Shift time

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Shift time refers to the time interval between gear changes in a transmission during which power delivery is interrupted. This is usually in reference to motor vehicles but can apply to any gearbox. Reducing shift time is important in performance vehicles or race cars because during shifting the vehicle is rolling without power to the wheels. Shift time in a manual gearbox is dependent on the driver but in automatic or semi-automatic cars the electronic mechanism must be tuned to minimize the time between gears.

One method of drastically reducing shift time is to use a Direct-Shift Gearbox which has two independent clutches that predict the next gear change making the shift time very small. Using a freewheel may reduce shift time as it may not be necessary to use the clutch. A shift kit is also intended to reduce the shift time of a manual vehicle. In simple terms, a DSG is two separate manual gearboxes (and clutches), contained within one housing, and working as one unit.It was designed by BorgWarner,and was initially licensed to the Volkswagen Group, with support by IAV GmbH.[citation needed] By using two independent clutches, a DSG can achieve faster shift times (8ms) ,and eliminates the torque converter of a conventional epicyclic automatic transmission.

In a manual transmission car, shift time for upshifts can be reduced by installing a lighter flywheel. During an upshift the engine speed must fall for the same vehicle speed; a lighter flywheel will allow the engine speed to drop more quickly when it is unloaded leading to shorter shift times.

Shift times[edit]

  • A long shift time is considered anything over 625 ms[1]
  • The average manual car driver: 500 ms - 1 s (vertical gear changes e.g. 1st-2nd, 3rd-4th, 5th-6th): 1s - 2s horizontal gear changes (2nd - 3rd, 4th - 5th, 6th - 7th). As well shift times can change depending on gear throws (distance between gears), its easement of movement, ergonomics of lever and age of gearbox.[citation needed]

Gearbox shift times (Fastest to slowest)

See also[edit]

References[edit]

  1. ^ "Tech Tips: Understanding TAP". Automotive Service Association. Retrieved 2006-07-29. 
  2. ^ a b c d e f g h i j k l "Volkswagen DSG". 
  3. ^ "Alfa Romeo UK". 
  4. ^ "Ferrari FXX Breaks Cover". Piston Heads. Retrieved 2006-09-23. 
  5. ^ "New Clio R.S. 200 EDC: ‘à la carte’ sports performance". Renaultsport. Retrieved 2014-03-09. 
  6. ^ "2012 Chevrolet Camaro ZL1 - Staged Up Shifts". SupercarHall. Retrieved 2012-02-23. 
  7. ^ "Audi TT Review". Evo Car Reviews. Retrieved 2006-07-29.