alt Hacker Newswhy slushbox is bad for fuel efficiency
Automatics have been more efficient than manuals for decades. And the computer can shift a DCT faster than you can. These days a manual tranny is right up there with hand-crank starting your car: if you enjoy it, great, but don’t get smug because people don’t want to manually adjust the spark advance.
Replies
bluGill • today at 3:21 AM
Only because they cheap out and don't put in manual with optimal gear ratios. Otherwise the manual is better because you can use high throttle with low rpms - try that in an auto and you get high rpms which is bad for efficiency - but great for acceleration.
>Automatics have been more efficient than manuals for decades.
No, they haven't. At least, not ones the average consumer could actually buy.
While it's true that modern 8 or 10 speed automatic transmissions do now compete favorably with 6 speed manuals, the former didn't meaningfully exist in passenger cars or trucks until around 2017. Neither did DCTs outside of high-end brands- sure, they're starting to do that now that "torque converter loss" means they don't pass emissions, but that was an option that commanded a premium back in the mid-00s when they were introduced (and still not actually more efficient than a manual outside of shift speed).
An automatic with 4 gears is less efficient than a manual with 5, much less 6 (this was the standard until about 2010 or so); one with 6 gears is likely on par with the 5-speed manual (and loses to a 6-speed, obviously).
So no, "decades" is bullshit. It's a very recent advancement.