Surprising increase in truck MPG

I'd vote for the drivetrain getting broken in, with possibly an adjustment for seasonal changes and/or fuel formulations. I regularly get 400+ miles from a tank of gas in my car in the summer, but it drops to 325-350 in the winter. I blame increased use of the A/C (for defrost) and am curious if the difference between "summer gas" and "winter gas" contributes in any way.

nate

Also in the summer your oil viscosity will be down. I'd suspect the service station has been using a higher viscosity mineral oil. Don't think it's synthetic that makes the difference, I think its viscosity (at operating temperature). Synthetics hold their viscosity better as they warm up (which goes the "wrong" way).

Reply to
newshound
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That's possible, yes. Strange.

i
Reply to
Ignoramus15242

So, is "gasohol" really that much less energy dense???

i
Reply to
Ignoramus15242

RCM only

On Fri, 18 Apr 2008 09:52:27 -0700, with neither quill nor qualm, "T.Alan Kraus" quickly quoth:

Man, what are you _flying_? Or are you driving an Abrahms?

-- The only difference between a rut and a grave...is in their dimensions. -- Ellen Glasglow

Reply to
Larry Jaques

RCM only

On Fri, 18 Apr 2008 15:04:29 -0500, with neither quill nor qualm, Ignoramus15242 quickly quoth:

Yes, it is. I just realized why my mileage went from 14 down to 12.4. Oregon (Fred Meyer fuel stations in particular) just switched to gasohol between my first and second tankfuls. I noticed the same thing with my Ford in CA when filling at various stations, some with and some without ethanol. It was a 10% or more difference every time. The Ford pinged less on gasohol but, at these prices, I'd much prefer the real gas, TYVM.

-- The only difference between a rut and a grave...is in their dimensions. -- Ellen Glasglow

Reply to
Larry Jaques

In rec.crafts.metalworking Ignoramus15242 wrote: (snip)

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Gasoline is 9700 Wh/l Ethanol is 6100 Wh/l

So, from that, 10% ethanol gasoline is: 9340 Wh/l, so somewhere in the range of about 4% less energy dense.

Other oxygenates can have a better or worse effect than ethanol.

Reply to
Todd Rich

One thing that you can be sure of, synthetic oil did not result in this perceived increase. I have nothing against synthetics, but feel that they are oversold with respect to the miracles that are claimed for them.

After 18 months, you cannot hope to account for this level of increase because of engine "wearing in". Malarkey.

You are either not measuring the mileage accurately, OR you have a different gasoline mixture, OR your driving conditions are grossly different from previously.

I hope I could be wrong, but it is unlikely.

Reply to
HLS

Lubricants get thinner when it is warmer. Less energy loss. Less ethanol in the fuel will give better "mileage". Keep track of the # of miles and gallons for 10 tanks, then average them to see if you have a "real" difference, but don't change the way or the places you go if you want useful data. Is anybody else driving your vehicle? My wife gets about 6 mpg less than I do in the same car, going the same places. Are you always getting the fuel at the same place? No, not all fueling ramps are level, at least not where I go sometimes. This can make a gallon difference. The way you are measuring, you could simply have a change in the float of your fuel gage.

Pete Stanaitis

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Reply to
spaco

Where are you and what is the weather situation My 94 TransSpert gets almost double the mileage in the summer than what it gets in the winter - particularly around town. Also, the engine IS now broken in on yours (mine too - I've got

100,000km on the new rebuilt)
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Reply to
clare at snyder dot ontario do

Yes. If your fuel is 10% ethanol, it will have about 5% less energy than an equivalent volume of straight gasoline.

nate

Reply to
Nate Nagel

10% ethanol costs you 5% in power because ethanol has half the btu/gallon (roughly) of straight gasoline. If you know one fas is E10, and the other is E0 (straight gasoline) you are just as far ahead paying $4.20 a gallon of the E) as $4.00 per gallon for E10. ** Posted from
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Reply to
clare at snyder dot ontario do

I think that most likely, you are right.

i
Reply to
Ignoramus15242

RCM only

On Fri, 18 Apr 2008 21:56:31 -0400, with neither quill nor qualm, clare at snyder dot ontario dot canada quickly quoth:

That 5% power loss results in a 10-11.5% fuel economy decrease in both trucks I've driven with both fuels.

-- The only difference between a rut and a grave...is in their dimensions. -- Ellen Glasglow

Reply to
Larry Jaques

^^^^^^^^^^^^^^^^^^^^^^

exactly my point!

How is that a measure of anything useful? Assuming that you need

I have a watch, and the gas pump tells me how much gas I pumped

cheers T.Alan

Reply to
T.Alan Kraus

No just a '64 Spitfire, the one with four wheels. Consumes 1.2 gal/hour at whatever speed I choose to drive. Obviously the faster I drive the less time it takes, the less gas I use.

cheers T.Alan

Reply to
T.Alan Kraus

^^^^^^^^^^^^^^^^^^^ Oh, so you're talking about gallons per hour going INTO the tank. That's more of a property of the gas pump than the car.

Reply to
Leo Lichtman

"T.Alan Kraus" wrote: No just a '64 Spitfire, the one with four wheels. Consumes 1.2 gal/hour

^^^^^^^^^^^^^^^^^ How stupid of me! I didn't realize you were joking. You ARE joking, right?

Reply to
Leo Lichtman

On Fri, 18 Apr 2008 22:31:12 -0700, with neither quill nor qualm, "T.Alan Kraus" quickly quoth:

Condolences. I'm sure we'd all prefer the one with three wheels, though it gets _considerably_ worse gas mileage. I hear it's illegal to spew lead all over, as they're capable of, too.

So at 90mph, you get 75mpg? Excellent!

-- The only difference between a rut and a grave...is in their dimensions. -- Ellen Glasglow

Reply to
Larry Jaques

But that is a totally meaningless statement given that you are talking to a guy who is getting 10 miles per gallon which means he is throwing away (wasting) a lot more energy in every gallon of fuel than he is using.

Studies in fleet vehicles have consistently shown that adding 10% alcohol to gasoline INCREASES mpg by about 3 to 5 percent. It is also well known that the addition of alcohol to gasoline results in higher octane and in more complete combustion of the fuel than gasoline alone. Which explains why energy content calculations mean nothing.

However, The OP reports he was getting 10 mpg and it has recently increased to about 12 mpg - it is doubtful ethanol has much to do with his poor gas mileage. But if it does have anything to do with it - it is more likely the increase in mileage was due to gasohol not the other way around.

-jim

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Reply to
jim

Baloney. 10 MPG is a perfectly reasonable figure depending on the vehicle and what you are doing with it. If he was getting 10 MPG and it suddenly improved a couple MPG and his pickup isn't a 1 T heavy duty model then perhaps has has had a problem with a bad sensor connection or something that was hurting the mileage and that problem has cleared itself. 10 MPG isn't unreasonable for a 1 T dually with a big block hauling stuff around, but if it's a 1/2 T SRW under ordinary use it should do a bit better than that. Perhaps Iggy can post the detail on the truck, including axle ratio so others can give him and idea of what he should be getting for MPG and he can see if his MPG is in the expected range.

Reply to
Pete C.

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