I have a dodge i-4 turbo. @ 18lbs i am between 11.4-11.8 respectively. From the factory @ 12psi it was at 10.1-11.1 depending on how the pcm decided to compensate that day. If i go above 12.3 I get the knock sensor kicking in, and anything below 10.5 I end up losing considerable power.

 

thanks that makes sense.