|
Engines typically have higher BSFC at moderate or higher loads for a given RPM, as outlined by the map Ecky posted. That doesn’t mean less fuel useage, but that they are producing a given amount of power using less fuel. It would be preferable to just require less power, but absent that if you make your gearing taller your engine will be turning less RPMs. As power is a function of RPM, if power requirements (load) are fixed, the lower the RPM the more torque you will require at that RPM to produce the same power. This is good as your engine loading (torque required @ RPM/available torque @ RPM) is increasing and your BSFC is improving. If you continue down that path, eventually you will go to far in that your engine will not produce enough torque at that RPM to keep up or you will cross over your BSFC sweet spot by over lugging the engine. I believe based on your posts you have already figured this out, as you want a torque down low engine combined with tall gearing.
|