I was reading a book a guy at work brought in called, "supercharging, turbocharging, and nitrous oxide performance handbook" Author's were Earl and Diane Davis.

They have a chart on page 42 that shows final compression ratio at boost. One side is beginning CR, across the top is 2# incremental boost. I followed it across at 8.5 cr all the way to 12# and it equates to a 15.4 cr!! I had no idea we could push that kind of pressure!! That's compression ignition range.

FYI,
Bryan

 

That's why we have to keep the A/F down around 11.8, to prevent compression ignition aka "detonation".

 

and people wonder if the plugs stay in why the head gasket blows?

What about those of us running a little more boost than that? Like 16-17# of boost?

Suavy's 26# of boost?

 

16=17.8
18=18.9
20=19.8
22=20.9
24=21.9

SUAVY=