[ChazInMT]

By throttle, I mean the throttle position at which the engine is creating 70% of its power....not necessarily 70% of the travel on the gas pedal range of motion. We all have driven many types of cars and unless your braindead, you've noticed on some, you mash the gas pedal a tiny bit and yer moving on out (GM seems most like this) but others, you have to practically put your foot through the floor to get moving (I think Ford). Not saying one is better than the other, just different.
70% Throttle is 70% load, you're either slowing down climbing a cliff, going steady state up a very steep hill, or as is usually the case, you're accelerating on flat ground. I'm not saying you're going to cruise at 70% throttle, this is just the place where the engine is most efficient. This is why Pulse & Glide works well. The throttle position is the same as load since a governor is not in operation on cars. And if you look at 80% of the BSFC curves, 2500 RPM is in the middle of the island. You infer 2050 RPM is the middle of the island by saying 1600-2500 RPM. For large displacement engines and diesels, 2050 RPM may well be in the middle of the sweet spot, but for most smaller displacement gas engines, it seems like 2500 is the number. Technically, load is always 100% for any given throttle position, it is all just a matter of what the vehicle is doing with the power provided.