Any one else noticing decreased gas mileage on their vehicles lately - Page 2

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[ARCHIVED THREAD] - Any one else noticing decreased gas mileage on their vehicles lately (Page 2 of 2)

Posted: 6/7/2008 10:26:07 AM EDT

[#1]

Quoted:

Quoted:

To the people who record the number of miles between fill ups and calculate that way..

Again not accurate. There are far too many variables for you to even come close to 10% accuracy. Just not going to happen!

How is that not relatively accurate? Assuming that your tire/wheel size is factory, and you fill up to the same level every time. Are you saying that odometers are less than 90% accurate?

I can see how there would be some error, but how would it not even be able to "come close to 10% accuracy"?

There are just too many variables to account for.
Your driving habits play the biggest role. These is no way you can match your style of driving to a point where you can blame a 10% loss on the gasoline you buy. Just because you lost 10, 20% MPG doesn't mean its the gas.

How do you know it's the same level every time?

Even if you go by the pump the daily changes in specific gravity of the gasoline you a pumping.

Is the e-vap system on the car purged? Is it full of fuel because you topped off a little much?

I am not saying you can not notice a 10% loss in MPG. I am saying there is no way to blame it on the fuel without very controlled settings.

When comparing tank to tank this is true but when you compare stats on lots of fill ups it does a lot to generalize those variables.

Posted: 6/7/2008 10:27:23 AM EDT

[#2]

Quoted:
Maybe they are adding water or some other shit to the gas. At current prices it wouldn't surprise me a bit. Make sure you got your tires inflated right, clean air filter and keep your speed around 60 on the highway to get max mileage.

And that is where conspiracies are born.

Many things affect mileage. Check tires, air filters etc.

Then realize gasoline isn't a consistent product, there is a range of densities, temperatures and the like.

Then there is weather. Warmer weather drops efficiency a bit as it too is less dense and the "sink" is at a higher temperature.

Then there is the air conditioning load.

Ethanol use should be limited in the summer blends mandated from June 15 until September. Only E85 should have appreciable ethanol in it.

Posted: 6/7/2008 10:28:44 AM EDT

[#3]

That always happens when the weather warms up, because gasoline becomes less dense (i.e. a gallon weighs less in summer than in winter).

Posted: 6/7/2008 10:29:42 AM EDT

[#4]

Quoted:

Quoted:
It's the Ethanol.
Buy Premium gas, it doesn't have Ethanol, at least around here it doesn't.

Just an FYI. I buy Premium gas and the pump is marked 10% Ethanol. That's in PA.

My 1998 Nissan Pathfinder gets better mileage on 87 octane gas than it does on 89 or 91.

Posted: 6/7/2008 10:40:43 AM EDT

[#5]

Quoted:

Quoted:

To the people who record the number of miles between fill ups and calculate that way..

Again not accurate. There are far too many variables for you to even come close to 10% accuracy. Just not going to happen!

How is that not relatively accurate? Assuming that your tire/wheel size is factory, and you fill up to the same level every time. Are you saying that odometers are less than 90% accurate?

I can see how there would be some error, but how would it not even be able to "come close to 10% accuracy"?

There are just too many variables to account for.
Your driving habits play the biggest role. These is no way you can match your style of driving to a point where you can blame a 10% loss on the gasoline you buy. Just because you lost 10, 20% MPG doesn't mean its the gas.

How do you know it's the same level every time?

Even if you go by the pump the daily changes in specific gravity of the gasoline you a pumping.

Is the e-vap system on the car purged? Is it full of fuel because you topped off a little much?

I am not saying you can not notice a 10% loss in MPG. I am saying there is no way to blame it on the fuel without very controlled settings.

Oh - I get what you are saying.

I misunderstood. I thought you were saying that it was impossible to measure your MPG by basing it on aggregations of odometer readings and gas fillups over time.

I was trying to say that I believe I can get a reasonably accurate measure of my overall MPG (say over the span of a year) - by dividing mileage by gas fillup - to describe the overall average MPG that I am consuming given my mix of driving conditions. While stuff like changes in density and other small variations would obviously introduce error, I'd bet that error would still be within 10%.

Now that I UNDERSTAND you are saying that it would be impossible to detect a 10% difference between one type of gas and another type of gas (especially in a relatively short time span which people seem to be talking about), using that method, I would tend to agree. I completely agree that very controlled setting are needed to really be drawing conclusions.

Sorry I misunderstood what you were talking about.

