transmission swapping for MPG

[Bunger]

I've really got to stop coming by this site so much, all you guys have me thinking about lately is how to increase my MPG. =)

As far as taller gearing increasing MPG, I would think the greatest advantage would be in reducing the mechanical losses, mostly from the lowered RPM of the engine AND transmission (well at least the input shaft half). The ECU should also be able to better meter the fuel as there are fewer combustion cycles between O2 samplings (or more sampling per cycle, depends on the speed of the processor in your ECU).

Also, engines are normally most efficient at there torque peak (which is a good indicator of the engines peak VE). If you look at a CRX Hf, you'll see that the peak torque is about 2,000 RPM, right about cruising RPM.