In response to some questions from me, Evan Belworthy of New Zealand has this to share after 30 years of experience with the VW installation in his FRED ZK-FRD:

“Fred has a 1835 cc VW running a Johnson Outboard carburetor and single battery ignition.  The original had a magneto also, driven off the crankshaft, but the single ignition is fine.  The carb heat box is a light switch box and the heat is off an exhaust muff, we run a mix of warm air all of the time and hot air for the carb heat.  The engine still has the original mechanical fuel pump.

“Idle 750 rpm, full power static gives 2800, takeoff and climb 2900 and straight and level 3100 full throttle.  In cruise at 2800 gives us 65 knots indicated using between 15 and 18 litres [4-4.45 U.S. gallons] per hour.

“These figures are what I used on Tuesday, as I had to pull Fred out and go for a fly….

“Fred has a Hegy 60 X 30 propeller, I have tried 62 and 60 x 32, the prop dates back to 1977 ex a VP1.  Also under the engine is a standard VW oil cooler that we have mounted externally, with 1600 no oil cooler was required but it is required on the 1835.”

Photo:  ZK-FRD shows off its simple but effective VW conversion.  Courtesy of Evan Belworthy.