at the station.

 

[Paystar]

I've had my truck for several months now and have put 15,000 or so miles on it. I got it with around 25,000 miles and am up to about 42,000 now. The whole time I've had it I've gotten around 16.5 MPG empty and around 12.5 on an average hauling trip. I had the dealership change the oil until it got out of the 36,000 mile warranty and I did my own at around the 40,000 mark. Immediately after changing the oil my unloaded average is up to a little over 19mpg and my haul has bumped up to a little over 15mpg. I took an unloaded trip with my wife that was about 600 total miles and we got almost 22mpg. Seems rather odd to me? I used Rotella T6 and an Autozone K&N filter. The immediate change makes me think the oil caused better fuel economy but I have never heard of that before. What say you?

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On my VW Tiguan2.0 turbo and F150 5.0 litre, I saw a 1 US MPG increase when I started doing my own changes and using Petro Canada Supreme Synthetic 5W30 over all my past dealer services.
Obviously no scientific proof, just going by dash display.

 

[garry1p]

My Honda was getting around 27.4 for over 50,000 miles with OEM tires.

Had Michelin Defender tires put on and now 26.4 over 10,00 miles. However; the Defenders hold the road a lot better in wet conditions.
A loss of 1mpg will add up over time but the Defender rides better.