Those of you that calculate your fuel economy and compare it to the display value, how do the numbers compare for the Highlander Hybrid?

For my 2006 Honda Civic Hybrid, through over 16,000 miles, the display fuel economy averages 1.3 % low. I believe most people say the Prius display reads high. I was hoping that the Highlander Hybrid would also read low as I prefer to be pleasantly surprised when filling up at the pump, but I would imagine that it is more in line with the Prius.

I'm still on my first tank.

Thanks.

 

I have a spreadsheet with all my MPG and maintenance info, and on average the actual values are running about 5.2% below the computed values. In individual tanks, I've had differences as high as 10% between the two, and as low as 0.7%. We're not talking a ton of tanks here, so I wouldn't treat this as normal expectations for your situation.

More imporantly, compared to if I had continued driving my old SUV, I'm averaging a savings of about 9.5 gallons per tank (assuming exact same driving needs and that the SUV could hold enough gas to make the same mileage trip as the HyHi).

 

I have a database of all 22 fill-ups for my HiHy. The MPG display is optimistic by 4.00% over all those tanks cumulatively based on actual gallons used vs MPG-display-calculated gallons for each fill-up.

This equates to actual MPG about 1.1 MPG lower than the display.

In warmer weather the mpg display was high by about 3.5%. In very cold winter temps, it was high by about 5%

For some good news, you may want to check your odometer's calibration. On My HiHy, the odometer runs fast by 1.5%. this was checked by using my GPS mileage display and corroborated with highway mileage markers. When the trip mileage display indicates 100 miles, I actually have traveled 98.5 miles. This improves your MPG by 1.5% over both the MPG meter and manual calculation using miles and gallons.

Note that I have the Michelin tires. If you have the Goodyear tires, this error will be less, as the Goodyear tires have a marginally smaller rolling circumference than the Michelin.

 

[quote=Don R;127691]
For some good news, you may want to check your odometer's calibration. On My HiHy, the odometer runs fast by 1.5%. When the trip mileage display indicates 100 miles, I actually have traveled 98.5 miles. This improves your MPG by 1.5% over both the MPG meter and manual calculation using miles and gallons. quote]


ERROR: I got this backward. The odometer runs SLOW. When the the trip odometer reads 98.5 miles, I have actually traveled 100 miles. This improves MPG by about 1.5 % and lengthens your mileage warranty.

 

Well, I just filled up and my dash errors are right in line with your experiences. The dash displayed 37.3 mpg after 503 miles, but I only put in 14.881 gallons for 35.82 mpg and a difference of 4.14%. We'll see how this trend continues.

 

I've observed similar on vehicle (appears to clock 1 mile for an actual 1.1 mile. I'll have to double-check, but I recall coming to the same "lengthen my warranty" thought).

I was hesitant to mention that the odometer would modify the MPG rating for one small reason: whether you calculate by hand or use the computer's calculation, it doesn't matter whether the odometer is off or not if you're using that same odometer/trip mileage value in both equations.

 

My 07 HH runs about right on actually. I was driving across the country and I was filling the tank to the spill point on each stop so I could accurately measure the mileage vs. the MPG the computer calculated. I did not know about the over filling risk at the time, so I would not do it again, but either way, I was burning the fuel out in a matter of minutes makeing space in the tank.

My observation with 3 folks and lots of gear in the car that your fuel economy plummets above 65 and at 80+ it is doing so so. Around 25 mpg.

 

I did quite a bit of interstate driving today on I-70. At some point, I decided to try and check and see how accurate the odometer is. I went from mile marker 163 to 77, a distance of 86 miles. The trip odometer only showed 83.8 miles. This means that my odometer mileage needs to be increased by 2.63% to be accurate. I'll check again on my drive home if we stay on the interstate much.

When I filled up earlier today, my calculated fuel economy (gallons put in divided by odometer miles driven) was only 1% lower than the display. We'll see how this trend continues. I don't typically top off, so I can get a bit of tank to tank variance. Anyway, I may start adjusting my miles driven using the calibration factor I measured today.

I have the Goodyear tires and they were at 43 psi cold this morning.

In my Civic, the navi has a diagnostics screen that can show a lot of information. Among the many things it shows are the speed calculated from GPS and also tire calibration. The GPS reads identical to the cars digital speedometer. The tire calibration is set to automatic. I guess this means that it periodically uses the GPS calculated speed to calibrate the tire size.

 

My computer is always 1-5% optomistic. So it's about 1 MPG high.

 

I am going to use a handheld GPS to calibrate my odometer. Then I'll really see how accurate everything is.