2023 Prius LTD Mileage for a 700 trip

Last week, I took a mid-week excursion from the SF Bay Area through the northern Sierra to the base of Mt. Shasta (town of McCloud) and did a straight- one-day return to the Bay Area on the Interstate. I filled the tank at the beginning of the trip, in McCloud as I began the return, and at the finish.

So, at the end of the outbound leg, I had traveled 426 miles with the tank mileage shown as 50.0 mpg. The primary elevation contour of the trip was from sea level to 2500 feet, then to 3300 feet, passing a summit at 6500 feet. Then I went up to 5800 feet and returned to 3300 feet. Speeds in the mountains never exceeded 65 mph, with most travel between 40 and 55 mph.

Leaving McCloud, there was a 5-mile, 1,000-foot climb, but the remainder of the trip home was first downhill and then flat for 270 miles. The mileage for this segment was 45.9 mpg. Much of it was driven at speeds near and above 70mph, with the A/C cooling the car down from an outside temperature of 105°F to 75°F. In particular, one 60-mile segment of flat terrain showed a reading of under 38 mpg.

The fuel tank capacity is rated at 11.3 gallons. When I refueled in McCloud, the fuel odometer was about 60 miles to empty, and the car took 8.5 gallons. So, the tank fuel gauge appears to be accurate. However, 60 miles to empty suggests a practical tank capacity of about 9.5 to 10 gallons. Whether this is a miscalibration of gauge, an early cutoff for fueling, or just Toyota providing a safety margin on the 'miles to go' reading will take a few more refuelings to figure out.

Note: my standard practice for years in fueling a car is to keep fueling until the pump clicks off, pull the hose back to break the seal, push it back to reseal it, and start again. If it clicks off within a few seconds, I stop. Otherwise, I keep going and repeat the procedure. In McCloud, I cycled once, and a tiny amount of fuel was visible and clearing the filler when I removed the hose. The filler was empty when I secured the cap.

 

It's an FWD Prius Limited (not Prime).