Porting Calculator V4.2.2 Jun 2026

A ratio comparing the actual measured flow against the theoretical maximum flow of a perfect orifice. Indicates the aerodynamic efficiency of the port shape.

The software assists in calculating the correct venturi diameters below the valve seat. By determining the exact throat percentage (typically 85% to 90% of the valve diameter depending on the application), the tool ensures a smooth transition from the port runner to the valve chamber. Version 4.2.2 Specific Enhancements

: Includes updated thermal expansion variables for modern aluminum alloys and compact graphite iron (CGI) cylinder heads, allowing for highly precise volume-to-weight conversions.

To truly master , follow these pro tips: Porting Calculator V4.2.2

Factors in localized barometric pressure, temperature, and humidity for hyper-accurate flow bench correlations. Core Calculations Performed by the Software

Whether you are tuning a vintage two-stroke for competitive racing or simply seeking to optimize engine efficiency, Porting Calculator V4.2.2 offers the computational power and visualization tools necessary to transform theoretical modifications into measurable performance gains. When combined with careful physical measurement and real-world testing, this software becomes an indispensable asset in any two-stroke tuner’s toolkit.

Looking to understand how changes in port timing affect an engine. A ratio comparing the actual measured flow against

: Enables quicker and smoother number porting, leading to higher customer satisfaction.

The software allows main transfer ports to be locked to a blowdown time value relative to the exhaust port. Auxiliary and boost ports can be offset from the main transfer timing by a user‑defined number of degrees. This ensures a harmonised port timing strategy.

You enter the desired duration. The program uses that duration together with stock cylinder specifications and barrel height setting to calculate the required change in port height. In this mode, upward barrel adjustment is limited to keep the “raise port” values positive. By determining the exact throat percentage (typically 85%

While based on the established V4.2.1 framework, version 4.2.2 focuses on refining the user interface and calculation accuracy: Visual Feedback

The you are working on (e.g., 50cc scooter, 250cc dirt bike).

To help tailor this guide further, let me know: What (2-stroke or 4-stroke) are you working on? What is your target RPM range , and do you plan to do the grinding manually or via CNC ? Share public link

: The software calculates the ideal cross-sectional area of both intake and exhaust ports. It helps users determine the minimum cross-sectional area (often at the port pinch or short turn apex) needed to support a specific target horsepower without causing flow separation.