If an engine with high horsepower can gear down to increase torque, couldn’t a high-torque engine be geared up to increase horsepower?

Question

Just wondering why, in these discussions, people always say the former and not the latter.

In: Engineering

Answer 1

No. Horsepower does not change when geared up or down. Or, at least, peak horsepower doesn’t.

This is because horsepower is more or less torque times speed, and horsepower is conserved while torque and speed can be exchanged.