Dual Clutch

Hi I have yet another newbie technical car question. It regards a dual clutch. I just want to know if it is a manual (that would make no sense) pure automatic, or tiptronic/shiftronic/whatever each car company calls it. How does it work? how does it make you car better? Is is expensive? any information or links would be helpful...thanks

it basically selects the next gear and then when the computer tells it to it engages it. with these you have about the same hp losses as you would have with a manual but since there are more gears and 2 clutches it allows you to stay in the powerband while it shifts without ever taking power off the wheels.

i could be wrong on this but im pretty sure thats how it works.

i think the audi web site has an explanation.

Audi also has a system using two input shafts into the transmission. Half of the gears are on one shaft (1,3,5), while the other half are on the other (2,4,6). It uses dual clutches and can almost instantly shift up or down at the flick of a switch. All solenoid controlled.

Porsche used a similar design in the past but abandoned it due to gremlins IIRC. Their tiptronic is nothing really more than an automatic tranny w/ semi manual override.