My percentage in B.E is 52. I am trying to apply MBA in LIU brooklyn campus. How much I should score in GMAT and IELTS?

Have you considered reading their website? http://liu.edu/post/com/~/~/link.aspx?_id=80786D9EE4FD41908C0FB008421F06B5&_z=z

You'd need to convert your undergrad percentage to a GPA on a 4-point scale. They require a 400 GMAT score but they'll want something higher if your GPA is low.