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      09-21-2019, 07:25 PM   #10
Redd
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Drives: 2010 BMW E92 M3 Dakar Edition
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Fully automatic refers to a gearbox that does all the shifting for you. Think of the automatics in older cars with just the P, R, N, D, 1, 2 options. Semi automatic refers to a gearbox that also gives you the option to select your own gears but does not require you to use a clutch pedal.

Fully automatic cars with a semi-auto mode have been around for a long time, with various methods of gear selection. Some use a gated shifter like the Alfa Romeo Q-system (uses an Aisin gearbox). Nowadays nearly all automatic cars have paddle shifters to give you a semi-auto mode.

This is different from the actual type of gearbox mechanism. Traditional auto gearboxes used to be torque converter gearboxes. Then they added buttons or paddles to introduce a semiautomatic mode to torque converter gearboxes. Tiptronic falls in this category. After that came the robotised manuals (aka single clutch auto) which was basically a manual gearbox with a computer controlled actuator which worked the clutch for you. BMW SMG, Alfa Selespeed, Ferrari F1, fall into this category.

Then came the dual clutch gearboxes, pioneered by VW. BMW DCT, Porsche PDK are dual clutch gearboxes, with complex gear trains with two clutches, each operating alternate odd/even gears, to allow faster shifting.

Of late there's been a renaissance of sorts for the old torque converter automatics, led by the new ZF 8 speed that's found in many of today's high performance cars. Make no mistake, this new ZF has a torque converter like in the automatics of old, but has been tweaked to shift as quickly as a dual-clutch while retaining the reliability and ability to handle power like a torque converter.
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