I get around 20 combined city/highway combined in an 87 951.

 

Slightly OT but..meh..wanted to take the 924 GTS wannabe on a 600km ride today but it rained so i took the passat instead. I drove mostly on the highway at around 100mph with AC on for half of the trip and got 36mpg out of the whale. That with three people inside and no economy driving.

 

If i stay out of it, I average ~30 mpg on the highway in my 86 951 if I run pump gas. I'm running stand alone though and run at 17:1 AFR on the highway. Its actually not too much worse in the city, maybe like 25 mpg. Now on boost....I can almost see the fuel gauge dropping lol..

 

I find the easiest way to check y consumption is this:

Hit the tripmeter button when the idiot light comes on
Check the tripmeter reading when I fill up

That way I am getting a reasonably consistent reference point and the tripmeter means no maths required.

Oh, and I know I can go 100km from idiot light to fumes...

Cheers,
Mike

 

I took my 944 from Albuquerque to Chicago again last month, went via Colorado then across on I-80 (blah...). On the same trip (and others) in the past I've gotten high 20's, like 28 or so. But I was shocked, this trip I got 32, 34, 29, and finally 28 on successive tankfuls. Cruising at 70 for the most part.

 

Around 23mpg, or 10L/100km.
Don't see a proper highway, much. Mostly drive on single lane mountain roads.

 

Another nice old thread revived...
21 city/29 highway at 65mph commute.
Autothority chip, headers and no a/c running.
Shell 93, Rotella 15/40, Techron bi-monthly.
I only fuel 10 gallons per fill to save the 60 lbs.