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Comment by kindall | Hacker News Reader

Subaru CVTs already have essentially this feature. The transmission doesn't have gears (duh, it's continuously variable) but it still has the ability to manually shift to predefined ratios.

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And it's horrible. I was a dedicated manual driver, but 3 years in an Outback with CVT and flappy paddles - it's miserable as an analogy of shifting. You can trigger several "down shifts", but there's some elastic feel in the system that doesn't convert to slowing the car via engine revs or give the feeling of immediate power. I gave up on the paddles early on.

Their CVTs also use these simulated gears during normal automatic driving, presumably just to make it feel more like a traditional automatic (which it mostly does, to my untrained senses). Apparently this is important to the car-buying market, although I don’t understand why.

Car reviewers love to complain about how a CVT lets the engine rev up to high RPMs and just stay there the whole time you're accelerating. Which is of course the entire point, but some people apparently prefer that their car spend lots of time at suboptimal RPMs, probably so that they don't have to break the habit of flooring it unnecessarily.

It's completely subjective but it just sounds wrong. Like being in a car with a slipping clutch. Apparently enough people feel the same the it's easier to fake real gears than change the market.

According to physics an ICE is most fuel efficient at 90% throttle and low RPM. At high RPM, or lower throttle positions you lose efficiency. So if you want maximum fuel efficiency you need to put the throttle to the floor, but stay at low RPMs. Thus the CVT is not doing the right thing for fuel efficiency. (though I'm not sure if the difference is worth measuring)

Obviously the exact numbers varies a bit from engine to engine.

When you put the pedal to the floor, you're not trying for efficiency, you're trying for power.

Dropping to lower RPM for efficiency is what happens when you're done accelerating and ease up on the pedal. That's not what people complain about with CVTs. The complaints are about behavior and sound during acceleration, not after acceleration when you are merely cruising on low power output.

That might be you, but not me. I'm always trying for effiency. My cars never have the acceleration to make power interesting. I'm weird, but whatever.

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