Best temperature to cook 6.6lb turkey that I want to be finished in one and half hours

I would suggest 350 to 375° F which should get it done in about 1 1/2 hours but definitely check earlier just in case for internal temp of 165° F. This article has more information: https://food52.com/blog/11646-the-essential-numbers-a-guide-to-times-and-temps-for-cooking-your-bird

Hi there, Here are our tips on temps and times for cooking turkey: http://food52.com/blog/11646-the-essential-numbers-a-guide-to-times-and-temps-for-cooking-your-bird