Drop in MPGs
Thread Starter
JK Enthusiast
Joined: Apr 2011
Posts: 392
Likes: 0
From: Upstate NY
Do they have to post that on the pump? I always see a sticker on the pump but if my memory serves me right, I think it said it may contain up to 10% ethanol.
JK Enthusiast
Joined: Nov 2012
Posts: 302
Likes: 0
From: Weatherford, OK
I have seen both ways, not sure what the law is, In TX they used to post it, then all stickers went away but the ethanol was still in use. Now in OK, and very few places even sale ethanol gas.
JK Jedi Master
Joined: Feb 2008
Posts: 12,907
Likes: 185
From: Maine
Regarding the government's screwing with our gas...
I blame them for mandating ethanol.
I'm glad they don't allow winter blend to be sold all year 'round. Refineries have to be back on summer blend by June each year.
I'm glad they don't screw with the price like they do in Europe, where it's about $8 per gallon.
Thread Starter
JK Enthusiast
Joined: Apr 2011
Posts: 392
Likes: 0
From: Upstate NY
Yes, it has to be listed on the pump. (At least in Maine, they do.)
Regarding the government's screwing with our gas...
I blame them for mandating ethanol.
I'm glad they don't allow winter blend to be sold all year 'round. Refineries have to be back on summer blend by June each year.
I'm glad they don't screw with the price like they do in Europe, where it's about $8 per gallon.
Regarding the government's screwing with our gas...
I blame them for mandating ethanol.
I'm glad they don't allow winter blend to be sold all year 'round. Refineries have to be back on summer blend by June each year.
I'm glad they don't screw with the price like they do in Europe, where it's about $8 per gallon.
JK Enthusiast
Joined: Jan 2010
Posts: 202
Likes: 1
From: New Brunswick
Up in my parts here in Canada we have the "winter" gas all year around now.. it sucks..
Some stations are running a 91 octane that is clean. I just got a superchips last month so next fill I'm going to try it out to see if I notice a difference..
Obviously there shouldn't be a cost savings because of the cost of 91 octane but I'm doing it more just to see..
Some stations are running a 91 octane that is clean. I just got a superchips last month so next fill I'm going to try it out to see if I notice a difference..
Obviously there shouldn't be a cost savings because of the cost of 91 octane but I'm doing it more just to see..
JK Freak
Joined: Oct 2012
Posts: 832
Likes: 1
From: Sabina, OH
There might be more to it...
My daily driver is a Mazda 3. I was averaging around 34-36 MPG with spirited driving. Now I am driving like a senior citizen to get 32. We just got our JK so I don't have enough history to know if there has been a change. That said, we are not getting what I expected. My wife drives it about 20 miles each day on the interstate. She is averaging about 16. It is still completely stock.
While I am aware that there are different additives for fuel in summer vs. winter, the octane level shouldn't change, and therefor the efficiency of the engine shouldn't change either. (Provided you aren't getting an ethanol mix, which isn't likely this time of year) Some other things to consider that are likely at play here are; longer engine warming times, Increased air volume due to temperature, and decreased tire pressure.
The first "longer engine warming times". While new engines don't require a choke, they do require a different ratio of fuel to air to run at cold temperatures. To accomplish this there is an air intake temperature senor. The computer lengthens the fuel injector pulse width to increase the ratio. (Your old choke used to restrict the air to accomplish the same thing.) Once the engine gets warm pulse with returns to a more normal length. "Have you ever noticed the smell of fuel coming out of your tailpipe when you just start your engine? That's cuz it's running VERY rich." The colder the temperatures outside the longer you run in this condition.
The second point "Increased air volume" is more of a physics thing. As air gets colder the molecules get smaller. So more molecules get into the cylinder given the same valve timing. Other than at warm-up, your engine is trying to keep a 14:1 ratio or air to fuel. The computer does its best guess at how much fuel is needed my measuring the intake volume (Mass-airflow switch). Then, it checks how well it is doing by reading the O2 sensor in the exhaust and makes adjustments as needed. So when the air is cold you use more fuel because you are sucking in more air. Now, in theory, you should see an increase in power and not need to push the pedal so darn hard. But most of us are pretty habitual drivers and push the same amount and don't realize we are accelerating marginally faster.
