Official JDM BRZ weight and MPG
 

http://i.imgur.com/SNDDv.png

1230 kg = 2706 lbs
12.4 KM/L converted to MPG is 29.17.

http://www.subaru.jp/brz/brz/spec/spec.html

pretty good, but i was expecting at least 35. i mean that what DI was suppose to be for.

i wonder if its an average of city/hwy. Why do the different specs get different MPG rating.

13.4 for RA. and 12.4 for the S

Because the lower grades weigh less.

40 kilos lower mpg by 2.5? Hm.

Here:
Pretty harsh test, if you ask me.

Its also a different final drive ratio for the open diff vs LSD

Notice the test doesn't spend much time holding speed, so the higher diff ratio isn't making much of a difference. The frequent stopping/starting means the weight will matter much more as you can see. On the highway, the diff ratio will determine the cruising efficiency, which I predict to be pretty low. Hoping Toyota changes the 6th gear to 0.62 ish for a 2200 rpm cruise on the 4.100, 2000 on the 3.727, or even lower.

Oh and another thing to note is that the faster the car, the more it is hurt on a test like this because the acceleration is pretty leisurely (to accomodate the slow cars).

For more extreme gas savers, the good thing about a 2.0L engine is the idle consumption is low so you can pulse and glide with the engine on and get a very high mpg number.

If you read the notes on Subaru's website, the fuel mileage information becomes a tiny bit more clear.

RA 6MT = 13.4 km/L without A/C, 13.0 km/L with A/C (16" Wheels, 3.73:1 Final Drive)
R 6MT = 13.0 km/L (16" Wheels, 3.73:1 Final Drive), 12.4km/L (17" Wheels, 4.10:1 Final Drive)
S 6MT = 12.4 km/L (17" Wheels, 4.10:1 Final Drive)

Jeff

Well it looks like these figures are for city driving, not highway like we were assuming, based on the JC08 spec. So in a 20 min session with 10 stops and starts, less than a minute of sustained highway(ish) speed and plenty of acceleration (albeit slow acceleration) 29.2 mpg is quite impressive. I'm trying to find two equivalent cars to compare JC08 vs EPA ratings, which is hard when you can't read Japanese.

Edit: I guess I was wrong. The 2.0L SKYACTIV Mazda 3 gets 38mpg from the JC08, which is almost exactly it's EPA highway rating (39), so now I'm just confused. I need to stop speculating. It's way too frustrating.

Isn't the JDM motor quite different from the US on the SkyActiv Mazda 3 though?

I have no idea how JC08 compares to the EPA testing, but that may be a bad example. I recall the compression ratio at least being significantly different but I may be wrong (on the US vs JDM Mazda 3 SkyActiv).

The US one has lower CR because US fuel quality has some issues or something.
It's hard to compare these tests but yea the 86 isn't doing as well in economy as it could be. Hard to say why. I'm curious what this scores on the EPA test because you'd think CAFE standards would prompt them to try to do better, if this only get say 31mpg (for CAFE calculation, I don't remember what that is exactly), then even with its small volume it poses a pretty big threat to the 39mpg small car requirement.

Because the higher modesl will also have a better air flow and under car air flow thing.

and 12.4km/l = 8.1l/km pretty decent.

Also note that the boxer configuration is inherently less fuel efficient than an inline configuration for some reason.

I forgot about the lack of underbody panels on the RA. But all you really have to do is buy some corrugated foam board and tape it to the bottom...

No, boxer is not inherently less efficient. Subaru's EJ engines were just really old and inefficient by design. If anything, the better balance would make it more efficient due to slightly lower friction.