Help with gas mileage!

[Bash74]

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. 

Mostly correct but states that are more strict on air quality adjusts the dates. California and a few other extend the date on summer blend and have to use earlier because summer blend is cleaner and they want it used more.
I never notice much change on mpg so its not really a concern. Also I never have to deal with ethanol in the gas.


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[dieselfan1]

13 hours ago, Grumpy Bear said:

Biggest influence on mpg is your right foot

No one likes to hear that

But.....

I get 15-16mpg on a 9" lift with 37"s.

Take your foot off the firewall.

[Grumpy Bear]

1 minute ago, Bash74 said:

Mostly correct but states that are more strict on air quality adjusts the dates. California and a few other extend the date on summer blend and have to use earlier because summer blend is cleaner and they want it used more.
I never notice much change on mpg so its not really a concern. Also I never have to deal with ethanol in the gas.


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The difference between summer and winter fuel is the RVP which is adjusted with butane. Winter gas gets more butane to raise the vapor pressure. Summer gas has less. You can google this or take my word for it as an FCC/ISOM unit operator for Chevron making your gas. (retired).

 

News travels slow and rumors die hard.  

 

https://www.eia.gov/outlooks/steo/special/pdf/mtbe.pdf

 

This stuff is always changing. 

[Bash74]

The difference between summer and winter fuel is the RVP which is adjusted with butane. Winter gas gets more butane to raise the vapor pressure. Summer gas has less. You can google this or take my word for it as an FCC/ISOM unit operator for Chevron making your gas. (retired).
 
News travels slow and rumors die hard.  
 
https://www.eia.gov/outlooks/steo/special/pdf/mtbe.pdf
 
This stuff is always changing. 

You are very sensitive. I didn't say anything about the science. I said mostly because you said we are all on winter which is not true. California changes winter to summer 1 April and summer to winter 31 Oct. Arizona and Texas doesn't have a 15 September change over. This goes back to my original asking if the OP was already on winter.

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[LDM]

If you were worried about gas mileage, why did you modify your truck with a lift and larger tires?

[aseibel]

4 hours ago, Grumpy Bear said:

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. 

Grumpy, what are some of the other reasons that summer gas mileage is better? The internet says the 1.7% extra energy is only 1 of them. I can't find the rest.

 

I know you like data. Here's 370 tanks of gasoline charted over 7+ years in my old beater. Lifetime average economy of 28.47 mpg.

 

If the 1.7% is all of the difference, it should only vary about 0.5 mpg from winter to summer. but I can see a seasonal trend that looks more like 5 mpg difference.

 

Now don't think that can all be attributed to idling time: No remote start and I parked in an attached garage for all but 1 winter, so I rarely let it warm up for more than 30 seconds before driving. And majority of trips are probably 100 miles average, since most driving was for work. So winter warm up idlling time was only a tiny fraction of fuel usage. 

 

I'm curious what you think of this data.

[Grumpy Bear]

2 hours ago, aseibel said:

Grumpy, what are some of the other reasons that summer gas mileage is better? 

 

I'm curious what you think of this data.

I think it looks just like mine  Good job sir! 

 

Biggest drag on winter mpg is....ready for this? Viscous drag. In the summer, even on a cool night (shift workers) the 'initial' viscosity of motor oil is maybe 60-70 cSt. On an average winter day more like 5,000 cSt. You've seen this and know it well. Oil poured at room temperature v from the freezer. Now think what this is like for wheel bearing grease. Diff fluid, transmission fluid. Much of these fluids are surrounded in metal it also has to heat to operating temperature. Just over all larger temperature differences. Once fully to temperature the running viscosity is more in the range of 5 to 10 cSt. In the summer you can get it down to 3 to 5 cSt. 

 

Add to this that the fuel maps for lower AIT's are quite a bit richer. Winter air is denser. Tire pressures get away from people in a hurry running 3 to 5 psi low for weeks at at time. And yes, some remote starts. People tend to make their trips shorter which results in allot more cold starts and motors never reaching full heat. For some never.

 

Then there is also things like snow, water, slush and ice. All use more fuel than dry hot pavement. Did I miss anything?

 

[Grumpy Bear]

3 hours ago, Bash74 said:

You are very sensitive. I didn't say anything about the science. I said mostly because you said we are all on winter which is not true. California changes winter to summer 1 April and summer to winter 31 Oct. Arizona and Texas doesn't have a 15 September change over. This goes back to my original asking if the OP was already on winter.

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Nah, hide like a rhino. Your post was below mine and I though you were asking me not the OP. My bad. My point wasn't about dates. It was about fuel blends and there effect on economy. I live now near Chicago. All sorts of strange fuel rules here. I don't often visit those five counties but when I have to buy fuel there it burns, economy wise, just like my local blends. Just like the E-0 I buy in Iowa as well. They are all very close in BTU content up to E-10. About UNL88 fuels things start to change.

 

Is there a difference? Yes but not one that is statistically different enough to make you notice. Thus the 1.7% comment. 

[aseibel]

On 10/27/2020 at 6:51 PM, Grumpy Bear said:

Biggest drag on winter mpg is....ready for this? Viscous drag.

Your explanation makes plenty of sense. I still wonder one thing. Lets say I'm making a 100 mile trip, each way.