I commented earlier that it isn't likely you will find ethanol this time of year. This is because it requires different combustion temperatures than gas and doesn't work well in the colder weather. Additionally, US corn production is lower this time of year and it is the most common source of ethanol. (Especially this year as production was low as a result of the drought.)
My last point "lower tire pressure" is physics too. It is a result of the smaller air molecules. High volume tires will loose several PSI for every 20 degree drop in air pressure. In addition the smaller molecules leak easier. "Remember the tire discounter's Nitrogen commercials" Nitrogen has larger molecules and is more stable in temperature changes. But we jeep freaks are always tweaking our tire pressures so Nitrogen isn't very practical. The bottom-line is you might be rolling on lower tire pressure than you intend, and it's increasing your drag.
No "Smiking-Gun" here but some other ideas for what could be going on.... By the way I'm not an expert, but I did stay at a Holiday-Inn express last night
While I am aware that there are different additives for fuel in summer vs. winter, the octane level shouldn't change, and therefor the efficiency of the engine shouldn't change either. (Provided you aren't getting an ethanol mix, which isn't likely this time of year) Some other things to consider that are likely at play here are; longer engine warming times, Increased air volume due to temperature, and decreased tire pressure.
The first "longer engine warming times". While new engines don't require a choke, they do require a different ratio of fuel to air to run at cold temperatures. To accomplish this there is an air intake temperature senor. The computer lengthens the fuel injector pulse width to increase the ratio. (Your old choke used to restrict the air to accomplish the same thing.) Once the engine gets warm pulse with returns to a more normal length. "Have you ever noticed the smell of fuel coming out of your tailpipe when you just start your engine? That's cuz it's running VERY rich." The colder the temperatures outside the longer you run in this condition.
The second point "Increased air volume" is more of a physics thing. As air gets colder the molecules get smaller. So more molecules get into the cylinder given the same valve timing. Other than at warm-up, your engine is trying to keep a 14:1 ratio or air to fuel. The computer does its best guess at how much fuel is needed my measuring the intake volume (Mass-airflow switch). Then, it checks how well it is doing by reading the O2 sensor in the exhaust and makes adjustments as needed. So when the air is cold you use more fuel because you are sucking in more air. Now, in theory, you should see an increase in power and not need to push the pedal so darn hard. But most of us are pretty habitual drivers and push the same amount and don't realize we are accelerating marginally faster.
I commented earlier that it isn't likely you will find ethanol this time of year. This is because it requires different combustion temperatures than gas and doesn't work well in the colder weather. Additionally, US corn production is lower this time of year and it is the most common source of ethanol. (Especially this year as production was low as a result of the drought.)
My last point "lower tire pressure" is physics too. It is a result of the smaller air molecules. High volume tires will loose several PSI for every 20 degree drop in air pressure. In addition the smaller molecules leak easier. "Remember the tire discounter's Nitrogen commercials" Nitrogen has larger molecules and is more stable in temperature changes. But we jeep freaks are always tweaking our tire pressures so Nitrogen isn't very practical. The bottom-line is you might be rolling on lower tire pressure than you intend, and it's increasing your drag.
No "Smiking-Gun" here but some other ideas for what could be going on.... By the way I'm not an expert, but I did stay at a Holiday-Inn express last night
JK Enthusiast
Joined: Jul 2012
Posts: 406
Likes: 1
From: Guelph, ON
My daily driver is a Mazda 3. I was averaging around 34-36 MPG with spirited driving. Now I am driving like a senior citizen to get 32. We just got our JK so I don't have enough history to know if there has been a change. That said, we are not getting what I expected. My wife drives it about 20 miles each day on the interstate. She is averaging about 16. It is still completely stock.
While I am aware that there are different additives for fuel in summer vs. winter, the octane level shouldn't change, and therefor the efficiency of the engine shouldn't change either. (Provided you aren't getting an ethanol mix, which isn't likely this time of year) Some other things to consider that are likely at play here are; longer engine warming times, Increased air volume due to temperature, and decreased tire pressure.
The first "longer engine warming times". While new engines don't require a choke, they do require a different ratio of fuel to air to run at cold temperatures. To accomplish this there is an air intake temperature senor. The computer lengthens the fuel injector pulse width to increase the ratio. (Your old choke used to restrict the air to accomplish the same thing.) Once the engine gets warm pulse with returns to a more normal length. "Have you ever noticed the smell of fuel coming out of your tailpipe when you just start your engine? That's cuz it's running VERY rich." The colder the temperatures outside the longer you run in this condition.
