Center the ball

[BrendAn]

Today I was playing with the position of the ball when flying straight.

I always need left rudder to keep the ball centred. Which I guess is normal. Now if I take my feet off the pedals the ball sits a about halfway over the line on the left. I took notice of the speed and it does not change. I thought I would lose some speed if it was yawing . And the other question is how are turn coordinators setup in relation to the aircraft or doesn't it matter.