nissan gtr dct

What is the difference between AMT cars and automatic cars?

Stands for automatic manual transmission.... Further I would like to highlight the differences between all the available 'automatic' transmissions in the market today - AMT , DSG , CVT and triptronic. Firstly the main difference between a conventional automatic and these newer automated manuals/DSG is the way the power is transmitted from the engine to the transmission/gearbox. (A)In a conventional automatic, there is a torque converter that transfers power from engine to gearbox. Additionally, they have a planetary gearset which is different from a conventional manual gearbox.The low and higher gears in these are usually controlled with hydraulics wheres in a triptronic you use electronics to control the hydraulic valves. Advantage and Disadvantage ? There is no clutch to replace which makes it relatively inexpensive to maintain.The units are sealed and would require very little oil change for a long time. They are quite slow to respond and inefficient (B) On the other hand in automated manuals there is a clutch or rather 2 clutches ( in DSG there is one for even gears and another for odd gears). The way the power( torque actually) is transmitted is the same as it would in a manual gearbox with the one differnce being that the computer does the clutch/de-clutch and shifting action for you based on a algorithm. Some examples of the AMT or single clutch automated gearbox would be the gearbox in older Ferrari of the 90s to early 2000s, Bmw's SMG , Lexus LFA , All Paganis, Lamborghini Aventedor and formula 1 ! Pros and Cons: The advantage of this being the light weight ( at times 50 kgs lighter than dual clutch) but one does get the jerky shift which is why more and more companies are going over to the heavier and complicated but much smoother dual clutch. (C)Talking about the dual clutch now the examples would be the DSG( VW) , Nissan GTR , new Ferrari , the new Lambo Hurracan, ford fiesta DCT(in india) Pros and Cons: As mentioned , they are more expensive to produce and add weight but are the best in terms of driveablity and performance(fastest shifts) (D) Now the third type would be CVT which does not have gears at all !(technically speaking, they have infinite gear ratio).The gear reduction in this case is with a set of belt drives. They may or may not have a torque converter to transfer torque. This in theory would be the most efficient transmission as they help keep the engine at the RPM in which produces the most FE or the most power, atleast that's the theory anyway! So that's the major differentiation between them all . To talk about this particular car , it has a single clutch like I mentioned in (B) . It would in theory be just as efficient as a manual but smoothness and driveability depends a lot on the calibration performed by the company. While they work brilliant in a track and while driving fast , they are quite jerky in city bumper to bumper traffic