Posted: 6/7/2008 10:42:53 AM EDT

[#6]

Quoted:

Quoted:
It's the Ethanol.
Buy Premium gas, it doesn't have Ethanol, at least around here it doesn't.

Just an FYI. I buy Premium gas and the pump is marked 10% Ethanol. That's in PA.

My 1998 Nissan Pathfinder gets better mileage on 87 octane gas than it does on 89 or 91.

Because thats what it was made to use. Using anything other than what your car was designed for is a waste of money.

Posted: 6/7/2008 10:43:57 AM EDT

[#7]

Quoted:
My POS explorer is still getting 18 in the city.

I drive like a dead grandma though.

That was you in front of me on the Interstate, huh? Get outta the way, man! Capable adults have places to go and shit to do. I loaded up the whole fam damily in the Lumina to go to my nephew's wedding last weekend. I pumped up the S-rated tires to 42 PSI cold (they are good for 44) to cut some rolling resistance. The trade off for a bit better mileage is a bit harsher ride and the need to work the brakes a bit harder to slow down.
Now, when I drive on the Interstate, I take pride in making up some time. If conditions warrant it, I will bend the speed limit as much as possible. It was 150 miles one way. Let's say the 30 MPG I could get dropped 10% due to my less than efficient driving style. My increased cost for gas to the event was $2 extra. BFD!
Drive like you mean it, not like old people.

Edit for spelling and content.

Posted: 6/7/2008 10:44:39 AM EDT

[#8]

Quoted:

Quoted:
It's the Ethanol.
Buy Premium gas, it doesn't have Ethanol, at least around here it doesn't.

If it's from Chevron, Conoco, Phillips, Union 76, Shell, Texaco or one of the other brands that complies with "Top Tier" specs, it does indeed contain 8 to 10 percent Ethanol.

Do that have to mark it at the pump? I buy from the Texaco across the street and it has no mention of ethanol but pretty much every pump I have been to thats in the boonies and away from large area, have 10% marked on a big sticker on the pump.

Posted: 6/7/2008 10:47:28 AM EDT

[#9]

Yes I've noticed my milage has gone down a good bit since right around the time I put in my 850cc injectors and 255l fuel pump. I wonder what it could be that's lowering my milage

Posted: 6/7/2008 10:50:27 AM EDT

[#10]

Back in 2007 my 2004 Toyota Corolla got about 36mpg. Then, starting sometime in 2008, it only got about 31-32, if I was lucky. It's a realtively new car, less than 35,000 miles on it right now, and it still runs absolutely perfectly.

Posted: 6/7/2008 10:55:37 AM EDT

[#11]

I think the warmer temperature is a big contributor. The engine runs much more efficiently with dense cooler air. I can tell a noticable difference in performance between winter and summer months.

Additionally, you're either running the AC or driving with the windows down, reducing mileage. Tires also become slightly stickier when it's hot out - improving handling, but also increasing friction with the road.

Posted: 6/7/2008 11:00:27 AM EDT

[#12]

Holding steady at 33 mpg in my 1998 Civic.

Posted: 6/7/2008 1:54:02 PM EDT

[#13]

Quoted:
To the people who record the number of miles between fill ups and calculate that way..

There are far too many variables for you to even come close to 10% accuracy. Just not going to happen!

If your statement was true, then I would see 10% variations from tank to tank, which I don't.

I cannot drive at exacting conditions from tank to tank, but the cumulative mean of the these tendencies is inherently normal.

Quoted:
If it's from Chevron, Conoco, Phillips, Union 76, Shell, Texaco or one of the other brands that complies with "Top Tier" specs, it does indeed contain 8 to 10 percent Ethanol.

Once again, Skibane hits the nail right on the head.

Fortunately, I don't buy fuel from those if I can avoid it. TOP TIER Gasoline Retailers I stick with Citgo, and BP Amoco as much as possible.

I saw this pic on BP's website. Doesn't it break your heart?

Posted: 6/7/2008 2:03:18 PM EDT

[#14]

I'm getting 50mpg in my harley (same as last year) and 20mpg in my SUV.. which I just verified today, I drove from my home in the metro denver area to Silverthorne on the other side of the Continental Divide and I still made 20mpg

thats the best I ever got in both of them

when they use that stupid "oxygenated" fuel here in the winter, mpg drops.

[ARCHIVED THREAD] - Any one else noticing decreased gas mileage on their vehicles lately (Page 2 of 2)

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