Significant Jump in MPG After Freeway Drive

[BRZnut]

Originally Posted by carma143

Well there are lots of hills where I live. My home sits at around 400 ft above the ocean, while one of the middle schools in my city sits at around 1260 ft above the ocean. My old preschool sits at 115 ft above the ocean. Driving up a hill in 5th gear nets better mpg than in 6th because, since the small amount of torque in 6th, requires to press more on the gas pedal.

Edit: I will say that it is VERY cool to drive on roads entering the fog layer, and then after 1 minute of not being able to see more than 20 feet on front of you, exit the top of the layer to tranquil sunshine and a beautiful view of the surrounding ocean. :P

The endless switchbacks required to go nearly anywhere in town probably have to do something with the mpg as well.

Up and down hills can do it but at least you have some interesting roads to drive on, unlike much of the east coast!

[DeeezNuuuts83]

Have you compared it to your actual mpg based on your miles driven and fuel put in? The car itself might give you an idea of when your mpg is better or worse, but the numbers themselves are generally far off of what you're actually getting.

[carma143]

Originally Posted by DeeezNuuuts83

Have you compared it to your actual mpg based on your miles driven and fuel put in? The car itself might give you an idea of when your mpg is better or worse, but the numbers themselves are generally far off of what you're actually getting.

Will using the "low fuel" light be sufficient in calculating the beginning and end of the calculation?

[DeeezNuuuts83]

Not really.

Just make a habit of filling up your tank completely. Top off your fuel tank, reset trip meter, drive, top off your fuel tank again whenever you want/need to, then divide the trip meter mileage by the gallons that you put in, and you have your tank average (or at least as close as you can get to it). Repeat.

If you compare those numbers to whatever your car says, even if you reset it at each tank, the car will report more optimistic numbers. I think part of it is because when the car is idle and at a stop, I believe that it does not include that fuel consumption in its calculations (which is why it's usually blank, or something like "--.- mpg," instead of reading 0), even though fuel is being burned while not moving.

[gravitylover]

Originally Posted by DeeezNuuuts83

Not really.
I think part of it is because when the car is idle and at a stop, I believe that it does not include that fuel consumption in its calculations (which is why it's usually blank, or something like "--.- mpg," instead of reading 0), even though fuel is being burned while not moving.

That's the first time I've heard that theory and it makes good sense. My regular couple hundred miles between fill ups generally includes a fair bit of traffic time and I usually get 1-2 mpg less than indicated but when it's a straight highway run with little to no sitting in traffic it's just about spot on.

In my last car (XV Crosstrek) I would reset trip A every fill up to get close to current avg mpg and leave trip B for oil change intervals and that avg was always WAY less than for individual tanks. With this car it doesn't work the same, you need to reset the avg mpg every time, it doesn't read separately for the two.

[strat61caster]

Originally Posted by DeeezNuuuts83

If you compare those numbers to whatever your car says, even if you reset it at each tank, the car will report more optimistic numbers. I think part of it is because when the car is idle and at a stop, I believe that it does not include that fuel consumption in its calculations (which is why it's usually blank, or something like "--.- mpg," instead of reading 0), even though fuel is being burned while not moving.

Yes it does, reset it, do some constant speed for a mile or two, get that number up to >20 mpg and then sit still and idle, watch the number drop.

Pretty sure every manufacturer is doing what they can to inflate the egos of owners, every car I've had experience with from Acura to Ford is optimistic at least 5%-10%.

[carma143]

Update: after driving nearly 10/10ths with the majority of my current tank around where I live, and after a drive up and down the switchbacks (an hour detour from school to home), I checked the mpg reading, which now shows ~22.8 mpg after a reset of the mpg reader, which was performed soon after my previous post on this discussion. This is at ~1/4 tank.

When driving normally around, I used to eek out 20 mpg and ~19.1 mpg if I drove the entire fuel tank 10/10ths.

I'll respond again when I have refueled and expended the next tank.

[swarb]

don't use the mpg meter. It's not accurate. Use fuelly ap or a calculator. My mpg meter is off/over 1.5-2mpg. Here is my fuelly http://www.fuelly.com/driver/swarbrz

[carma143]

UPDATE:

I arrived today at Costco to refuel with 91 octane gas. 204.9mi / 9.591 gal = ~21.36 mpg.

Avg. fuel economy was found by sensors to be 22.4 mpg.

[evan]

Originally Posted by carma143

Well there are lots of hills where I live. My home sits at around 400 ft above the ocean, while one of the middle schools in my city sits at around 1260 ft above the ocean. My old preschool sits at 115 ft above the ocean. Driving up a hill in 5th gear nets better mpg than in 6th because, since the small amount of torque in 6th, requires to press more on the gas pedal.

Edit: I will say that it is VERY cool to drive on roads entering the fog layer, and then after 1 minute of not being able to see more than 20 feet on front of you, exit the top of the layer to tranquil sunshine and a beautiful view of the surrounding ocean. :P

The endless switchbacks required to go nearly anywhere in town probably have to do something with the mpg as well.

Why stop with the elevation of your middle school and your old preschool? I'd like to know the elevation of your local Albertson's and Joe's Crab Shack. I've found better MPG in the grocery parking lot versus say the high school around the corner. In fact, after boost and fuel, I find myself singing the "I want my MPG" song ( [ame]https://m.youtube.com/watch?v=PaGrxPh-2RI[/ame] )..by myself..in the dark..when nobody is looking.

[carma143]

Originally Posted by evan

Why stop with the elevation of your middle school and your old preschool? I'd like to know the elevation of your local Albertson's and Joe's Crab Shack. I've found better MPG in the grocery parking lot versus say the high school around the corner. In fact, after boost and fuel, I find myself singing the "I want my MPG" song (

)..by myself..in the dark..when nobody is looking.

Understandable for Gollum...

[iSnack0nEmoKidz]

Miles/Gallons=MPG

The sensor in the car is off by at least a solid 1 MPG. Our sweet spot is a little below 3K RPM. That will give you really good MPG because driving mostly highway, Ive achieved an average of 37 mpg.... But thats coz i travel like 70 miles to work everyday.

21 mpg avg is puuuuurty poopy.... Evren with mostly city driving... I have a manual and spending a whole day downtown austin, i still managed about 28mpg...