The second point "Increased air volume" is more of a physics thing. As air gets colder the molecules get smaller. So more molecules get into the cylinder given the same valve timing. Other than at warm-up, your engine is trying to keep a 14:1 ratio or air to fuel. The computer does its best guess at how much fuel is needed my measuring the intake volume (Mass-airflow switch). Then, it checks how well it is doing by reading the O2 sensor in the exhaust and makes adjustments as needed. So when the air is cold you use more fuel because you are sucking in more air. Now, in theory, you should see an increase in power and not need to push the pedal so darn hard. But most of us are pretty habitual drivers and push the same amount and don't realize we are accelerating marginally faster.
I commented earlier that it isn't likely you will find ethanol this time of year. This is because it requires different combustion temperatures than gas and doesn't work well in the colder weather. Additionally, US corn production is lower this time of year and it is the most common source of ethanol. (Especially this year as production was low as a result of the drought.)
My last point "lower tire pressure" is physics too. It is a result of the smaller air molecules. High volume tires will loose several PSI for every 20 degree drop in air pressure. In addition the smaller molecules leak easier. "Remember the tire discounter's Nitrogen commercials" Nitrogen has larger molecules and is more stable in temperature changes. But we jeep freaks are always tweaking our tire pressures so Nitrogen isn't very practical. The bottom-line is you might be rolling on lower tire pressure than you intend, and it's increasing your drag.
No "Smiking-Gun" here but some other ideas for what could be going on.... By the way I'm not an expert, but I did stay at a Holiday-Inn express last night
While I am aware that there are different additives for fuel in summer vs. winter, the octane level shouldn't change, and therefor the efficiency of the engine shouldn't change either. (Provided you aren't getting an ethanol mix, which isn't likely this time of year) Some other things to consider that are likely at play here are; longer engine warming times, Increased air volume due to temperature, and decreased tire pressure.
The first "longer engine warming times". While new engines don't require a choke, they do require a different ratio of fuel to air to run at cold temperatures. To accomplish this there is an air intake temperature senor. The computer lengthens the fuel injector pulse width to increase the ratio. (Your old choke used to restrict the air to accomplish the same thing.) Once the engine gets warm pulse with returns to a more normal length. "Have you ever noticed the smell of fuel coming out of your tailpipe when you just start your engine? That's cuz it's running VERY rich." The colder the temperatures outside the longer you run in this condition.
The second point "Increased air volume" is more of a physics thing. As air gets colder the molecules get smaller. So more molecules get into the cylinder given the same valve timing. Other than at warm-up, your engine is trying to keep a 14:1 ratio or air to fuel. The computer does its best guess at how much fuel is needed my measuring the intake volume (Mass-airflow switch). Then, it checks how well it is doing by reading the O2 sensor in the exhaust and makes adjustments as needed. So when the air is cold you use more fuel because you are sucking in more air. Now, in theory, you should see an increase in power and not need to push the pedal so darn hard. But most of us are pretty habitual drivers and push the same amount and don't realize we are accelerating marginally faster.
I commented earlier that it isn't likely you will find ethanol this time of year. This is because it requires different combustion temperatures than gas and doesn't work well in the colder weather. Additionally, US corn production is lower this time of year and it is the most common source of ethanol. (Especially this year as production was low as a result of the drought.)
My last point "lower tire pressure" is physics too. It is a result of the smaller air molecules. High volume tires will loose several PSI for every 20 degree drop in air pressure. In addition the smaller molecules leak easier. "Remember the tire discounter's Nitrogen commercials" Nitrogen has larger molecules and is more stable in temperature changes. But we jeep freaks are always tweaking our tire pressures so Nitrogen isn't very practical. The bottom-line is you might be rolling on lower tire pressure than you intend, and it's increasing your drag.
No "Smiking-Gun" here but some other ideas for what could be going on.... By the way I'm not an expert, but I did stay at a Holiday-Inn express last night
All things equal, the added warm up time will definitely affect your mpg. I'm pretty well stock and was averaging 22, now i'm down to 21 just on the warm up... I'm in Canada also so we have winter blends all the time...
JK Newbie
Joined: Apr 2012
Posts: 62
Likes: 0
From: Tucson, AZ
