Surprising increase in truck MPG

I have a Chevy Silverado pickup that is by now about 18 months old.

I was never able to get more that about 220 miles out of a 22 gallon
tank of gas, sometimes even less.

However, the last three refills, gave me 280, 266, and 283 miles per
refill. (I usually run until my tanks gets fully empty, since I have
an emergency gas canister for the instance when I run out of gas).

This represents approximately 22% increase in MPG that I have hard
times explaining. I see three possible explanations.

1) Just before those refills, I did an oil change and used Mobil 1
synthetic oil. The previous oil changes were at a service station.

2) The engine had a chance to "burn in" and naturally improved its
efficiency

3) something is seriously mistaken in my measurements.

I am at a loss and am very puzzled. Can synthetic oil really account
for that much of an increase? I highly doubt it.

i

"Ignoramus15242" > wrote in message
...
>I have a Chevy Silverado pickup that is by now about 18 months old.
>
> I was never able to get more that about 220 miles out of a 22 gallon
> tank of gas, sometimes even less.
>
> However, the last three refills, gave me 280, 266, and 283 miles per
> refill. (I usually run until my tanks gets fully empty, since I have
> an emergency gas canister for the instance when I run out of gas).
>
> This represents approximately 22% increase in MPG that I have hard
> times explaining. I see three possible explanations.
>
> 1) Just before those refills, I did an oil change and used Mobil 1
> synthetic oil. The previous oil changes were at a service station.
>
> 2) The engine had a chance to "burn in" and naturally improved its
> efficiency
>
> 3) something is seriously mistaken in my measurements.
>
> I am at a loss and am very puzzled. Can synthetic oil really account
> for that much of an increase? I highly doubt it.
>
> i

Mobil itself claims only a 2% improvement in fuel economy, with comparable
oil weight. My experience is somewhat better, but, like you, I can't really
account for break-in and so on.

I use Mobil 1 5W-20 in my Ford Focus, and I intend to stick with it.

--
Ed Huntress

On 2008-04-18, Ed Huntress > wrote:
>
> "Ignoramus15242" > wrote in message
> ...
>>I have a Chevy Silverado pickup that is by now about 18 months old.
>>
>> I was never able to get more that about 220 miles out of a 22 gallon
>> tank of gas, sometimes even less.
>>
>> However, the last three refills, gave me 280, 266, and 283 miles per
>> refill. (I usually run until my tanks gets fully empty, since I have
>> an emergency gas canister for the instance when I run out of gas).
>>
>> This represents approximately 22% increase in MPG that I have hard
>> times explaining. I see three possible explanations.
>>
>> 1) Just before those refills, I did an oil change and used Mobil 1
>> synthetic oil. The previous oil changes were at a service station.
>>
>> 2) The engine had a chance to "burn in" and naturally improved its
>> efficiency
>>
>> 3) something is seriously mistaken in my measurements.
>>
>> I am at a loss and am very puzzled. Can synthetic oil really account
>> for that much of an increase? I highly doubt it.
>>
>> i
>
> Mobil itself claims only a 2% improvement in fuel economy, with comparable
> oil weight. My experience is somewhat better, but, like you, I can't really
> account for break-in and so on.
>
> I use Mobil 1 5W-20 in my Ford Focus, and I intend to stick with it.
>

For the next oil change, I may use regular cheap oil to see if there
is any difference.

i

Ignoramus15242 wrote:
> On 2008-04-18, Ed Huntress > wrote:
>>
>> "Ignoramus15242" > wrote in
>> message ...
>>> I have a Chevy Silverado pickup that is by now about 18 months old.
>>>
>>> I was never able to get more that about 220 miles out of a 22 gallon
>>> tank of gas, sometimes even less.
>>>
>>> However, the last three refills, gave me 280, 266, and 283 miles per
>>> refill. (I usually run until my tanks gets fully empty, since I have
>>> an emergency gas canister for the instance when I run out of gas).
>>>
>>> This represents approximately 22% increase in MPG that I have hard
>>> times explaining. I see three possible explanations.
>>>
>>> 1) Just before those refills, I did an oil change and used Mobil 1
>>> synthetic oil. The previous oil changes were at a service station.
>>>
>>> 2) The engine had a chance to "burn in" and naturally improved its
>>> efficiency
>>>
>>> 3) something is seriously mistaken in my measurements.
>>>
>>> I am at a loss and am very puzzled. Can synthetic oil really account
>>> for that much of an increase? I highly doubt it.
>>>
>>> i
>>
>> Mobil itself claims only a 2% improvement in fuel economy, with
>> comparable oil weight. My experience is somewhat better, but, like
>> you, I can't really account for break-in and so on.
>>
>> I use Mobil 1 5W-20 in my Ford Focus, and I intend to stick with it.
>>
>
> For the next oil change, I may use regular cheap oil to see if there
> is any difference.

