I only keep track if I go on a road trip and average about 24 mpg. At the track it is 4 mpg.

 

I'm a mpg data junkie, and this is 100% spot on for my 2007 C2S with 40k miles.

 

14,000 miles of driving, mostly canyon carving:
Best - 25.5 mpg driving it home 400 miles from the dealer
Avg- 18.6 mpg 10% fwy, 90% spirited diving
Cruising the fwy- 22.5 mpg

 

12.5 city driving. 20 highway. I'm probably 80% city so I average about 14 mpg

 

So far about 19-20mpg (12L/100kms) for my mixed commute. I find that the meter ticks up quite quickly when idling in traffic or at the drive thru (need my McDonald's coffee every morning on the way into work and don't want to deal with parking the car safely). I have yet to get it to average below 10L/100kms (23.5mpg) on a mainly highway drive, and higher than 15.5L/100kms (15mpg) for heavy-foot city driving in sport.

 

05 C2S - 21 mixed, 17 city, 25 hwy

 

2009 C2S 6 speed manual
15-17 mpg around town
24 was my best highway mpg.

 

93 Octane and 17.5 in spirited weekend driving. Never been in real stop 'n' go traffic.

Finished a run to Lime Rock and tearing up mountain roads in Berkshires. 450 miles of driving and averaged 19 per gallon.

Last year I easily boosted mileage by 1.5 MPG after a Royal Purple fuel treatment. There are a couple of good ones out there tested on independent dynos and in MPG tests that show a legit fuel system cleaner can add back a few lost ponies and add some lost MPG. I wanted to eliminate a little hesitation and be proactive about maintaining clean injectors for horsepower.

I don't care much about MPG, but love math and love tracking how some products do or don't work.
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08 C2S. Mixed driving with ave of 16-17 MPG. But who cares, because i get much higher SPG "Smiles Per Gallon!" With every fill up.

 

2008 C4s. 16.5mpg......all city driving. Not in traffic, but 40 mph roads.

 

I know that tracking Mpg seems odd for a sports car but I have found that it can be a good health indicator for the car. My previous E92 M3 dropped a couple of MPGs from normal so I knew something was wrong. Turned out that the thermostat was going bad. So like I posted earlier. I track it on known long drives for comparison purposes. Lower Mpg means lower HP. For a given route and driving style. On short trips I don't even look.

 

Twas a pretty good Fifth Gear piece on restoring lost power/MPG. I think they had a VR6 Scirocco, and after something like 75000 miles it was down like 13 HP from when new.

They did an oil change for 2 HP, an airfilter for 5 HP, a plug change for 5 HP and fuel treatment for another 3-4. It was along those lines, with them getting back to original spec HP and, of course, MPG was up.

Aside from peak HP gains, the power curve was better, too.

None of this is surprising, but we forget how little things all add up.

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2009 Carrera S 3.8,
44,000 miles, 17+ city, 27-ish on the highway at 75-80, best was 28.8

 

2006 C2S, Manual, 47k miles and counting, daily driving: ~18mpg city

 

16.1mpg city.