What gas mileage do you get on freeway?

[cb3]

I average 34 mpg on freeway driving 68 mph on cruise control. This average is based on a 100 mile drive.

That is better than the 29 or 30 mpg it's rated for. Perhaps this is partly due to my KN air filter and using mid grade gas?

What gas mileage do you get on freeway?

 

[HotZ28]

A 100 mile drive is not a good test for gas mileage unless you filled the tank at the same location, same pump, same position of car & same full tank level. Drive for another 250 miles and fill it at the same location, same pump, same position of car & same tank level when filled.

 

[cb3]

It was my digital gas mileage monitor that is built into car's guages that said 34 mpg average.

I repeated the test several times and averaged 33 to 36 mpg each time. If I average all the tests together it averages approx 34 mpg.

 

[rodknock95]

Those are not all the way accurate. Fill it up as much as you can, usually when you know its getting close and back the flow down so the air can purge while filling it, the handle wont click out until its good and full. Anyhow, fill it up. Drive it until its almost empty, keeping track of how many miles you put on it, then fill it back up the same way, then divided the miles you drove by how much it took to fill it back up. Thats the only true way to know. As fuel injectors age and the components, they become less accurate.

 

[Cadillac_AL]

Mine will go over 400 miles on a tank of fuel. None of my other cars can do that.

 

[pila80]

Mine got 21, for all around driving. I did it but filling the tank twice, at the same pump & station. Not too impressive for gas mileage. My old '85 Caddy FWD Fleetwood beater does better, with 24 most of the time.

 

[Kevandkaye]

Typically, I'll net 21 per tank running around locally, mixed driving. Our annual trips to FLA and back always get 30-31 MPG down and back.... until we get to the "reformulated-winter" crap the Chicagoland area is forced to use. I just don't get how burning more fuel with less MPG's is making a difference?!?!?!? It loses about 3 miles a gallon all winter, so You are using more anyway!

 

[cb3]

Typically, I'll net 21 per tank running around locally, mixed driving. Our annual trips to FLA and back always get 30-31 MPG down and back.... until we get to the "reformulated-winter" crap the Chicagoland area is forced to use. I just don't get how burning more fuel with less MPG's is making a difference?!?!?!? It loses about 3 miles a gallon all winter, so You are using more anyway!

Is it losing gas mileage in Winter because of winter formulated gasoline, or because it runs colder in winter? Possibly a combination of the two?

All lubes are higher viscosity when cold (making things harder to move/turn), from engine oil to tranny oil to wheel bearing grease, all is colder, thicker, and stiffer and takes more power to make it turn when colder.

Also, gasoline burns less efficiently when engine is running colder. Mine runs around 194 F in Winter, and 205 F in Summer.

So I wonder how much of reduced Winter mileage is the gas, and how much is those other factors?

 

[Kevandkaye]

I believe it's fuel related. As soon as we get out of the "region" within 200 miles, the economy instantly recovers until we return every year. Two years ago, we followed record cold weather all the way down to Florida. Temps in the 30's the entire trip. Yet, mileage was over 30 MPG's until we got home. When an engine and trans are at operating temp, I highly doubt the outside influences make a difference unless it's extremely cold... It's easy to tell when they switch over here, even the Toyota can tell!

 

[cb3]

I believe it's fuel related. As soon as we get out of the "region" within 200 miles, the economy instantly recovers until we return every year. Two years ago, we followed record cold weather all the way down to Florida. Temps in the 30's the entire trip. Yet, mileage was over 30 MPG's until we got home. When an engine and trans are at operating temp, I highly doubt the outside influences make a difference unless it's extremely cold... It's easy to tell when they switch over here, even the Toyota can tell!

I think it's pretty well documented that machinery operates more efficiently in warm climates. Warm climates, not hot. However, quality of gas could make a difference too. What is less quality regarding Winter gas in your area?

The outside temp makes a big difference to my engine's "full" operating temp. The engines digital temp readout varies from 189 to 194 F on cold Winter days (depending on how fast I'm driving) on long drives. On Summer says, it varies from 196 to 207 F on long drives. So "full" operating temp is really a range, and it is affected by outside temperatures, whether or not it's raining, and how fast you drive.

 

[Kevandkaye]

Weird, this posted twice, but I'll leave one....

 

[Kevandkaye]

Is it losing gas mileage in Winter because of winter formulated gasoline, or because it runs colder in winter? Possibly a combination of the two?

