Your seat depends upon the cutoff rather than marks. Cutoff changes pretty much every year for all courses although a general trend can be seen. The cutoff depends upon a number of factors like the total number of students taking the exam, the total number of students qualifying the exam and the number of seats in a course. 

In VIT Vellore, the closing rank for Automotive Engineering was was around 17000 in 2018. So, to be on the safe side aim for a rank of below 15000. Good luck. 

Hi dear,

You have to secure a rank under 12k for automobile engineering in vit vallore.for  that you have to score between 45 to 60.final cutoff marks may vary this year.you can check cutoff rank of all branches here

https://engineering.careers360.com/articles/viteee-cutoff/amp

Hope it helps