Atmospheric pressure

Thanks for the information they share ... how valuable it is to be in contact with people who know wsobre this complex matter ....

The amount of air is not always the same in a natural aspiration engine, the volumetric yield varies according to the Motor RPM to the highest velovity of the engine, the volumetric plaster is less and if the performance lowers the compression also, so that the compression is measured in starter speed and I believe that if the manuals do not bring as condition the atmospheric pressure to measure the compression is because it is negligible.

1 atm = 1 bar = 14.5 psi.