Has the mix between Highway and City driving changed much?

You might also not want to run your tank down so far.
Electric fuel pumps that are in the tank last a lot longer if you keep them
well submerged.
Just a thought.


--

John R. Carroll
www.machiningsolution.com

Ignoramus15242 wrote:
> I have a Chevy Silverado pickup that is by now about 18 months old.
>
> I was never able to get more that about 220 miles out of a 22 gallon
> tank of gas, sometimes even less.
>
> However, the last three refills, gave me 280, 266, and 283 miles per
> refill. (I usually run until my tanks gets fully empty, since I have
> an emergency gas canister for the instance when I run out of gas).
>
> This represents approximately 22% increase in MPG that I have hard
> times explaining. I see three possible explanations.
>
> 1) Just before those refills, I did an oil change and used Mobil 1
> synthetic oil. The previous oil changes were at a service station.
>
> 2) The engine had a chance to "burn in" and naturally improved its
> efficiency
>
> 3) something is seriously mistaken in my measurements.

There you go.

You have to use 'miles' to find 'miles per gallon', not the fuel gauge.
Voltage differences, temperature, the tilt of the road and lots of other
things make the fuel gauge nothing anyone should think of as 'accurate'.

You check the odometer when you fill up. On your next fill, no matter
if even a half a tank, you check the miles on the odometer again. This
gives you the number of miles traveled and the amount of gas used to do
so. Then you just divide the miles by how many gallons used.

>
> I am at a loss and am very puzzled. Can synthetic oil really account
> for that much of an increase? I highly doubt it.
>
> i

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
'New' frame in the works for '08. Some Canadian Bush Trip and Build
Photos: http://mikeromainjeeptrips.shutterfly.com

On 2008-04-18, Mike Romain > wrote:
> Ignoramus15242 wrote:
>> I have a Chevy Silverado pickup that is by now about 18 months old.
>>
>> I was never able to get more that about 220 miles out of a 22 gallon
>> tank of gas, sometimes even less.
>>
>> However, the last three refills, gave me 280, 266, and 283 miles per
>> refill. (I usually run until my tanks gets fully empty, since I have
>> an emergency gas canister for the instance when I run out of gas).
>>
>> This represents approximately 22% increase in MPG that I have hard
>> times explaining. I see three possible explanations.
>>
>> 1) Just before those refills, I did an oil change and used Mobil 1
>> synthetic oil. The previous oil changes were at a service station.
>>
>> 2) The engine had a chance to "burn in" and naturally improved its
>> efficiency
>>
>> 3) something is seriously mistaken in my measurements.
>
> There you go.
>
> You have to use 'miles' to find 'miles per gallon', not the fuel gauge.
> Voltage differences, temperature, the tilt of the road and lots of other
> things make the fuel gauge nothing anyone should think of as 'accurate'.
>
> You check the odometer when you fill up. On your next fill, no matter
> if even a half a tank, you check the miles on the odometer again. This
> gives you the number of miles traveled and the amount of gas used to do
> so. Then you just divide the miles by how many gallons used.

Mike, the gallons used number was rather consistent.