All lubes are higher viscosity when cold (making things harder to move/turn), from engine oil to tranny oil to wheel bearing grease, all is colder, thicker, and stiffer and takes more power to make it turn when colder.

Also, gasoline burns less efficiently when engine is running colder. Mine runs around 194 F in Winter, and 205 F in Summer.

So I wonder how much of reduced Winter mileage is the gas, and how much is those other factors?

Believe whatever you want. But after owning and driving the same cars for the last ten years, and being in warmer than usual temps in October, March, and April, and seeing the difference before and after "winter" gas in all my vehicles, it's pretty obvious what is happening. I don't imagine these things, I actually calculate every tank of gas I use in all vehicles and have been for several years just out of habit ($$$$). Just talking from experience (I always practice hypermiling)... I know all about operating temps. Yes, they will suffer in extreme temps, hot or cold. but I'm talking full tanks, several fills,(fluids warm up) same driving, all year. The Tercel will get 36 MPG all summer, then suddenly, after winter gas, goes to 31-32 MPG's. You don't happen to work for a petroleum company, do you? BTW, I see you don't post where, or what year Buick you have......

 

[pila80]

I suppose the engine runs in open-loop longer in cold weather too, running rich for longer etc until the temp comes up, and it goes into closed loop.

 

[Kevandkaye]

It was my digital gas mileage monitor that is built into car's guages that said 34 mpg average.

I repeated the test several times and averaged 33 to 36 mpg each time. If I average all the tests together it averages approx 34 mpg.

In a stock Park Avenue, you aren't getting that kind of mileage without Tuning, fueling, hypermiling, and massive weight reduction. Period.

 

[timoch]

On my 1990 PA W/91k mi, I have been getting around 21 mpg all around driving, and 24 mpg freeway only.

 

[Maylar]

With the 99 Ultra I get the rated 27 on the freeway with cruise on. For my average driving which is mostly around town it goes down to 15. Some of that is not being able to keep my foot out of the Eaton.

 

[cb3]

Believe whatever you want. But after owning and driving the same cars for the last ten years, and being in warmer than usual temps in October, March, and April, and seeing the difference before and after "winter" gas in all my vehicles, it's pretty obvious what is happening. I don't imagine these things, I actually calculate every tank of gas I use in all vehicles and have been for several years just out of habit ($$$$). Just talking from experience (I always practice hypermiling)... I know all about operating temps. Yes, they will suffer in extreme temps, hot or cold. but I'm talking full tanks, several fills,(fluids warm up) same driving, all year. The Tercel will get 36 MPG all summer, then suddenly, after winter gas, goes to 31-32 MPG's. You don't happen to work for a petroleum company, do you? BTW, I see you don't post where, or what year Buick you have......

1997 Park Ave Base.

Yes, I am a weathy oil company executive who drives a 97 Park Ave and has nothing better to do than come to this forum in an attempt to fool you personally into liking Chicago area gasoline because your opinion is very very important to the oil industry.

Either that ^ is true, or you were out of line asking if I work for the oil industry. Which seems more likely?

Minor unpleasantness aside, thank you for sharing your experiences and opinions.

 

[Kevandkaye]

1997 Park Ave Base.

Yes, I am a weathy oil company executive who drives a 97 Park Ave and has nothing better to do than come to this forum in an attempt to fool you personally into liking Chicago area gasoline because your opinion is very very important to the oil industry.

Either that ^ is true, or you were out of line asking if I work for the oil industry. Which seems more likely?

Minor unpleasantness aside, thank you for sharing your experiences and opinions.

LOL! There wasn't any angst meant with that. That was merely a bad attempt at my dry humor...

 

[jrsroadhauze]

In my 93 PAU I get 17mpg around town and 27 to 30 on freeway.

 

[cb3]

I guess I'm lucky.

My Park Ave gets very good gas mileage. Seemingly impossibly good gas mileage.

It also has no mechanical problems of any kind. Seems to be the perfect car.

Note: A friend of mine has some other type full size GM car with same Buick 3.8 Series 2 engine and he says he gets 35 mpg highway. I don't remember the model of his car.

I don't know if my mpg meter is accurate, but a tank of gas lasts a long time.

My car does have a KN air filter, fresh tune up, and 195 thermostat. Perhaps those things help?