Do we know how VIT allocates the ranks? Is this based on the marks scored in the exam alone or any other logic?

Equipercentile equating method is used as statistical techniques which uses algorithm to derive ranks.
This logic hasbeen usedby VIT authorities for rank calculation for meaningful and fair comparison.

For more detaiks you can refer exam results section in the following link to better understanding of the score calculations methodology.

http://www.vit.ac.in/btechadmissions/viteee2018

All the best for admission counselling.

Just on viteee score and nothing