Sports Differential discussion
08-31-2011, 01:23 AM
#21
Some info:
This car is a Euro, so it has the 3.0T badge on the rear, likely an '09 though as it seems to have the HUGE side mirrors, but is an S4
- The car does not have Sport Diff, with SD you can nail the throttle and 100% of the TQ would go to the rear tire on the pavement.
- The F/R TQ split is not 50/50 it's 40/60.
- The SD is both a mechanical and electrical diff, as shown in the video, it has a gearset that drives the clutch plates on each side 10% faster than the axles, and the computer can use the clutches to grip the plates, and transfer as much as 100% of the TQ to one side or the other (within tolerance limits, if you really want to know where that limit is I will dig it up, but I don't recall the TQ limit off the top of my head).
This car is a Euro, so it has the 3.0T badge on the rear, likely an '09 though as it seems to have the HUGE side mirrors, but is an S4
- The car does not have Sport Diff, with SD you can nail the throttle and 100% of the TQ would go to the rear tire on the pavement.
- The F/R TQ split is not 50/50 it's 40/60.
- The SD is both a mechanical and electrical diff, as shown in the video, it has a gearset that drives the clutch plates on each side 10% faster than the axles, and the computer can use the clutches to grip the plates, and transfer as much as 100% of the TQ to one side or the other (within tolerance limits, if you really want to know where that limit is I will dig it up, but I don't recall the TQ limit off the top of my head).
Are you sure about the 100% TQ split.
If i remember correctly , that feature (sport diff also assists driving away) came first with the A7/RS5 (the ones which also introduced the crown diff and the full torque vectoring quattro, with brake assistance ala BMW). Other models should/could get it later (maybe the FL A5/S5 already have it)
08-31-2011, 06:31 AM
#22
AudiWorld Super User
Certain about the TQ split, with just the Torsen only it can move only 80% to the rear, but with ESP it can move all of it. The B7 RR4 was the first chassis to move from 50/50 to the 40/60. The RS5 with Crown Gear can move more TQ to the front over the the Torsen v3 we have. Audi developed the Crown Gear, and will stop using the Torsen soon.
Here's some good overview of quattro and how it has progressed over the years
http://en.wikipedia.org/wiki/Quattro...l_drive_system)
Here's some good overview of quattro and how it has progressed over the years
http://en.wikipedia.org/wiki/Quattro...l_drive_system)
Last edited by NWS4Guy; 08-31-2011 at 06:36 AM.
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