Originally posted by Tr0LL
i actually have a b20b in my car... not a d-series.....
and i got around 28mpg with the p28...... but average about 30 with the ls (pr4) ecu......
the p28 ecu ran with the engine check light on though. it was for the vtec stuff (obviously because the b20b is non-vtec)...
Anyway, just weird how I dropped 10mpg. I mean timing can affect gas mileage, but 10mpg? that is a lot....
In your case I'm sure it was a combination of less fuel and more timing. BTW B series engines don't get the fuel mileage D series get b/c B series engines have more internal friction loss from having 2 cams and make their hp in the upper RPM area which doesn't spell high gas mileage, although I've seen B18bs getting low 30s in stock trim with a PR4 ECM - must be the extra torque down low. But anyways, low 30s to the gal is very respectable for a B series!