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Deze reply is gepost in de afdeling Technical Forum in het onderwerp 'Foekema Symatric Two-stroke system' (ID 47394).
De reply is geschreven door LucF (UserID 3480) op 31-1-2008 14:25.

Dean from Los Angeles did use the "Holey Wonder" in 1968

Dus toch, of toch net niet geheel, maar nu is dan een eerdere uitvinder die het bijna op dezelfde manier deed. Wel niet perfect, maar wel op hetzelfde principe, met uitlaten boven de spoelpoorten. Hij gebruikte een bestaande cilinder en daarin zit natuurlijk wel een uitlaat die tot het o.d.p. open staat. Het systeem was dus niet 100% symetrisch. De manier waarop hij het deed is wel heel opmerkelijk, dat er zoveel vermogen uitkwam.

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I had that same sort of thought in 1968 when I was racing karts. I realized there was no where near enough exhaust area on the McCulloch kart engines. So I drilled 18 exhaust holes above the intakes. Vented to the atmosphere. After some experimentation I discovered that at low speeds the intake charge went directly out the exhaust, so there was no such thing as low end torque. Since is was ported directly outside, at low speeds, like at starting, it blew fuel out of everywhere and gave the distinct sound and visual impression of a blown head gasket.

Once it came up on the pipe, it produced glorious amounts of power. It was named the Holey Wonder, not only for the holes, but for the unworldy sound it made at full pop. The conventional ported McCulloch would wind up to 12-13,000 rpm. This thing made 18,000 rpm. Won quite a few races with it.

The rod wasn't up to the task I soon found out. It would last about 3 short races and break. Always at the top end of the rod. And then it would transform itself into an 18,000 rpm buzz saw. I still have scars from one of the grenade jobs.

Piston ring life on an extreme ported engine is not long, but you live with the trade offs.

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