Originally Posted by
Sydneykid
No matter how "efficient" they get, torque converters always allow some rpm differential between the engine (higher) and the driven wheels (lower) some of the time. It is really the only reason for a torque converter to exist, to allow for that rpm difference. Which inevitably means more fuel is being used (less efficiently) at those times. Also less efficient is their shift speed, they can never remotely approach the gear change speed of a DSG that has preselected the next gear. In comparison, to facilitate the gear change, the auto has to unlock the torque converter, which being a fluid coupling is not rapid. Even less efficiency is evident in the torque converter auto due their engine braking ability compared to the direct connection of a DSG.<br>
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Engine wise I'm not sure it matters how much power they have or have not, a DSG will always transmit more of that power to the driven wheels more of the time. There is a real reason why they are utilised in almost all forms of race cars, where transmission power loss is unforgiveable. For the same reason GTi's and R's are staying with DSG's, performance.<br>
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BTW Packards had lock up torque converters in 1949, the common Hydramatics had lock up torque converters in 1981.<br>
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Personally my view of VW's Australia's decision (if they have in fact made it) has nothing whatsoever to do with efficiency, power or fuel economy. More to do with warranty claims, perceptions of the reliability of DSG gearboxes and customers expectations when they buy an "automatic".<br>
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Cheers<br>
Gary