To simplify the expression (2y^2 / y - 8) - 2y, we first need to factor out the common term in the numerator of the fraction:

2y^2 / y - 8 = 2y * y / y - 8 = 2y - 8

Now, substituting this into the original expression:

( 2y - 8 ) - 2y = 2y - 2y - 8 = -8

Therefore, the simplified expression is -8.