I have never seen 30mpg on my 991.1s typically average 13-15mpg. 18-21 if I try, thought maybe fresh plugs and filters would help but they can't fix your foot.
Really want to tell myself better mileage is why I need a .2 but I love the sound and paid for part of mine.
Until I got my wife a diesel X5, my 996 turbo got the best, easily 20mpg even having fun.
They should have extended range tank options on all versions, convenient to go to gas stations less often.

 

I can manage around 7.5 l / 100 km on the highway at 125 km/h

My normal driving is around 13-14 l / 100 km

 

Just did a waste-of-gas test of my 991.1 C4S with 94 miles of pure freeway driving keeping it at 70 mph as closely as possible in normal (non-sport) mode. Filled up at a station near the freeway, and filled up at the exact same pump after about 1.4 hours of freeway driving. Ambient temperature was 75F.

Results:
MPG: 29.8
Mean Oil Temp: 225 F

My dashboard fuel consumption meter registered 30.9 mpg at the end of the trip, so it was about 1.1 mpg too generous compared to the actual calculation. One thing I noticed was that the dash gauge reading (and the actual mileage) is very sensitive to any change in elevation. A slight uphill will kill the mileage and a slight downhill will really boost it. Any test should ideally be on extremely flat roads with the beginning and ending points at the same elevation. Hilly terrains will cause the milage to suffer even with starting and ending at the same point (downhill gas savings do not completely make up for gas loss on climbs).

 

Over 18K miles and my average has been between 17-18 mpg.

 

What's MPG ?
I only fill my tank up when it needs refilling

 

on a recent trip to and from Asheville NC I saw 29.8 and 31.7 MPG respectively.. Sport mode (to keep temps low) and 99% 7th gear cruising with A/C on.. I thought that was ridiculous for a car like this.. (all stock except BMC air filters)

 

That's pretty impressive with the A/C on... I assume this was your 991.1 GTS ? Also, I always heard that the higher temps in normal mode were to increase gas milage?

 

I was doing an experiment to measure fuel consumption in order to assess the condition of my motor... i.e., higher gas milage and lower operating temps mean I'm getting more power and efficiency out of my engine. In that regard, I was looking for comparisons with similar cars.

 

yes on the 991.1GTS
Wife was following in her 958 GTS and she got 20.7 and 21.3 (drive to and from Asheville )..(cayenne was loaded to the brim)

I have a bad habit or turning A/C off when stuck in traffic, in drive through etc.. some OCD regarding car temps .. dont know where it started.. may be watching my dad cycling his A/C on his beetle and older cars lol

 

How do you get to that screen on the PCM?

 

Press the "CAR" button by the radio button. You can see it in my photo.

 

Track days are interesting. Somewhere under 1/2 tank ...near 1/4 tank, the "you need to refuel" warning pops up, with the red light. It's pretty annoying because it pops up over the Sport Chrono screen! Once you start driving 'normally' there is at least 100 miles left in the tank.

 

if ur worried about mileage U need to get a Hyundai or equivalent..I fill up at 1/4 tank, could care less about mileage..

 

did not see a single post that indicated "worrying" or concern about MPG

the point that may have been lost, is admiration at how versatile these cars really are..

 

do U have a hard on for me,,last time u posted about my ramblings and used curse words,,,others apologized in ur behalf for being so rude,thats not acceptable on any forum..