Fuel question

71.5mpg sounds way too high; 40mpg seems a bit low. It all depends on speed, up/down hills? driving technique, running AC, main battery SOC, etc? I wouldn't gauge my mpg based on just 12 miles.

 

Check the 12v battery on both vehicles. Wait till thr cars have been sitting overnight then use a digital volt meter to check voltage at the battery. You want to see at least 12.4 v.

 

That could be a factor, throwing off your calculation. Wait till you've had at least 2 tank refills on each car, fill careully, by the same method.

12.4 Volt sounds a bit low. I'd peg the low end for a healthy battery at 12.6 Volt. That's reading when you haven't just tried charging, which would push the reading artificially high.

 

What are the tire pressures? This can have a big effect on mileage.

 

keep the white and sell the grey.

 

Check the oil first, then the tire pressures. (Oil first because that can do serious damage if incorrect, as well as affecting MPGs.)

12 miles is nothing. 12 tankfuls might be meaningful.

 

I agree but it is high enough to not be considered bad or seriously affect fuel economy. Mine is a 12.4v and with my 15" wheels I can stil achieve 52mpg without trying and over 55mpg with a bit of effort. I have a 95% highway commute at 65mph-70mph and a 1200 ft. elevation gain to boot.

 

Mines also only 12.4 volts measured at the battery terminals and 12.3 volts (in accessory mode with no other loading) at the MFD signal check. I'm getting solid 55 MPG and am happy enough with that figure.

As for measuring the FE over just 12 miles I echo Richards comment. Post back after 12 tanks when the results are meaningful and there are lots of little things that we can look into that can impact the fuel mileage.

BTW. After reading this thread this morning I was tempted to post my own cheeky thread titled "Help me I'm only getting 2.3 MPG". The reason? Well I filled up today and just as exiting the fill station driveway I glanced at the MFD and noticed it read "0km 99.9 L/100km (which is 2.3MPG).

 

Or the inverse:

We've sometimes tanked up at this station just at the start of a wonderful long downhill drop. It's a real ego stoker to get to the bottom, and then glide another km or so, and have insanely good mileage.