Towing and MPG
Thread Starter
|
Member
Joined: Oct 2006
Posts: 38
Likes: 0
From: BOSTON
Towing and MPG
I know that it is normal for the fuel efficiency to decrease while towing. But is it normal for the fuel effiiceincy to stay low after you tow? Before I towed my 7000lb camper 150 miles I was getting 14 MPG and now months later I can't seem to get above 12 MPG. Tires have enough pressure and nothing seems to be broken. I hope something isn't wrong with the transmission. I thought I would ask you before I brought it to a mechanic.
Thank you.
Thank you.
Senior Member
Joined: Mar 2001
Posts: 4,506
Likes: 6
From: Puyallup, WA
That's really strange indeed.... My first thought was that you were calculating the MPG on the same tank of gas from towing and not towing, but since you say it's been 'months', I'm sure you've filled up since then and not towed!
My truck seems to do really well after towing! I mean, the computer 'learns' and adapts to the towing condition and when it's not towing, it's still kinda using it's settings and it feels real peppy and the mpg's are back to it's 'normal' range immediately.
You might try simply 'resetting' your computer on the truck by disconnecting the battery for about 15 minutes and letting it 'learn' it's way all over again??
Good luck!
Mitch
My truck seems to do really well after towing! I mean, the computer 'learns' and adapts to the towing condition and when it's not towing, it's still kinda using it's settings and it feels real peppy and the mpg's are back to it's 'normal' range immediately.
You might try simply 'resetting' your computer on the truck by disconnecting the battery for about 15 minutes and letting it 'learn' it's way all over again??
Good luck!
Mitch
Member
Joined: Aug 2008
Posts: 69
Likes: 0
From: Minden, NV
x3!
Warning! Nerd information from theoildrum.com on gasoline blends follows.
"Gasoline is composed of many different hydrocarbons. Crude oil enters a refinery, and is processed through various units before being blended into gasoline. A refinery may have a fluid catalytic cracker (FCC), an alkylate unit, and a reformer, each of which produces gasoline blending components. Alkylate gasoline, for example, is valuable because it has a very high octane, and can be used to produce high-octane (and higher value) blends. Light straight run gasoline is the least processed stream. It is cheap to produce, but it has a low octane. The person specifying the gasoline blends has to mix all of the components together to meet the product specifications.
There are two very important (although not the only) specifications that need to be met for each gasoline blend. The gasoline needs to have the proper octane, and it needs to have the proper Reid vapor pressure, or RVP. While the octane of a particular grade is constant throughout the year, the RVP spec changes as cooler weather sets in.
The RVP is the vapor pressure of the gasoline blend when the temperature is 100 degrees F. Normal atmospheric pressure varies, but is usually around 14.7 lbs per square inch (psi). Atmospheric pressure is caused by the weight of the air over our heads. If a liquid has a vapor pressure of greater than local atmospheric pressure, that liquid boils. For example, when you heat a pot of water, the vapor pressure increases until it reaches atmospheric pressure. At that point, the water begins to boil.
In the summer, when temperatures can exceed 100 degrees F in many locations, it is important that the RVP of gasoline is well below 14.7. Otherwise, it can pressure up your gas tanks and gas cans, and it can boil in open containers. Gas that is boiled off ends up in the atmosphere, and contributes to air pollution. Therefore, the EPA has declared that summer gasoline blends may not exceed 7.8 psi in some locations, and 9.0 psi in others.
A typical summer gasoline blend might consist of 40% FCC gas, 25% straight run gas, 15% alkylate, 18% reformate, and 2% butane. The RVP of the gasoline blend depends on how much of each component is in the blend, and what the RVP is of each component. Butane is a relatively inexpensive ingredient in gasoline, but it has the highest vapor pressure at around 52 psi.
In a gasoline blend, each component contributes a fraction to the overall RVP. In the case of butane, if there is 10% butane in the blend, it will contribute around 5.2 psi (10% of 52 psi) to the overall blend. (In reality, it is slightly more complicated than this, because some components interact with each other which can affect the expected RVP). This means that in the summer, the butane fraction must be very low in the gasoline, or the overall RVP of the blend will be too high. That is the primary difference between winter and summer gasoline blends."
Warning! Nerd information from theoildrum.com on gasoline blends follows. "Gasoline is composed of many different hydrocarbons. Crude oil enters a refinery, and is processed through various units before being blended into gasoline. A refinery may have a fluid catalytic cracker (FCC), an alkylate unit, and a reformer, each of which produces gasoline blending components. Alkylate gasoline, for example, is valuable because it has a very high octane, and can be used to produce high-octane (and higher value) blends. Light straight run gasoline is the least processed stream. It is cheap to produce, but it has a low octane. The person specifying the gasoline blends has to mix all of the components together to meet the product specifications.
There are two very important (although not the only) specifications that need to be met for each gasoline blend. The gasoline needs to have the proper octane, and it needs to have the proper Reid vapor pressure, or RVP. While the octane of a particular grade is constant throughout the year, the RVP spec changes as cooler weather sets in.
The RVP is the vapor pressure of the gasoline blend when the temperature is 100 degrees F. Normal atmospheric pressure varies, but is usually around 14.7 lbs per square inch (psi). Atmospheric pressure is caused by the weight of the air over our heads. If a liquid has a vapor pressure of greater than local atmospheric pressure, that liquid boils. For example, when you heat a pot of water, the vapor pressure increases until it reaches atmospheric pressure. At that point, the water begins to boil.
In the summer, when temperatures can exceed 100 degrees F in many locations, it is important that the RVP of gasoline is well below 14.7. Otherwise, it can pressure up your gas tanks and gas cans, and it can boil in open containers. Gas that is boiled off ends up in the atmosphere, and contributes to air pollution. Therefore, the EPA has declared that summer gasoline blends may not exceed 7.8 psi in some locations, and 9.0 psi in others.
A typical summer gasoline blend might consist of 40% FCC gas, 25% straight run gas, 15% alkylate, 18% reformate, and 2% butane. The RVP of the gasoline blend depends on how much of each component is in the blend, and what the RVP is of each component. Butane is a relatively inexpensive ingredient in gasoline, but it has the highest vapor pressure at around 52 psi.
In a gasoline blend, each component contributes a fraction to the overall RVP. In the case of butane, if there is 10% butane in the blend, it will contribute around 5.2 psi (10% of 52 psi) to the overall blend. (In reality, it is slightly more complicated than this, because some components interact with each other which can affect the expected RVP). This means that in the summer, the butane fraction must be very low in the gasoline, or the overall RVP of the blend will be too high. That is the primary difference between winter and summer gasoline blends."
Thread Starter
|
Member
Joined: Oct 2006
Posts: 38
Likes: 0
From: BOSTON
Thanks for the responses. I will try disconnecting the battery to see if this helps.
I never heard about the winter fuel formula. This is good information. Does this mean that all ford trucks have lower fuel efficiency in the colder regions during the winter?
I never heard about the winter fuel formula. This is good information. Does this mean that all ford trucks have lower fuel efficiency in the colder regions during the winter?