Onewolf42

I have never been able to figure out how my 2018 A4 Quattro calculates the fuel "range". Immediately after I fill the tank the range displays somewhere between 510-530 miles. The fuel warning light comes on after about 320 miles and the fuel range indicates I have 60-65 miles range. The farthest I have gone on a single tank is 360 miles and the fuel range said 15 miles at that point.

Neither the actual short term nor long term fuel economy displayed calculates close to 500+ mile range. The only way to get a 525 mile range is if you assume the full 15.3 gallon tank capacity and 35+ MPG (Which my car would only get if coasting downhill).

So.... how does Audi calculate the fuel range?

Thanks.

bob m

More and better techy responses will be coming, but the short answer to how does Audi calculate mileage - is overly optimistic.

Onewolf42

There must be an equation in there somewhere. It's so far off maybe they missed a metric conversion.

KevinGary

Daaavid

It has been fairly accurate for me. I use Fuelly to track my fuel mileage and costs. I reset my trip computer in the vehicle after every fuel up as well.

The funny thing is that the range estimate in the vehicle always goes in increments of 0s and 5s, so you'll never see "213 miles." It will round to 215 miles.

However, if you go into your myAudi app, it will show the exact fuel range and percentage in your gas tank.

And the fuel range estimate goes off based on your most current driving conditions. I don't know the equation on this, and I doubt anyone does, but it's usually based on what your driving characteristics were right before your fuel up.

I would never attempt to run the car near empty as you run the risk of overheating the fuel pump; it uses the fuel in the tank to cool itself. Also, there is a huge buffer in what it classifies as "low fuel" for (a) making sure you are aware, (2) you should get gas, and (3) to not damage itself. So even if the range went down to 0 and you are critically at empty, you still have about 1-2 gallons left.

traumeri

The MPG via Audi's computer also overestimate by 3-4% every time I compare to hand calculated MPG when I fill up. Where the error occurs who knows, but it does reduce my trust in the "remaining range" number and I try to fill up before it goes below 20 miles.

BeefJerky

Interesting, my MPG always tends to underestimate by about .5 MPG. For example, it may say my long term (since last tank fill for me) is 31.5, but then when I calculate it myself after filling, it will be more like 32. That said, my previous cars ('16 Camry and '08 CR-V) both overestimated by a larger margin; usually around 1-2 MPG.

As for the range estimate, mine always starts way high as well. It tends to become more accurate after driving for awhile.

caranddriver

The range is definitely conservative, it tries to scare you into getting gas. Even when near zero, there is like 1.5 gallons of gas left.

superswiss

The remaining range estimate is supposed to be based on your average consumption for the last 18 miles if I remember correctly. So, [avg mpg over last 18 miles] * 15.3.

PghRich

I also see 500+ after a refill, and my drive around town and to the gas station certainly isn't getting me 33+mpg.

It seems like it takes my average highway mileage, which is 33-34, and uses that. It then rapidly adjusts after the first 10-20 miles down to something that could be based on actual driving.

The fuel warning light coming on at 60-65 miles is normal, in my experience. My M5 was 68 miles, iirc, my wife's 328 is about 70 miles. Only my daughter's old RX-350 waits until 18 miles, which is way late, IMHO.