ok the setup was 2 1/2 all the way back to a n1turbo muffler. I had the n1 at an angle and there were some bad kinks were the muffler was angled the car was tuned like that . Today i had mandrel bends put in and the small n1 put on .my question is it feels like the car lost some power/tq. the car is fully built n/a could the mandrel bends hurt me?

 

Too little back pressure on a n/a car would cause torque loss. This would be obvious if you went from a 2.5" to a 3". But I would not think it would be that much of a noticable difference by just going to a mandrel bend.
So I guess I'm no help to you at all........

 

well, ID gets smaller; sometimes up to 40% i believe.
And hurts velocity

 

smaller?