A higher compression engine could get better mpg but I wonder if the poster is quoting mpg for Imperial Gallons which are larger than U.S. Gallons. I once accidentally set my trip computer (BMW) to Imperials Gals. and got AMAZING mileage for a short time until I found the mistake. Imperial is 20% larger.

That is about spot-on for a Euro SC. I've done tens of thousands of miles round Europe in mine and it always seems to average about 29mpg (that's British gallon) As for the constant 56mph I've never done that but it sounds possible.

100% highway miles 75-85 mph got 24.9 mpg, no a/c running. '88 3.2 no mods, engine rebuilt about 2 years ago. In town seems to drop to about 16 but that's 75% rush hour commute driving which I guess is not too bad.

On a trip south from a racetrack in northern Norway I managed to squeeze almost 33 mpg (7.2 l/100 km) out of my '84 3.2. That's only happened once. At the track, on the other hand, it was somewhat more thirsty, a little above 9 mpg (25 l/100 km). With a mix of city and slightly spirited highway driving I usually get about 23 mpg (10 l/100 km).

EDIT: For clarity, these numbers were calculated from odo readings between refills and are average numbers for one full tank of gas. Or as close to one full tank as I dared go before refilling.

/Peter

Some years ago, when our kids actually fit in the back seat, we took a trip from CT to NJ. So, with 2 adults, 2 kids, cruising at 75 mph, virtually all highway, we got 24 mpg. With a 21 gal tank, she is good for 504 miles.

Not to change the subject of this informative thread, but since the speedometers in at least the SCs are notoriuosly off by 10%, would that also effect one's actuall odometer. So if one has an indicated 130,000 miles, would that not be really 117,000 miles?

It is inaccurate to calculate mpg from the gauge reading, because the gauge is non linear. I am sure you have noticed how faster it drops after the half mark. The only accurate way to measure gas consumption is when you refill.

I have the same car... I was getting 17mpg. I jacked my car up and discovered one of my front calipers was frozen, not allowing the wheel to spin very well. I have a feeling rebuilding this caliper will significantly affect my mileage.