Hello Everyone Now i am in BTech 2ed Year . When i should start for study for CAT.

Hello,
It depends on you when you want to start it. If you think you have to start if from the basics and need to put a lot of effort then you can start it from now also. And if have your basics clear then you can start it from 6-7 months before the exam and can check your preparation by giving mocks. If you start from now then  just 2 hrs a day for cat preparation is more than enough for you.

Hope it helps you. Good luck