Still barely getting 18 mpg. I dunno what's goin on. I'm about to install a new engine air filter today so we'll see if that helps.

 

2005 s2000, Consistant 26MPG hear...and i drive city like a mad man.
Oh and i used to get consistant 17mpg in my cammed Formula Firebird.

 

The S2000 gets decent mileage compared to compact sedans, such as: VW Passat, BMW 328i, Honda Accord. Not quite as good as Civic or Corolla. An engine can have either of two types of efficiency: volumetric efficiency, or thermodynamic efficiency.
The former applies to the amount of work obtainable from the engine per unit of displacement volume. The S2000, as we all know, is phenomenal in this regard, and tops all commonly available production normally aspirated engines. Not too many turbos even top the S2000.
The latter applies to the amount of work produced per unit of fuel consumed in the combustion cycle. The S2000 is reasonable, but not outstanding, in this category.
From a powerplant design point of view, volumetric efficiency and thermodynamic efficiency are contrary goals. They cannot both simultaneously be outstanding. Our s2K's strike an excellent compromise.

 

I've had 3089.3 miles so far, at an average of 27.0mpg.

Standard deviation per tank is 2.9mpg, with a low of 22.7 and high of 32.2.

The 22.7 was an autox day.

Not bad for a 9 year old car =)

 

i'll write in here the same thing i wrote in the UTH section:
lets calculate:
lets assume we are located here in california where the price of gas is royally a bitch and is super expensive...
if the price of premium fuel (91) is at 4.69 a gallon for premium
the price of mid-grade (89) fuel is at 4.49
and the price of regular grade (87) is 4.39

the difference between 91 and 87 is 30 cents.
the difference between 91 and 89 is 20 cents.

30 cents more than $4.39 is a difference of 6.83%
20 cents more than $4.39 is a difference of 4.26%

that being said, i want to say that in conclusion, its not worth it to get 87 octane gas for your 91 grade ONLY S2000 because the difference in price between 91 and 87 or 89 is now SO insignificant due to the VERY high gas prices.

just a thought

 

i like how you include the standard deviation

in that case i get an average of 26 mpg, with a standard deviation of 2 mpg

 

I should also mention which tanks are 91 and 93 octane, but I'll spare you. Definitely more butt-power on 93, and almost 2mpg highway average for the same priced gas.

93 is the way to go if you have it =D

 

My 2008 S has only about 1,000 miles on the clock. I did measure my mileage for the first time on the last tank. My commute is 33 miles highway but it takes 75-90 minutes on average so, you can see it's stop n go in heavy traffic. That tankful measured 22.998 MPG. I don't think that's bad for a new engine in heavy traffic.

I haven't had the chance to measure highway mileage but I can believe 30 mpg at 65 mph in 6th.

 

after owning a couple of new cars, in my experience new engines are more gas efficient... i dont know if its just me

 

I would think that has more to do with the driving habits of a new engine vs that of a broken in engine.