May Fuel Economy Stats

I'm a Prius newbie and one of the first things I learned from this group was to track mileage on fuelly.com. It's easy to see there how others' mileage varies with the seasons.

Love the fuelly site because I still own a first generation Honda CRV. More than one CRV owner has told me that they get 30 mpg. Per fuelly.com, BS. It verifies that most CRV owners get around what I do, 22 mpg plus or minus some.

My fuelly id is about the same as my priuschat id, GBC_Texas or something like that. If I got 22 driving a CRV when everyone else was getting 30, I figured I would be lucky to get in the 40's with a Prius.

Don't drive the CRV enough to put it on fuelly. Maybe the next time I fill it up, I'll add it to my garage.

 

So far for May

Date: 17 May 2010
Total Distance: 1211 miles
MFD = 61 mpg
Calculated = 58.5 mpg
Fuel added = 20.7 gallons

 

Date of 2nd fill: 17 May 2010
2-Tank Distance: 820.5
Fuel Added: 17.4 gal US
Mpg (calc)= 47.2 mpg
Mpg (disp) = 50.3 mpg (2nd tank only)

Remarks: I drive mostly interstates at about 70 mph ; 40 minute trips of 35 miles (obviously slower beginning and end); long time between trips, so essential new warm up each time I drive; still a bit disappointed I don't quite make the 48 mpg highway rating each tank.

 

You and I have similar length (time) drives. Two things will help your mileage and both are well within your control

1. Check your tire pressure and make sure you keep them well inflated. The closer you get to the max tire pressure, the more your mileage will improve.

2. Slow down. Back your speed down to 65 mph and you will likely milk another 1 - 3 mpg out of your drive. If you can even back it down closer to 60 mph, you'll see even more gains. It only SEEMS slower, it really isn't that much slower, less than 5 minutes from 70 mph to 60 mph (assuming that you can drive 70 mph for 30 miles of your 35 mile commute). Try 65 mph first and see how it works.

*edit* by the way 47.5 mpg = 48 mpg (with rounding)

 

This got me thinking. I exported my GasCubby app on my iPhone from when I got the car to the last fill, and exported the historical mean temperature nearby (weather underground), and graphed it. I was shocked to see such small variation, I thought there was a much bigger hit MPG wise. Although come to think of it, MPG and temperature on the same axis, so a big hit of 2-3 MPG is insignificant considering the large (20-30) swings in temp. Interesting none-the-less.

Only filled up once:
Date: 5/10/2010
Tank Distance: 461
Fuel Added: 9.461 gal US
Mpg (calc)= 48.7 mpg

 

Date: May 7 -14, 2010
Total Dist: 11,905 miles
Tank Dist: 386 miles
MFD: 54.5 mpg
Calc'd: 51.1 mpg
Fuel Added: 7.55 gallons

Remarks: 52 mile RT commute with 40 miles at 60 mph.

 

Thanks

 

Great tradition. Here is me:

Date: 10th April - 10th May 2010
Total Dist: 2644 km (1643 mi)
Tank Dist: 710 km (441 mi)
Calc'd: 5.42L/100km (43,4mpg)
Fuel Added: 38.5 litres (10.2 gal)

If you have an iPhone you might want to consider Fuel Log 3. You can enter your refills while at the pump, and then copy them here or upload to google docs and process the data on your PC or MAC.

I have taken over the development of Fuel Log. There are a few things planned for the next version. If you have comments or questions please feel free to ask.

 

Cannot report May data -- because with a late-April fill-up, it hasn't needed re-fuel during May, and may not need it until June.

Am on third tank.

Actual mileage on first two tanks (pre-May):
1st: 49.0
1nd: 48.0

And, this is without having really figured out how to apply my Gen II techniques to the Gen III, and simply using the cruise control when on highways (traffic permitting). And, tires still at factory pressures so I'll have a good baseline before changing things.

 

Good Thread and idea

Here is a screen shot of my spreadsheet that I keep. I have done this for the pass five vehicles, although for the Prius I did add U.S. mileage info along with the car computed info.



We picked up the car on April 14th and as of yesterday had 3,760 Km (2,336 mi) so yes very fun to drive.

Until my fill up yesterday my difference between computed verses calculated was running about 6%, but this last tank I got 12.2% which threw a bit of a curve into the numbers?

 

What startled me when looking at fuelly.com was how many Prius's were getting in the low to mid 40's. Perhaps coming out of winter explains some of it. But without so far doing much to stretch out my Gen III's mpg, and still with factory tire pressure, I've gotten 49.0 and 48.0 on my first two tanks

 

Date: 26 May 2010
Total Distance: 1813 miles
MFD = 62 mpg
Calculated = 58.9 mpg
Fuel added = 30.8 gallons

 

2 fillups in May
533.3 miles, 9.450 gals, 56.4 mpg
585.9 miles, 9.594 gals, 61.1 mpg (my first 60+mpg !)
total for may
1119.2 miles, 19.044 gals, 58.77 mpg

It's nice that the mpg's are going up now that winter is over.

 

Date: 29 May 2010
Total Distance: 1307 miles
MFD = 58.7 mpg
Calculated = 55.52 mpg
Fuel added = 23.53 gallons

 

1,575 miles

29.931 gallons

52.6 MPG calc'd
.

 

This is 2009 Prius so may not be a completely fair comparison but just for your reference:

(11164.3-10129.1)/(7.498+7.413) = 69.4 MPG (US) calculated for May 2010.

 

Date: 31 May 2010
Total Distance: 2332.1 miles
MFD = 62.1 mpg
Calculated = 59.1 mpg
Fuel added = 39.5 gallons

 

Date: 5/25/2011
Tank Dist: 431.3
MFD: 63.4 MPG US
Calc'd: 59.7 MPG US
Fuel Added: 7.215

Remarks: I was working on this tank and hoping to reach a goal of 60 mpg. I decided to lock it in when the MFD said 63.4 , but unexpectedly high MFD error prevented it. The dealer ran down the battery twice during service at the beginning of the tank so I was working against that the entire time. Also I didn't realize the dealer reset my tire pressures back to 35 psi.