The College of Engineering admits by major. They provide the ranges and averages for gpa & SAT although the latest data is a year old (assume it has gotten harder). For example the bottom 25th percentile math SAT for the CS kids that just graduated in 2018 is 90 points lower than the frosh admitted last year!
You can find the info for engineering at http://bap.ucsb.edu/institutional.research/planning.data.book/tables/academic.unit.engr.pdf
For CS the info is at
http://bap.ucsb.edu/institutional.research/planning.data.book/tables/academic.unit.coms.pdf
Your suspicions are right, the averages are higher than for Letters and Science. And as pointed out by @Gumbymom admission is not done just by stats, they look at other factors.