P&G Questions

[dosco]

Originally Posted by monroe74

Thanks for reminding me where to find that article. I think it's very helpful.

It is. I found another link to a very long paper that expounded on the graphs at the speed site. I'll dredge it up again, if interested ... but it basically says the same thing as the speed article.

The graph doesn't say that 3200 RPM is highly efficient "regardless of load."

Perhaps my choice of words wasn't so great, but the graph clearly shows that at the various load conditions (25%, 75%, 100%), the most efficient rev range is 3,000 to 3,500 or so.

I agree with you, though, so no argument.

For almost all modern cars (even with low-power engines), if we assume a flat road and a vehicle carrying only one or two people, then full throttle (or 70%, if we want to take the open-loop issue into account) is enough to produce acceleration, even in top gear.

Indeed. The very essence of P&G driving. I think we're in agreement.

Life is much more complicated with an automatic. It's probably brisk because your tranny decided to downshift.

I used to drive a stick, and am very conscious of what the auto trans is doing - thus my focus on both RPM and throttle angle.

I think the "brisk" part is b/c I've been driving with small throttle openings and low accelerations for so long that it seems very odd to be "flooring" it (not literally) and accelerating briskly.

Theoretically, we want full throttle 100% of the time, except when we're coasting.

This is where a CVT for a gasoline+spark engine comes into play... ...