No power til tubo kicks in
 

I have a 2001 BMW 530D. I have hardly any power until the turbo kicks in. Anything can beat me from a standing start, I am left standing at traffic lights. I have to reall press down the accelerator to get the tubo in. Once I am runnind at a decent speed there is no problem. But from standing there is nothing. There is a slight hill at the end of my street and I cannot go faster than 20mph at first. (My wifes little hyundai Getz will beat me every time). Any suggestions as to what the problem may be