Porsche Special Tools P 228 b and P228 c Throttle Correlation Protractors
On cars with mechanical fuel injection, there is a requirement that the movement of the regulator control arm on the injection pump moves in correlation with the opening of the throttle body valves. This correlation is determined by the length of the link rods connecting the throttle bodies to the cross shaft. By shortening or lengthening the links the amount of movement at the throttle body can be adjusted. Once set up the volume of fuel delivered by the pump is then directly correlated to the volume of air being drawn through the induction stacks. It is essential that all the throttles come off their stops at the same time and that the opening angle of the throttles on the left bank are matched with those of the right and with the pump.
To determine this Porsche designed a set of protractors to be fitted to the pump and throttle bodies during tuning. These Protractors were sold to Porsche dealers, and were available as a spare part service tool to owners and independent garages.
Now after years of being unobtainable, I have had the Porsche Special Tools P228B and P228C remanufactured. These protractors are an exact replica of the original Porsche Special Tools except they are be fitted with much stronger Neodymium magnets in place of the original Ferrite magnets. The degree scales have been accurately calibrated to each protractor individually in 1-degree intervals as the originals and accurately printed Black on Silver foil vinyl.
The set contains all five protractors, a set of five brass pointers, preformed to fit and requiring only minimal adjustment to zero during use. The protractors are supplied in a plastic storage case with fitted foam insert and come with Fitting and Operating Instructions including calibration data.