OK..I have noticed a few members ask what the correct compression in PSI is for the 1.2L Spark engine is. With the compression ratio at 10.5:1 the correct compression is 152-PSI at sea level and about 148-PSI at elevation of 1,000ft ASL. Average is 150PSI at 500ft ASL. Of course ambient temp and elevation play a fairly small part in the PSI #. As you can see the difference between sea level and 1,000ft does not produce much of a difference..the ambient temp variation is even less. Surprising as it may seem, all engines of all types have the exact same PSI at the same compression ratio. For exa