Thursday, August 24, 2017

MPG from Q50 on a Long Road Trip - Computer and Manual

Drove down from Madison, WI to Chesterfield, MO to watch the eclipse with the kids. Thought I would record the MPGs that the Q50 achieved during the mostly drive.

The summary is as follows per the car computer:
Total Miles Driven and Time Taken

Drove a total of 439.9 miles  before filling up and still had a range of of 49 miles.
Range - Miles remaining
So I could have done ~490 miles on a tank of gas, which is pretty impressive. The drive was 90% highway with a couple of stops, some in-town driving near St. Louis and one 8-10 mile traffic slowdown near Springfield.
Computer MPGs
The computer averaged 31.7 mpg, which is pretty good.

The important thing to remember is that when the car is stopped at a light and the engine is auto off, the computer timer is still running and the average mph keep dropping. The total time was 7 hrs and 12 mins of engine on time, not necessarily driving.

Computer Average Speed
The average speed was recorded as 61 mpg. The highway speeds that I drove were 75-80 mph with a few higher bursts :-), otherwise in city. This is important because my noral in down driving has a lower mpgs, but the average is usually 30-40mph.

Tire pressures
Since the tire pressures and temperature affects The cold was 35 PSI at 70 F and it was a 85-90 F day, the hot temp was 38 PSI.
Total and Trip eV Miles
The total eV miles were 37.6 miles which is pretty good for 439.9 miles total.

The actual gas mileage is measured by fill-up to fill-up, since the tank was filled up before leaving using 93 octne from Mobil gas station near home. The tank took 14.678 gallons, so that is what was how much gas I used.
Gas Filled Up after Drive

Doing the manual math gives:

439.9 mile/14.678 gallons = 29.97 mpg, so about 1.72 mpg off from the computer.

Subtracting the eV miles gives 439.9-37.6 = 402.3 miles / 14.678 gallons = 27.40 mpg.

So the hybrid added 29.97 - 27. 40 = 2.57 mpg more.

For those that have the hybrid, you have probably noticed that there are times that the engine runs during coasting instead of shutting off and all it does it charge the battery instead of going into eV mode completely. So basically some of those mpgs arre offset by that usage as well.

Overall I am not surprised that the computer is off as there are many factors it assumes based on fuel flow and time, but I am pretty happy that eV gets me an extra 2.57 mpg for 90% highway.