Performance Trends, Inc.

Producing Quality Computer Tools for Racers and Engine Builders since 1986

Compression Ratio Calculator v2.3 for Windows XP/Vista/Win 7/Win 8/Win 10/Win 11

Computer Program to Calculate Compression Ratio, Boring, Stroking and Other Common Engine Building Dimensions.


Compression Ratio Calculator is probably the most detailed compression ratio calculator program available. It includes these features:

  • Calculating compression ratio, Cylinder Volume, and engine displacement from a variety of different inputs.
  • Finding which input value (chamber CCs, Deck Ht Clearance, etc) will produce a desired C.R. 
  • Determining the % contribution of various dimensions on the overall compression ratio.
  • Calculating Bore/Stroke and Rod/Stroke Ratios.
  • Calculating boring and/or stroking effects.
  • Determining required bore or stroke for a desired displacement.
  • Calculating cranking compression pressure and dynamic compression ratio.
  • Saving and printing specs.
  • Using English or Metric units.
  • Determining Piston Dome or dish volume.
  • Enter Head Gasket volume as Bore and Thickness, or Volume CCs directly.
  • Determining any of the following: rod length, deck height, deck height clearance, piston compression height, or stroke based on you specifying the other 4.

for an example of Compression Ratio Calculator printout (including some Plus Version options).

 

Compression Ratio Calculator PLUS adds even more feature to make this already complete Engine Builder program.  These include:

  • Calculating Effective Compression Ratio (used by supercharger companies to show requirements for boosted engines).
  • Calculating Piston Speed, Gs, and estimating Rod Bolt Loads for a particular RPM.
  • Adding more input details to better estimate Cranking Compression pressure.
  • Being able to pick Gasket Bore Diameter and Gasket Thickness from known FelPro gaskets.
  • Being able to calculate the effect on "Chamber CCs in Head" by milling the Head.

Plus Version's screen, with blue arrows and blue border highlighting some of the additional features.  It also shows the "Pick a Felpro Head Gasket" feature (light blue frame) by clicking on the "Clc" button for Gasket Bore or Gasket Thickness.

 

New Plus Version Options

 

 

Compression Ratio Calculator PRO adds several more feature to make this the "go to" software for professional Engine Builders.  These include:

  • Being able to calculate Piston Dome CCs based on geometry, from either a tapered dome or hemispherical dome.
  • Being able to calculate Piston Dish CCs based on geometry, from either a tapered dome or hemispherical dome, or a radiused flat bottom dish.
  • Being able to calculate Valve Relief CCs based on geometry.
  • Being able to calculate the change in Combustion Chamber CCs by sinking the valves into the head more, or having them protrude more into the chamber.
  • It has an Option setting which allows it to work better with international Regional Settings which use a comma "," for the decimal point instead of the point or period "." 
  • The Company Logo graphic image will appear on the screen, in addition to printouts.
  • There is an option to determine either the Bore or Stroke to produce a desired engine displacement.
  • If you use the option of entering Head Gasket Volume directly, you can also choose to enter Gasket Thickness.  This can be handy for flathead engines where the gasket area is much larger than the bore area.  Then if you change Gasket Thickness the program asks if you want the Gasket Volume changed appropriately.
  • You can create tables of various outputs from a range of inputs that you can specify:
        Engine Displacement vs Bore
        Engine Displacement vs Stroke
        Cranking Compression vs Cranking RPM
        Cylinder Volume vs Degrees of Piston Movement from TDC
        Bolt Loads vs RPM
        Dynamic Compression Ratio vs Intake Valve Closing

 

PRO Version's Calculated Piston Dome CCs from Geometry
 (click image to enlarge)

 

PRO Version's Calculated Valve Relief CCs from Geometry
Compression-Ratio-Valve-Relief.gif (37259 bytes) (click image to enlarge)

 

PRO Version's Calculated Valve Relief CCs (4 Valve) from Geometry
Compression-Ratio-Valve-Relief-4-Valve.gif (17719 bytes) (click image to enlarge)

 

PRO Version's Calculated Piston Dish from Geometry (tapered dish)
Compression-Ratio-Piston-Dish.gif (12952 bytes) (click image to enlarge)

 

PRO Version's Calculated Piston Dish from Geometry (radiused flat bottom dish)
Compression-Ratio-Dish-Volume-Calculator.gif (13842 bytes) (click image to enlarge)

 

PRO Version's Calculated Valve Depth Change Effect on Chamber Volume
Compression-Ratio-Valve-Protrusion-Chamber-CCs.gif (11236 bytes) (click image to enlarge)

 

PRO Version's Table of Bolt Loads vs RPM  (many other types of Tables and ranges of inputs available)

 

 

What You Need:

Computer with Windows XP, Vista, Windows 7, Windows 8, Windows 10, Windows 11

 

More Information, Download Demo:

to go to our Demo Downloading page to download a FREE Compression Ratio Calculator Demo

More Information, Watch Demo Movies:

to go to our Demo Movie page to watch Compression Ratio Calculator Demo Movies .

 

To Order:

 Compression Ratio Calc.: Our DOWNLOAD ONLY option. If you only want the unlocking code and DO NOT want a CD shipped, click on Add to Cart below. You will not be charged shipping.

$49.95

Compression Ratio Calc. Standard: If you want a CD shipped to you, click on Add to Cart below. There will be shipping charges added to your order. You can still download the demo and get your unlock code sooner with this option.
$49.95 plus shipping

Compression Ratio Calc. Plus: Our DOWNLOAD ONLY option. If you only want the unlocking code and DO NOT want a CD shipped, click on Add to Cart below. You will not be charged shipping.
$69.95

Compression Ratio Calc. Plus: If you want a CD shipped to you, click on Add to Cart below. There will be shipping charges added to your order. You can still download the demo and get your unlock code sooner with this option.
$69.95 plus shipping

Compression Ratio Calc. Pro: Our DOWNLOAD ONLY option. If you only want the unlocking code and DO NOT want a CD shipped, click on Add to Cart below. You will not be charged shipping.
$99.95

Compression Ratio Calc. Pro: If you want a CD shipped to you, click on Add to Cart below. There will be shipping charges added to your order. You can still download the demo and get your unlock code sooner with this option.
$99.95 plus shipping

You can download this program as a demo Free to try it. If you want to order it, call 248-473-9230 with your Visa, MC, AmExp or Discover card. Performance Trends can provide you an "unlocking code" number to activate all features (bring it out of demo mode). When newer versions are released, you can download the latest demo and activate all features with this same "unlocking code".

The "on screen" help explains all features, inputs and outputs. This program does not come with a user’s manual.

for Performance Trends Full Price List and ordering info.

 

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