MecaTest Mobile Application,
Pressure Calculation Tutorial

Due to sensor limitations, the calculation of cylinder pressures is limited to 3 and 4 cylinder engines.

The pressure values displayed in MECATEST are an approximation and cannot replace values measured with a compressiometer.

Step 1 : Engine Technical Data Needed

To calculate the pressure values, MecaTest needs engine technical data. Click on the “engine” symbol to open the input form.

Due to sensor limitations, the calculation of cylinder pressures is limited to 3 and 4 cylinder engines.

Step 2 : Values and Units

Before entering data, select the Metric or Imperial unit system.
If you choose
– “Metric”, the pressures will be expressed in Bar, the displacement in Cm3
– “Imperial”, the pressures will be expressed in Psi, the displacement in In3
The engine displacement is calculated based on the stroke and bore values entered.

The various data  (compression ratio, bore, stroke)  are most often available on the Internet

Step 3 : No load battery voltage Value

Disconnect the negative terminal and measure the battery’s no-load voltage with a multimeter. Note the value to the nearest tenth of a volt.

Currently MecaTest only takes into account a single battery and not two batteries connected in parallel or in series.

 

Step 4 : Max current Value

Locate the data label on the battery and note the maximum current value, often noted with the expression CCA.

Step 5 : Perform the test as usual

– Place the iPhone close to the negative terminal of the battery, no matter the orientation of the iPhone.

– Press the “Record” button take the speaker with you and go to the driver’s seat. (15-seconds countdown)

– Be prepare to listen to the instruction….

Step 6 : Affichage de la pression en Bar

If you choose the “Metric” unit system, the pressures will be displayed in Bar.
If an engine data value is not entered, the pressures are not calculated and only the relative compression test percentages will be displayed.

Step 7 : Follow the instructions, be prepared to crank

If you choose the “Imperial” unit system, the pressures will be displayed in Psi.
If an engine data value is not entered, the pressures are not calculated and only the relative compression test percentages will be displayed.