Just to change the mood around here I thought I would give the ones interested...
01-09-2006, 06:03 PM
#1
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Just to change the mood around here I thought I would give the ones interested...
Some excerpts from the article I just read in EVO on the amazing <b>Bugatti Veyron</b> and the development of its <b>DSG</b> gearbox.
Ricardo, a British company was contracted to develop and produce the unique seven-speed DSG gearbox, front and rear diffs for the AWD transmission and, crucially, its electronic control unit.
Originally the Veyron was going to have a paddle-shift automated manual like the Ferrari's F1 gearbox. But computer models predicted that the combination of <b>1g</b> acceleration and the sudden interruption of power when another gear was being selected would lead to a completely unacceptable jerk for both the driver and transmission.
Development was going well witha Veyron mule (disguised as a Diablo) pounding round MIRA, then in 2003 VW suddenly changed the design parameters.
Originally the engine was to be torque-limited in first gear, but VW announced this was no longer going to be the case. They also increased the tyre's grip value by <b>25%</b>, insisted first gear could run to <b>107Kph</b> (~67Mph) and re-calculated the car's kerb weight upwards.
It all meant a major rethink for Ricardo.
The specification of the steel used for the actual gears was changed to the ultimate, <b>"vacuum arc remelted steel"</b>, four times more expensive than any other type. This was necessary because the torque load during a launch at the rear axle could now reach a whopping <b>10,500Nm or ~ 7800 Ft/Lbs of torque!</b> This was now uncharted territory for a road car.
They ended up with a dry sumped (a first for a road car), seven-speed gearbox with casings made of high-grade aluminium (magnesium wouldn't be strong enough). The gear box needing four separate oil pumps to lubricate the twin clutches and gear clusters, with the multi-plate wet clutches (which should never need maintenance) being doused in up to <b>35 litres of oil/minute!</b> The whole gearbox assembly ended up weighing just <b>122kg</b> (268Lbs) of which <b>22Kg</b> (48Lbs) was the clutches.
The gearchange takes just <b>150 milliseconds!</b>
Ricardo, a British company was contracted to develop and produce the unique seven-speed DSG gearbox, front and rear diffs for the AWD transmission and, crucially, its electronic control unit.
Originally the Veyron was going to have a paddle-shift automated manual like the Ferrari's F1 gearbox. But computer models predicted that the combination of <b>1g</b> acceleration and the sudden interruption of power when another gear was being selected would lead to a completely unacceptable jerk for both the driver and transmission.
Development was going well witha Veyron mule (disguised as a Diablo) pounding round MIRA, then in 2003 VW suddenly changed the design parameters.
Originally the engine was to be torque-limited in first gear, but VW announced this was no longer going to be the case. They also increased the tyre's grip value by <b>25%</b>, insisted first gear could run to <b>107Kph</b> (~67Mph) and re-calculated the car's kerb weight upwards.
It all meant a major rethink for Ricardo.
The specification of the steel used for the actual gears was changed to the ultimate, <b>"vacuum arc remelted steel"</b>, four times more expensive than any other type. This was necessary because the torque load during a launch at the rear axle could now reach a whopping <b>10,500Nm or ~ 7800 Ft/Lbs of torque!</b> This was now uncharted territory for a road car.
They ended up with a dry sumped (a first for a road car), seven-speed gearbox with casings made of high-grade aluminium (magnesium wouldn't be strong enough). The gear box needing four separate oil pumps to lubricate the twin clutches and gear clusters, with the multi-plate wet clutches (which should never need maintenance) being doused in up to <b>35 litres of oil/minute!</b> The whole gearbox assembly ended up weighing just <b>122kg</b> (268Lbs) of which <b>22Kg</b> (48Lbs) was the clutches.
The gearchange takes just <b>150 milliseconds!</b>
01-09-2006, 06:36 PM
#5
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True enough, the SMG II is the fastest shifting gearbox but its smoothness is not that great...
The DSG gearbox as already been hailed as the best, and smoothess performing auto/manual box in the automotive world and this of by many car experts and car magazines.
Again to quote the EVO article <b>"That seven-speed DSG gearbox is one of the finest pieces of engineering I've ever sampled in a car, period".</b>
Again to quote the EVO article <b>"That seven-speed DSG gearbox is one of the finest pieces of engineering I've ever sampled in a car, period".</b>
01-09-2006, 07:22 PM
#7
Actually DSG is the fastest shifting gearbox.
<ul><li><a href="https://forums.audiworld.com/a3/msgs/39193.phtml">https://forums.audiworld.com/a3/msgs/39193.phtml</a</li></ul>
