Good input folks! I was wondering how folks with modifications to the engines were doing on fuel efficiency but I hadn't considered tires. Another note or two on my experiment; varied terrain on the ride with hills and flat spots, but mostly hilly (but not as hilly as West VA). Original tires yet and stock engine. I thought about taking the car out of gear and coasting down hills, but opted to leave it in 6th gear and on cruise control.

 

Try 100% city driving and you won't be. My mileage easily shoots to 30 when all highway. As always, driving style matters a lot.

 

The best mileage I ever got on my '02 S2000 was 33.1 mpg driving through Oklahoma at 65-70 mph with A/C on and soft top up. That was when the car had about 18k miles and was 100% stock using 93 octane gas. Tires were Goodyear Eagle RS-A: AP1 stock size at 32 psi.

 

11-13 average, stage 1 pulley CT supercharger. Don't drive that fast at all. Not sure if that makes sense

 

80% of my driving is "city" and I consistently average about 21 mpg. Even when I am absolutely flogging the car, I haven't been able to get worse than about 19.

 

last year when I drove to Richmond, VA it was a total of 360 miles on one tank. Filled it up and the pump clicked at 10.5 gallons

 

Just did my MPG calculations today; best was 27.85, worst was 23.21, averaging 25.64 MPG. Not bad for a 2-seater sportscar that's always fun to drive!

 

I get 100 smiles per gallon!