Theo Decker was one of the best known Beetle tuners of his time – he started breathing on air-cooled engines back in 1958 and his period engine tweaking still holds a huge amount of kudos on the vintage speed scene today.
Typical modifications to come out of his Theo Decker Essen (TDE) workshops included his twin carb conversion kits, hotter camshafts, reworked cylinder heads and optimised pistons. He always did the machine work himself. Some of his most popular tuning accessory included his bypass oil filter, as well tailpipes which looked stock but had a larger internal bore for a deeper resonance and a few more horsepower. Apparently, over 500 of these were sold every month.
As early as 1965 he was reboring the original 1192cc engine to 1285cc, thus increasing power from 34 to 40bhp, years ahead of VW itself launching its 1300 Beetle. He also authored books about making Beetles (and later Golfs) go faster and was a key player in the Formula Vee circles.
Decker also got involved with Volkswagen’s special edition SP1600 made for the South African market in 1975. It featured twin Solex H32/24PDS1/2 carbs on a 1600cc engine, which produced 58bhp. One of his last hoorahs was entering a TDE tuned 135bhp 1302 Beetle into the Classic Car Challenge China, driven by F1 ace Jacky Ickx.
Courtesy VW Heritage.