Otherwise your idea is very good.

i

>>
>> I am at a loss and am very puzzled. Can synthetic oil really account
>> for that much of an increase? I highly doubt it.
>>
>> i
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 'New' frame in the works for '08. Some Canadian Bush Trip and Build
> Photos: http://mikeromainjeeptrips.shutterfly.com

Ignoramus15242 wrote:

> I have a Chevy Silverado pickup that is by now about 18 months old.
>
> I was never able to get more that about 220 miles out of a 22 gallon
> tank of gas, sometimes even less.
>
> However, the last three refills, gave me 280, 266, and 283 miles per
> refill. (I usually run until my tanks gets fully empty, since I have
> an emergency gas canister for the instance when I run out of gas).
>
> This represents approximately 22% increase in MPG that I have hard
> times explaining. I see three possible explanations.
>
> 1) Just before those refills, I did an oil change and used Mobil 1
> synthetic oil. The previous oil changes were at a service station.
>
> 2) The engine had a chance to "burn in" and naturally improved its
> efficiency
>
> 3) something is seriously mistaken in my measurements.
>
> I am at a loss and am very puzzled. Can synthetic oil really account
> for that much of an increase? I highly doubt it.
>
> i


I'm going to take a wild guess - that traffic is running a bit slower.


Richard
--
(remove the X to email)

Now just why the HELL do I have to press 1 for English?
John Wayne

In article > , cavelamb himself wrote:
>Ignoramus15242 wrote:
>
>> I have a Chevy Silverado pickup that is by now about 18 months old.
>>
>> I was never able to get more that about 220 miles out of a 22 gallon
>> tank of gas, sometimes even less.
>>
>> However, the last three refills, gave me 280, 266, and 283 miles per
>> refill. (I usually run until my tanks gets fully empty, since I have
>> an emergency gas canister for the instance when I run out of gas).
>>
>> This represents approximately 22% increase in MPG that I have hard
>> times explaining. I see three possible explanations.
>>
>> 1) Just before those refills, I did an oil change and used Mobil 1
>> synthetic oil. The previous oil changes were at a service station.
>>
>> 2) The engine had a chance to "burn in" and naturally improved its
>> efficiency
>>
>> 3) something is seriously mistaken in my measurements.
>>
>> I am at a loss and am very puzzled. Can synthetic oil really account
>> for that much of an increase? I highly doubt it.
>>
>> i
>
>
>I'm going to take a wild guess - that traffic is running a bit slower.

traffic congestion drives down MPG for most vehicles. It would be rather
rare that it would result in a steady speed that was better for his
truck.

Ignoramus15242 wrote:
> On 2008-04-18, Mike Romain > wrote:
>> Ignoramus15242 wrote:
>>> I have a Chevy Silverado pickup that is by now about 18 months old.
>>>
>>> I was never able to get more that about 220 miles out of a 22 gallon
>>> tank of gas, sometimes even less.
>>>
>>> However, the last three refills, gave me 280, 266, and 283 miles per
>>> refill. (I usually run until my tanks gets fully empty, since I have
>>> an emergency gas canister for the instance when I run out of gas).
>>>
>>> This represents approximately 22% increase in MPG that I have hard
>>> times explaining. I see three possible explanations.
>>>
>>> 1) Just before those refills, I did an oil change and used Mobil 1
>>> synthetic oil. The previous oil changes were at a service station.
>>>
>>> 2) The engine had a chance to "burn in" and naturally improved its
>>> efficiency
>>>
>>> 3) something is seriously mistaken in my measurements.
>> There you go.
>>
>> You have to use 'miles' to find 'miles per gallon', not the fuel gauge.
>> Voltage differences, temperature, the tilt of the road and lots of other
>> things make the fuel gauge nothing anyone should think of as 'accurate'.
>>
>> You check the odometer when you fill up. On your next fill, no matter
>> if even a half a tank, you check the miles on the odometer again. This
>> gives you the number of miles traveled and the amount of gas used to do
>> so. Then you just divide the miles by how many gallons used.
>
> Mike, the gallons used number was rather consistent.
>
> Otherwise your idea is very good.
>
> i

Consistent enough to be off 16 miles or +/- 5%. For a fuel gauge, this
is wickedly accurate or your eye on the line is.

Even a head wind vs a tail wind can account for 5% mileage difference
when actually measured by the 'miles' driven.


>> Mike
>> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> 'New' frame in the works for '08. Some Canadian Bush Trip and Build
>> Photos: http://mikeromainjeeptrips.shutterfly.com

I would recommend you do not run until the tank is completely
empty. The high pressure EFI fuel pump really doesn't like that.