### Dynamic, Static Comp Ratio & Cranking Pressure Calculator

Posted:

**January 14th, 2011, 5:12 pm**This Excel file will calculate Dynamic and Static Compression Ratios for 5 different engines and show you the

results side-by-side. If you don't have the "Intake Valve Closing Angle", there is also a calculator for that.

I prefer this to online calculators. I can save my results and review them later, can't do that with the online

versions. You can only look at one calculation at a time when online, not so with this Excel spreadsheet...you

can see all 5 versions at the same time !!!

You will need Microsoft Excel 2007 or you can download "Open Office" for FREE here http://www.openoffice.org/.

Open Office can open and work with Excel spreadsheets. If you have an earlier version of Excel, then you can install the

Microsoft Office Compatibility PackĀ, it's also FREE from Microsoft.

Use this link for information on how to install Office Compatibility Pack:

http://support.microsoft.com/kb/923505

02/09/2011 (Version 02) - Edited Excel file to correct some text. Nothing changed that would effect a calculated value.

Previous Downloads = 5

01/17/2014 (Version 3) - Edited the Excel file to include the "Cranking Pressure", you will have to add the atmospheric pressure. This goes hand-in-hand with the DCR, since the lower the atmospheric pressure the lower the cranking pressure. Something to consider if you live at higher altitudes. With less atmospheric pressure you will be able to use a higher DCR. For the cranking pressure calculation, I used an Adiabatic Constant of 1.2, this seemed to be the best approximation for the real world. That number is based on the link below .....

http://victorylibrary.com/mopar/cam-tech-c.htm

Nothing changed that will effect the previous calculated values.

Also added some text and changed some colors. The different colors will help make the text clearer with the better contrast when posted in a topic. I only updated the first graphic below.

Previous total downloads = 154

Download the Excel file below:

results side-by-side. If you don't have the "Intake Valve Closing Angle", there is also a calculator for that.

I prefer this to online calculators. I can save my results and review them later, can't do that with the online

versions. You can only look at one calculation at a time when online, not so with this Excel spreadsheet...you

can see all 5 versions at the same time !!!

You will need Microsoft Excel 2007 or you can download "Open Office" for FREE here http://www.openoffice.org/.

Open Office can open and work with Excel spreadsheets. If you have an earlier version of Excel, then you can install the

Microsoft Office Compatibility PackĀ, it's also FREE from Microsoft.

Use this link for information on how to install Office Compatibility Pack:

http://support.microsoft.com/kb/923505

02/09/2011 (Version 02) - Edited Excel file to correct some text. Nothing changed that would effect a calculated value.

Previous Downloads = 5

01/17/2014 (Version 3) - Edited the Excel file to include the "Cranking Pressure", you will have to add the atmospheric pressure. This goes hand-in-hand with the DCR, since the lower the atmospheric pressure the lower the cranking pressure. Something to consider if you live at higher altitudes. With less atmospheric pressure you will be able to use a higher DCR. For the cranking pressure calculation, I used an Adiabatic Constant of 1.2, this seemed to be the best approximation for the real world. That number is based on the link below .....

http://victorylibrary.com/mopar/cam-tech-c.htm

Nothing changed that will effect the previous calculated values.

Also added some text and changed some colors. The different colors will help make the text clearer with the better contrast when posted in a topic. I only updated the first graphic below.

Previous total downloads = 154

Download the Excel file below: