MPG in the mountains?

I generally go up to my mountain place once a month and have the experience of comparing several cars of very different size and power in their mpg. No matter which one they all suffer significant mpg losses. Generally I can say the weight of the loaded car compared to unloaded weight is the biggest difference. The Prius suffers the most loss as would be expected on a light, low torque engined car compared to a heavy, large torque engined car. BUT even with the smaller loss, the heavy cars had far less mpg than the Prius C. And the loss in speed is significant even when the roads get very twisty. So pick - faster getting there vs far better mpg. still, my Prius C is preferred when gas costs $3.69 a gallon at 40 mpg insread of 16. OK, sometimes.</p

 

I took my C some of the way up Mt. Cardigan in Vermont two weeks ago (there's a fairly steep drive to where the trails begin). You could really tell the engine was working hard, and displayed MPG dropped to 43-ish on the way up, but I got 70+ on the way down, so I still averaged out OK for the whole trip.

 

I didn't have any cargo though, and there were four adults in the car including myself

 

I drive a canyon about every other week or so. It's a 65 mile treck each way with about a 1800' gain in height.

My PC is almost two months old now. The canyon does have a hit on MPG BUT it works both ways up & down.
On my run I get around 50 MPG going up hill. On the down hill run I get over 60 MPG.
I do drive sensibly as I drive this run a lot and always plan on having time to spare. Average speeds are between 50-65 based on the stretch I am driving. Tire pressure 42/40. I use the bar graph to monitor MPG as I drive. It's just me in the car so your load will take a hit on MPG.

It takes me a few minutes longer than the Zoom Zoom drivers but it puts a BIG smile on my face when I pull up to the gas pump.

My previous car was a Saturn VUE that I used to gloat to others about my gas mileage on that trip (28 MPG average). The PC has cut my gas consumption in half over the VUE. Others that visit me (With bigger fancier cars) are always complaining about how much it cost them to visit me so they ask me to visit them. Some of then even offer to pay for my gas as it would save then so much money if I did the driving.


John

 

The non-linear American MPG scale is a rotten way to figure fuel economy differences in this situation. A different measure, Gallons per 100 miles (analogous to the liters per 100 km scale used by most of the planet) should be more useful. On this scale, I'd expect that the extra fuel needed by the Prius C would be no larger than the extra fuel needed by any traditionally powered car.

My Prius liftback typically burns one extra gallon per 10,000 feet of climb (+/- 15%), in addition to the fuel it would burn for a flat road of the same distance. If the slope is shallow, say a 1-3% grade, then nearly all of that fuel 'investment' (or penalty) can be recovered on the descent by judicious use of gliding with minimal use of friction or 'B' mode braking. But long steeper descents require most of that fuel 'investment' spent on the climb to be thrown away as braking heat.

A Prius 'c' should be very similar. For the heavier load, add roughly 20% to the extra climbing fuel, e.g plan for 1 gallon per 8,000 feet of climb. I don't think you will find regular cars doing any better, but their lower MPG figures are much better at hiding this factor.

 

Woooooooo!! Was going through a bunch of steep roads in the White Mountains and I had the battery full to all 8 bars, finally... I ran the engine brake the whole way down some of these hills. Going up I had the rpms up to 3000 and barely made it up. Average up-trip fuel economy was 50 mpg, average down-trip fuel economy was 85 mpg until I hit a traffic jam.
So basically, long uphills will probably bring your fuel economy down to the 30s or 40s until the hills flatten out. Going down, hit the engine brake. Man, these roads are steep!!