[orange4boy]

CVT's are so much easier to understand. Here's my attempt at manual tranny shifting for best efficiency. Assuming accelerating to top gear and then cruising at X speed. Corrections welcome.

The goal is to create all your energy most efficiently. Never mind the dogma about shift as low as possible. That's the correct method once you are at steady speed. Gears mostly just change the power/time ratio. The limitation of gears is really just a function of the RPM at which engines operate.

Accelerating is the act of creating mechanical energy (HP/time) which is "stored" as kinetic (speed) and potential (top of hills). RR and Drag eat away at this but we will leave that out for now. Accelerating faster in and of itself is not more or less efficient than accelerating slowly.

Power is inversely proportional to acceleration:
100hp 1000lb car:0-60 ~20s
200hp 1000lb car:0-60 ~10s
400hp 1000lb car:0-60 ~5s
Theoretically, anyhow.


In a lower gear the "lever" the engine is acting on is longer so it simply applies it's work faster. Therefore, you should shift only when you will end up in the best bsfc range of the next gear. If you shift too early and end up "off the island" then you will create that energy more slowly at lower BSFC until your RPM gets into the sweet spot.

Is that about it?

I'm just now getting my head around this. I have always thought that accelerating faster to X speed requires more energy but it really only requires more HP which is energy over time. In the end it's still the same amount of energy to get to X speed.