Best Actual MPG! - Smart Car of America Forums : Smart Car Forum

DoraAnderson · 09-23-2009, 08:09 AM

Filled up today from a tank used exclusively on the Houston freeways going 75-80 mph (or more) and got my best actual mileage... 40.3 mpg, as opposed to my normal 35.5 when I "hypermile." Happy me, but I don't like freeways!

chumly · 09-23-2009, 08:29 AM

t he best I've gotten is 54 mpg by driving 50 mph (when traffic permits) and using cruise control sparingly.Yesterday I was able to get over 50 mpg city driving according to my scanguage (the lights were with me for a long time).Drive slower and you would be suprised how much mileage improves and I was passed several times but caught up with them by the time I got where I was going.I also kept it in 5th gear as long as possible without lugging and using a very light foot.I couldn't tell you how many times I have been passed by some gas hog going 80 mph only to catch up within a few miles because of traffic.

**rfernatt** · 09-23-2009, 08:53 AM

You really need to average the miles across several tanks to account for pump fill differences to get a relatively accurate number. Even a small amount of fuel will make a big difference in the MPG on the smart with such a small tank.

For example, two tanks ago my MPG for the tank was 49.7. This past tank it was 42.3. Nothing changed in my driving between the tanks. If you average those two tanks together you get 46 MPG and that is about what I've averaged on the past 10 fill-ups. Although 49.7 looks good, it was probably an early pump shutoff that caught up with me on the next tank. It all averages out in the end!

Oh, and try Fuelly.com to track your fuel mileage!

chumly · 09-23-2009, 09:27 AM

I understand about averaging several tanks,I have been filling up at the same pump for a long time so I know I am getting the accurate amount every time. I fill up until I see the gas (top off).I know your not supposed to but I burn the gas immediatly and never had a problem yet in the last 30-40 years.

Kermit · 09-23-2009, 10:01 AM

Quote:

Originally Posted by DoraAnderson

Filled up today from a tank used exclusively on the Houston freeways going 75-80 mph (or more) and got my best actual mileage... 40.3 mpg, as opposed to my normal 35.5 when I "hypermile." Happy me, but I don't like freeways!

Congrats - come back here and tell us what your next tank is to. Just like they mentioned before, you get a real good picture of your mileage over several tanks but it is so good to see a nice tank every so often.

**rfernatt** · 09-23-2009, 10:13 AM

Quote:

Originally Posted by chumly

I understand about averaging several tanks,I have been filling up at the same pump for a long time so I know I am getting the accurate amount every time. I fill up until I see the gas (top off).I know your not supposed to but I burn the gas immediatly and never had a problem yet in the last 30-40 years.

The 49.7 and 42.3 tanks were pumped from the same pump at the same station on the slowest setting and I stop at the first click every time. I still think there are too many variables in the fill process to trust even a single pump to be accurate every time: normal pump margin of error % in fill, normal shutoff variation, ambient temperature, temperature of fuel (did the tanker just fill up the station tanks after a four hour haul in the sun?), was the pump checked/adjusted since your last fill-up, how full was your tank when you started, etc.

unicycle · 09-23-2009, 12:35 PM

As usual, an MPG thread started with too little knowledge behind it. I should know -- I started one last year about getting 54 mpg on a tank, only to realize later that the pump had shut off too early and that I'd traveled too little to get an accurate reading. I especially love the idea of driving faster and less economically than usual and somehow getting better milage, as if the car's sweet spot is in the 65-70 mph range. 'Taint.

As others have noted: Yeah, it's all about averaging at least two (and pref'ly several) tanks.

Having said that, I can fairly accurately report that I'm now getting 49.8 mpg over the past nine tankfuls. I have a ScanGauge, I rarely rev over 3000 rpm, I drive c. 90% highway (tho I have some decent elevation), and I average 55 mph or so. My only hypermile trick other than driving slowly is to use the pulse & glide technique.

DoraAnderson · 09-23-2009, 02:29 PM

All those suggestions already taken into consideration, but I was still happy/stunned that the super high-speed tank of gas was my best yet! I had expected the opposite. I still have many trips to the medical center coming up the next few days, on Houston freeways as opposed to my normal country roads, so we'll see!

NCC1701 · 09-23-2009, 04:16 PM

Quote:

Originally Posted by unicycle

I especially love the idea of driving faster and less economically than usual and somehow getting better milage, as if the car's sweet spot is in the 65-70 mph range. 'Taint.

You're the expert. However, with close to 60 tanks on my smart, my best tank was haulin' butt on the Interstate, and it beat my overall average by 24%. 43.5 MPG.

DoraAnderson · 09-23-2009, 04:41 PM

Quote:

Originally Posted by NCC1701

You're the expert. However, with close to 60 tanks on my smart, my best tank was haulin' butt on the Interstate, and it beat my overall average by 24%. 43.5 MPG.

Thanks!
Here's mine: