localh85

There is not much in the manual about how this is calculated, but I am wondering if anyone has some extra insight on the fuel gauge and its mileage estimate it outputs once we fill up the tanks.

Having gone on a small trip recently, I tried a number of different gas stations along the way. Below is roughly what the gauge was estimating for me once it was full.


Chevron: ~420 miles (sampled once)
BP: ~ 390 miles (sampled twice, roughly the same))
Exxon: ~ 370 miles (sampled twice, roughly the same)
Shell: ~ 370 miles (sampled twice, roughly the same)
Sams Club: ~ 350 miles (sampled four times, roughly the same)
Costco: ~ 300 miles (sampled once)


Clearly there is something about the gas which creates these different initial estimates and I am wondering if this initial calculation (does anyone know what exactly it is doing?) is in anyway useful to determining the best value for gas by price.

jsykes

It has nothing to do with the fuel type, the way its figured out is using the current rate of use and how many gallons are remaining in the tank.

So if you got right off the highway and were averaging 30mpg when you fueled at Chevron, when you start back up the range will be greater cause its assuming you're going to continue getting 30mpg.

If you pulled off the highway and had been averaging 28mpg and then drove on surface roads for a bit where you were only averaging 20mpg, when you get back in the car after filling the car will show a shorter range since its assuming you're only getting 20mpg at that point.

If you were to get back on the highway and start averaging higher mpg, the range will slowly increase as it continues to figure out the remaining range based on your current rate of consumption.

It has no way of knowing what kind of fuel you're putting in the car at fill up.

localh85

Interesting, that makes a lot of sense, thanks!

extanker

my goodnesss....better check with the dealer on this dilemma

Philip Goughary

To add to above, the fuel that you're putting in your car is all the same regardless of brand. Don't let marketing gimmicks like "V-Power" or "Techron" or any of that kind of language fool you. The vast majority of the gasoline you buy is commingled at the truck racks, and/or in the pipelines its shipped on. That "special additive" each major pretends is in their fuel is nothing more than a cup of snake out poured in at the last minute so that they can keep from being accused of false advertising.

I'm an oil products broker for credibility reference, specializing in finished gasoline and distillates.

dgrobs

So my wife and I ran 3 days at Pocono with RTR last weekend.
We'd fill the 981S up at lunchtime, and once full, it only showed 78 to 80 miles of range in the FULL TANK.
Def related to your driving speed and conditions right before you fill up.
When we left Pocono Sunday afternoon, filled up at a local station right before getting on 80 East, and the range showed about 90 miles in the full tank.
By the time we hit the Jersey State Line, the same tank of gas was showing a 360 mile range. (Best mileage we've ever gotten..lol)
The on board computer assumes you will continue to drive the same after the fill up as you were before the fill up.
Great question and great answer above. Spot on.