E85 vs 91 for street

Are new flex fuel motors really over 10 to 1 compression? How do they do that when running regular gas?
Oh yeah. Over 10:1 is really common. The 2016 3.6 pentastar is 11.5:1 which is decent for port injection. A couple small direct injected 4cyl are over 12:1. Running an Atkinson cycle, direct injection and/or cooled egr help them run knock free on 87oct.

Toyota is coming out with variable compression gas 4cly. It varies cr from 9:1 with high boost port+direct injection and 14:1 at low loads with direct injection