The performance of unbalanced regulators changes as the cylinder pressure falls, usually becoming slightly harder breathing.

There is, however, no formula to calculate compression ratio based on cylinder pressure.

Additionally, the cylinder pressure developed when an engine is running will be higher than that shown in a compression test for several reasons.

A local shockwave is created around each pocket and the cylinder pressure may rise sharply beyond its design limits.

When the cylinder pressure was running low and air demand effort rising, a roll to the right side made breathing easier.

This leads to a rapid rise in cylinder pressure, producing engine "knock".

The main function of cylinder body is to hold cylinder pressure.

Engineers can tune an engine to have the air intake valve close earlier, which helps cylinder pressure build.

Other data such as water temperature and cylinder pressure are also sometimes displayed.

More advanced dive computers also include additional information into the calculations, for example, the water temperature or the diving cylinder pressure.