I get better mpg if I drive harder it seems. When I try and put around in low RPMs, it takes more fuel to get going. If I get up to speed quickly it seems to be less thirsty.

 

Engines are more efficient at higher rpms, but you do burn more fuel. Mabe you're in that zone where efficiency increases before mpg drops.

 

Lots of hidden factors too: one big thing is drag. A car that is less aerodynamic will be more affected by higher speeds, obviously.
Also, many people experience better MPGs in their S2000s when going ~75 versus ~60: a good explanation I've read of this is that the air/fuel ratio leans out the higher the revs go, so even though the car is working harder to fight the drag, the leaner fuel mixture gives it better gas mileage.
As stated, also depends on gearing/engine characteristics. Too many variables to just generalize in my opinion.

 

That hour over a 400 miles trip is definitely worth 6 dollars to me =)

 

One of the magazines tested this a while back in a BMW I think. They achieved the best mileage with short shifting and alot of throttle, not WOT but 5/8 or 3/4 something like that. With their computer data they found that puttering up to speed with light throttle application took too long; while it used less fuel at any given point in time, over the entire period it took get to running speed it used more.

That makes sense to me in the torque deprived S2000.

 

I hate to disagree but I believe it is the other way around. Engines are most efficient at lower RPM. By efficient I mean brake specific fuel consumption. So for the amount of gas in you get more out at lower RPM (in general). This is largely due to minimizing pumping losses at lower revs. This is why stationary engines are often large displacement, slow running engines.

 

I think Saki GT means efficient in power production versus fuel consumption over a period of time. With more load, WOT, and closer to peak torque the engine is producing significantly more power than it is dawdling along at low revs. Lower revs are typically out of the powerband of a 4-cycle engine, and the trade off in lost power is not made up for by better fuel consumption. The fuel consumption may well be significantly better but at 4000 rpm, in S2K for example, but you make only 100 hp. At 8000 you make 240 (no drivetrain losses). So at 4000 RPM do you get 60% better fuel mileage? There are too many definitions of efficiency, but we are all correct.

 

My thoughts exactly. Plus, its dangerous to do 60 on the interstates I drive on, you'd probably get rear ended.

 

If I had to improve my mileage I'd need a throttle stop to overcome my right foot!

Did you see that old Top Gear epsiode where Jeremy took a big diesel sedan (Audi maybe?) and drove the length of England at just over idle? He got some absurd mileage (hundreds of MPG) but it took forever and he was a rolling (barely) roadblock.

 

he didnt get hundreds of mpg. just drive in the right lane and chill out.