Influence of speed, temperature, and weight on MPG

This is very interesting data. However, from my understanding, the drag is proportional to rho times v^2.0 (rather than (rho * v)^2.0). Thus, shouldn't you divide the MPG by the drag rather than by the drag squared? Or I am missing something?

 

I think you may be underestimating electrical draw from the heater fan and rear defrost in your analysis. Also, the front defog setting runs the electric A/C to dry off the fog. The defog/floor setting does not use the A/C.

The rear defrost eats 1A at 300V in the NHW11. (300 watts) Add 20% for efficiency losses between the generator and battery and you have 1/2 horsepower.

Other electrical loads. 2003 NHW11.
Running lights: .12
Headlights: .57 A high beams .51 A low beams.
Brake lights: .37A
Rear defrost 1 A
Fan setting in amps: 1) .21 2) .34 3) .52 4) .65
Steering draws about 1A only while turning wheel, stopped, on gravel.

 

Wow - your average actual MPG, during the coldest months of the year and running at highway speeds of 70+, came out to 44.7mpg.

Two of your trips were above 48mpg actual - MORE than the EPA estimate for highway.

I can see now why you were so hysterical - not.

 

2008 EPA test procedure produced 50 MPG number based on 48 MPH average. Your average fuel economy was 44.7 MPG. Your average speed was 65.5 MPH.

The faster you go, the less MPG you get especially above 55 MPH.

 

It certainly was not at first...

Cherry-picking again... I didn't pay MSRP - sticker was $24500, I paid $23200 (before negotiating my trade-in). And this was before the recall fiasco. No doubt you paid less for your Sonata, but not much.

 

Thanks for this information! I hope someone with better statistical chops than I have might be able to tease out the effects of speed vs. the effect of temperature vs. weight and other factors from this.

Hope the Hyundai meets your needs better. With the amount of driving you do, I can see your lumbar support issue.

In six months, you can let us know if you think Hyundai and Korea are going to eat the lunch of the Japanese carmakers, the way the Japanese ate the lunch of American and European carmakers for the last few decades.