No, 'you need to' does not imply future. It implies now. And if it is your boss speaking, it MEANS now! Conversely - You'll need to implies that you can leave it for a while. We have a thing called a WOF - where you need to get your car checked regularly. At the station - the inspector could say: 'You need new tyres' - I will not certify your car until you replace them. 'You'll need new tyres' - The tread is getting thin. They are legal now, but I am warning you that you won't pass your next test.