Yes, Many !!
BITSAT is bit easier than IIT JEE exam. Also screwing up JEE gives you chance to self evaluation and motivates to crack BITSAT 😛
My sidy in 2nd year, did not cleared IIT JEE but got computer science in Pilani campus.
So dont compare IIT JEE & BITSAT. Both offer different type of exams and depth & number of questions are also different. For BITSAT start with previous paper if any & mock exams.
All the best !!