Rovman

I decided to drive my GT3 for this weeks business trip to Houston. I can't say this enough but I absolutely love this car and can't stop driving it. One would not think that this car would make a good company/work car but it swallowed up all of my weeks bags with room to spare.

One of the observations I made today during my 3.5 hour drive was specific to the fuel level reading. My car has the zero cost larger fuel tank option.
I filled up this morning and noticed I drove on the Interstate about 130 miles before the fuel gauge finally started coming off of "full - 4/4".

I thought I had noticed this before but didn't really notice the mileage before movement so today I payed attention.

I wonder if there is only one fuel level calibration for both tank sizes.
Doing simple math, this would equate to roughly burning 6 gallons of fuel before the fuel level starts to move. (Using 20.5/21 mpg while at speed on the interstate)

Not that it's a big deal, just would expect the fuel gauge to be a little more accurate than that. Thought maybe I would mention it and see if someone else has observed the same with their car.

It would be interesting to hear if this happens with the smaller fuel tank optioned cars.

In the past I have seen a few of my cars fuel gauges calibration not have a linear depletion curve. No where near as this extreme. Just didn't expect this from Porsche.

Even so, Love this car. Thought I would share some meaningless observations.

NateOZ

Have the large fuel tank as well and gauge doesn't move until I get through the extra fuel.

Jimmy-D

Same here. It is accurate but only when the needle at "F" starts working(kicks in)

PC Valkyrie

I have noticed the same thing. Glad it's normal.

RFGGT3

Ditto

bigkraig

+1, I was hoping it would calibrate itself. Guess not.

ipse dixit

Lots of fuel tanks (not just Porsches, or 991 GT3s) exhibit this syndrome.

I think, from what I am told, it's just the way the fuel tank is shaped and the location of the sensor.

Mike in CA

My fuel gauge responds the same way; it takes a while to start moving at the full end. But honestly, with both the multi function display and PCM providing accurate range info so that you don't have to guess about how far you can go on remaining fuel, the gauge has become kind of an anachronism anyway.

bronson7

I agree, most fuel tanks are similar.

ADias

If this behavior only happens with the larger tank, it may be a gauge software calibration issue and PAG might be able to fix it with a software update. I would inquire about it.

A simple IF statement line of code based on fuel tank size.

Lodi

The car has a fuel gauge?

ipse dixit

Yeah, it's the dial that goes in the opposite direction of the tach. And almost as fast.

Zulu Alpha

Mine is the same. I have a relative who has a Land Cruiser L200 Series, he installed a 180 liter fuel tank and says the needle didn't move till 400 KM into the drive! Haha. guess it's the same functionality.

Sloopy

Ok, now that you mention it, that is the case however I did not notice until you brought it up.

Just to enamored with the rest of the car...

<3mph

I don't recall exactly all the details anymore, but while on the factory tour last spring, our guide took a few moments to show us the 991 fuel tanks. The shape is really very complex and beautiful, and takes advantage of a lot of unused nooks and crannies in adjacent spaces. It is quite the work of art! As a result, it is my understanding that the fuel level sensor in modern Porsches therefore does not take a linear mechanical measurement. The float sends information which is then translated electronically into a computed fuel level to account for the shape of the tank. I would think that it should be quite simple to adjust the programming for the 90L extended fuel tank then. Hopefully this can be rectified. I'm sure someone on here with more knowledge than me will be able to elaborate and/or correct me.

I'm totally with you on how annoying it is when the fuel gauge is not providing meaningful readings.