I'm just looking for some insight on the amount of compression ratio in a cylinder and what lowering it for FI does in terms of PSI. If stock compression is 10.3:1 for a 2003 engine - what would it have for a compression test rating in PSI? As we drop the compression ratio in a built motor for FI down to 8.8:1 - what is the expected PSI in this range for a healthy newly built engine. In between these ratios is there a consistent drop in PSI per engine? Thank you, appreciated.

 

Anyone?