Its 32 degrees in my garage when I start it. All the fluids and moving parts are cold, yes? A couple minutes in I'm getting warm air blown inside. By 5 country miles the engine reaches normal temp. I don't know at what point the bearing grease warms up. But at some point don't all the moving parts reach "normal" operating temp again?

 

So out of my 100 mile trip, the beginning 10-20 miles or so may be highly inefficient. But the remaining 80 are relatively normal, wouldn't you say? In my work car, the majority of my trips were long distance, so none of this 5 minute drive while never warming up stuff. I checked my tire pressure every 2 weeks, so no large drop in pressure.

 

It's shocking to me that taking a trip in January and burning a whole tank of fuel in 1 day, only 0.5 of the MPG drop is due to the fuel and the other 4.5 drop is because of the resistance of cold parts/lube.

[Grumpy Bear]

47 minutes ago, aseibel said:

Your explanation makes plenty of sense. I still wonder one thing. Lets say I'm making a 100 mile trip, each way.

Its 32 degrees in my garage when I start it. All the fluids and moving parts are cold, yes? A couple minutes in I'm getting warm air blown inside. By 5 country miles the engine reaches normal temp. I don't know at what point the bearing grease warms up. But at some point don't all the moving parts reach "normal" operating temp again?

 

So out of my 100 mile trip, the beginning 10-20 miles or so may be highly inefficient. But the remaining 80 are relatively normal, wouldn't you say? In my work car, the majority of my trips were long distance, so none of this 5 minute drive while never warming up stuff. I checked my tire pressure every 2 weeks, so no large drop in pressure.

 

It's shocking to me that taking a trip in January and burning a whole tank of fuel in 1 day, only 0.5 of the MPG drop is due to the fuel and the other 4.5 drop is because of the resistance of cold parts/lube.

Sad but true. 

 

It's a math thing.

 

I take ten test and score 100 on them. My average is 100. 

I score 100 on 8 test and don't show up for 2 my average is now 80

How many more test do I have to score 100 on to get back to just 90? Ten more perfect scores or 20 total test. 

95% requires a total of 40 test. 100% is impossible. 

 

I learned allot when I installed my Scan Gauge II. I put up water temperature, Oil temperature and transmission temperature them observer for a year logging miles to stabilize each. In the winter it is ridiculous how long it takes to reach operating temperature in the oils. In the summer my water is up to heat in 5 miles. In the winter about 7 miles. In the summer my oil is up to full temp in about 10 miles, in the winter 25 or more. The transmission which takes about 15-20 in the summer takes as long as an hour in the winter. Before I bypassed the trans stat and let some fluid be heated by the radiator it took 75 miles to reach 150 F and 100 miles to reach 190 F. 

Diff? Wheel bearings?

 

IF summer hot is running through water and cold is running through honey then winter cold is concrete. 

  

[aseibel]

11 minutes ago, Grumpy Bear said:

Sad but true. 

IF summer hot is running through water and cold is running through honey then winter cold is concrete. 

Then I'm sure glad I have an insulated attached garage. Even on those -10 degree mornings outside, usually the vehicle temp is around 30+ inside the garage. 

[Salsa De Piña]

Straight from the EPA, boys(https://www.fueleconomy.gov/feg/coldweather.shtml):

Why is winter fuel economy lower?

Cold weather affects your vehicle in more ways than you might expect:

• Engine and transmission friction increases in cold temperatures due to cold engine oil and other drive-line fluids.
• It takes longer for your engine to reach its most fuel-efficient temperature. This affects shorter trips more, since your car spends more of your trip at less-than-optimal temperatures.
• Heated seats, window defrosters, and heater fans use additional power.
• Warming up your vehicle before you start your trip lowers your fuel economy—idling gets 0 miles per gallon.
• Colder air is denser, increasing aerodynamic drag on your vehicle, especially at highway speeds.
• Tire pressure decreases in colder temperatures, increasing rolling resistance.
• Winter grades of gasoline can have slightly less energy per gallon than summer blends.
• Battery performance decreases in cold weather, making it harder for your alternator to keep your battery charged. This also affects the performance of the regenerative braking system on hybrids, plug-in hybrids, and electric vehicles.

In severe winter weather, your mpg can drop even further.

• Icy or snow-covered roads decrease your tires' grip on the road, wasting energy.
• Safe driving speeds on slick roads can be much lower than normal, further reducing fuel economy, especially at speeds below 30 to 40 mph.
• Using four-wheel drive uses more fuel.

[Grumpy Bear]

20 minutes ago, Salsa De Piña said:

Straight from the EPA, boys(https://www.fueleconomy.gov/feg/coldweather.shtml):

Why is winter fuel economy lower?

 

Well....since the EPA said it 

 

Wait...didn't I just say al that? 

Edited October 29, 2020 by Grumpy Bear

[Grumpy Bear]

On 10/27/2020 at 4:37 PM, aseibel said:

Grump

 

Fewer years, same pattern.

 

 

Edited October 29, 2020 by Grumpy Bear

[Salsa De Piña]

15 minutes ago, Grumpy Bear said:

Well....since the EPA said it 

 

Wait...didn't I just say al that? 

Oh, come on...  They're bound to have your best interests in mind once in a while.

 

The only one of these I somewhat disagree with is the tire pressure.  I keep mine in check (though more energy definitely goes into flexing the rubber.)  But then again, if my wife's car is any indication...