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Thoughts about engine choice
I’m thankful to all who have made suggestions about potential engine alternatives. One key aspect of this project is the proprietary nature of the engine, in fact it should be possible to fit many different types within the frame design. However the essential feature of my design is the “under the seat” location, which excludes all vertical piston engines. Unfortunately there are too few motors with “horizontal” architecture, particularly diesel versions. Hopefully this will change in the future, as manufacturers around the world align their products with the new realities of efficiency being more important than brute power.
Thoughts about cooling
Thanks to beatr911 for his information on cooling ducts, particularly the ratio of area to hp. I haven’t seen published figures for this before and its good to get a confirmation that my guesswork is “in the ballpark”. At its narrowest point the intake duct is 30mm x 265mm, which equates to 12.3sq inches. Racecar ducted cooling systems are often described as “push and pull” systems, referring to the use of pressure differentials. I feel that the “pull” element, extracting into a low pressure zone is the more important of the two forces. Therefore I am making my exit vent size about twice the size of the inlet.
Some time ago I saw a Honda C90 for sale on e-bay with a 100cc liquid cooled engine conversion but I have not been able to find more info about this. Obviously I would prefer to run a liquid cooled motor at some point, and if the project falls short of its target, then a Honda Wave/Innova 125 is a prime candidate.
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