Administrator, Resident Tater Salad
On par with most modern non-DI N/A engines.The 1.8 has a compression ratio of 10.5:1. Saw the spec sheet for myself when my brother bought his 2012 ls. Fortunately I was there to ask that question as the salesman pointed at the 138 hp spec on the info board. He ended up taking me to a back office computer and brought up the full spec sheet for me to see.
I could see it helping with a heat soaked engine or low RPM power. Our Toyota has the same CR and runs slightly better on 89 than 87 on a hot summer day with the A/C cranked. 93 makes zero difference in that.