December 2, 2023


We Bring Good Things to Life

DIY Genius Grafts Koenigsegg-Style Freevalve Tech Onto 6.5-HP Harbor Freight Motor

Building a 1960s Formula 1-inspired car from scratch is something one does not only for the fun of it, but also to save some money on a top-level vintage racing experience. So when Wesley Kagan learned custom camshafts for his Porsche Boxster-based open-wheeler could cost thousands of dollars, he turned again to his own DIY skills for a solution. Not one that involves grinding his own cam lobes, but one that involves replicating Koenigsegg’s “Freevalve” pneumatic cylinder head technology on a 6.5-horsepower, 212cc Harbor Freight Predator engine.

Copying the proprietary tech of one of the world’s foremost hypercar manufacturers proved more straightforward than it initially sounds, though it wasn’t something Kagan could’ve done without his knowledge of engineering, electronics, and programming. After taking measurements of the Predator’s cylinder head, he used CAD to design a pneumatic valve train to fit it, one that’d operate using a 130-hertz pneumatic actuator and an eight-bit controller he assembled and programmed himself. After manufacturing all the necessary mechanical components, Kagan assembled his creation, and after some further fiddling, fired it to life.

Kagan’s pneumatically valved Predator ran, but because of issues he suspected lay with his coding, it refused to accelerate. To expedite his reprogramming, Kagan shared his code online so others can suggest fixes to his code, or ways of streamlining it. He also shared the CAD files for his creation so others can put together their own Koenigsegg-Harbor Freight Frankensteins, which will no doubt result in some interesting expulsions from kart races.