Quote:
Originally Posted by wparsons
An automatic has a torque convertor, and will always decouple slightly on deceleration.
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That may have been true 10 years ago but not anymore with modern automatics. Many "performance minded" cars that come with automatics come with a locking torque converter (such as the 86) that locks in accordance with vehicle speed. In our case, the TCM locks the converter at speeds in excess of 30mph (Source: 2013 Scion FRS Service Manual).
Toyota has been using this same method extensively in their Lexus line, BMW, Mercedes, Honda, Acura also use similar locking techniques.
Now while locking a torque converter to the output shaft of the impeller gives many of the advantages of a clutch you still have higher rotating resistance due to the presence of transmission fluid, under pressure, within the torque converter.
Perform this experiment with an auto and a manual FRS and you should see that the manual will coast in gear longer than an auto provided your speed is over 30mph. Of course, this experiment is a bit "flawed" all things being equal since there are obvious weight differences between the manual and auto as well as the taller gears of the auto will not send as much rotating drag to the rear wheels from engine compression.
Be careful making broad, blanket statements in front of car nerds.
Oh, and BTW, the presence of a torque converter is not what defines a transmission as an auto or manual.
Scott