The IMEI blocking process is controversial, your device can be blocked any time after 2 days, but this can take up to 2 weeks.
Here is a detailed information of Turkish sim cards, and some workaround for those who dont want to hassle with paperwork, registration etc. Renting a 3g hotspot device seems the best option for Turkey.
I hope this can help you
http://prepaidwithdata.wikia.com/wiki/Turkey