Transmission gear shift indication techniques

A method, comprising:

• determining, at a controller of a vehicle powered by an internal combustion engine, the controller including one or more processors, whether a gear shift of a transmission of the vehicle is occurring, wherein the transmission is a manual transmission or an automatic transmission operating in a manual mode;
• determining, at the controller, whether both an engine speed and a vehicle speed have not changed by more than respective predetermined thresholds during respective predetermined periods in response to determining that the gear shift of the transmission is not occurring;
• calculating, at the controller, brake specific fuel consumption (BSFC) for each of (i) a current gear of the transmission, (ii) a lower gear than the current gear of the transmission, and (iii) a higher gear than the current gear of the transmission, in response to determining that the both the engine speed and the vehicle speed have not changed by more than respective predetermined thresholds during respective predetermined periods;
• determining, at the controller, which of the current gear, the lower gear, and the higher gear has a smallest BSFC to obtain a desired gear for the transmission;
• and
• outputting, from the controller, an indication to shift the transmission to the desired gear when the BSFC for the desired gear is less than the BSFC for the current gear by greater than a predetermined threshold.