I just did a 250 mile trip each way this past weekend in my '05.supercharged C2S and was getting on it. Had the cruise set at 88 MPH for a lot of it (trip computer showed an overall avg of 78 MPH) and averaged 20.5 MPG. The RUF supercharger is s centrifugal version with engagement clutches, so when the car is cruising along, the supercharger can actually disengage. As soon as you put your foot back into it the clutches engage, connecting the kompressor impeller to the belt driven pulley compressing the induction air. So it's an interesting design that in some ways works more like a turbo - doesn't have the constant parasitic drag on the motor, but still the advantage docs supercharger where you don't have to build boost from exhaust velocity. The one downside is that there are clutches, which are a wear item that need renewing from time to time. Anyway, I digress....

Wife's '05 C2S is her DD and hasn't done much if any highway time of late. I just checked - it's showing an avg of 20.1 mpg so yours does seem a bit low.

 

give me a break
who cares
enjoy the fking car bro

 

As stated before, in CA we get two blends...we just changed to the winter blend which is "oxygenated" so it's better for the environmentalists (sarcasm). When this hits the pump the fuel mileage drops a good 10% as does the power output, how much, I don't know but you can feel it.

However my typical numbers on the "regular" blend is:

HWY; 25-26
Combined; 17.5-19
Track; 8

 

lol@ MPG, i've never looked or cared to look...its nothing bad though, so who cares!

 

Right foot??


I normally get combined 19+ driving to/from work daily. If I get a little crazy or turn Sport Mode on then I see a drop to the 17's.

 

I doubt most of us care. TC asked a question, and we answered.

 

Took your advise and drove the car about 50 miles to my fams house in the burbs. Mostly highway but, a bunch of city and suburb driving. I reset my MPG meter and I averaged 21+ round trip!

 

Great! Now find a long curvy road and try to get that gas mileage back under 15 Have fun out there.

 

I reset my trip every time I fill it with gas. Highest I've seen is 19mpg which was mostly highway. Daily commute is in the 13-17 mpg range.

 

My 2007 C4S gets as low as 12.X/MPG driving around Los Angeles in regular slow city traffic. YES, it freaked me out the first time I used half a tank in 100% city traffic and found the low MPG

I average around 17.X city and hwy driving.

Highway miles I get over 21.


Your MPG appears to be normal.

 

I only asked because my previous two 911's were closer to 17 mpg with the same driving I do now. I "CARE" only because I wanted to make sure it wasn't a mechanical issue. Thank you all for the replies.

 

Heh heh. Then there's the guys who don't care how much dealer charges for an oil change because after all it's a "Porsch" Warped sort of badge of honor I guess.

 

Around 17.4 mpg avg

 

I hover around 18 mpg. That is with a heavy foot.