Bosch PESK6KL 70/120 R11
Fuel Injection Pump
A MOVE TOWARD MODERNITY
The PES6KL 70/120 R11 marked a big step forward in fuel injection pump design and operation featuring 6 plungers (one for each injector), the complete removal of the separate corrector assembly, a start solenoid, and a 3D space cam for more accurate fuel mapping.
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Six plungers allow for greater fuel efficiency, more control over each plunger and corresponding injector operation, and a greater ability to adjust the operation of the fuel injection pump for various environments, temperatures, and working conditions. Though advancements continued to be made, most fuel injection pumps would follow the R11 in general layout until continuous fuel injection (Bosch CIS) took over in the mid 70s.
The R11 can be found in earlier W113 models such as the 230SL but was replaced fairly quickly in the following years with the R18's and eventually the R20's.
Major differences include a smaller viewing port, operational inlets and outlets on the rear-side, a starting solenoid (stopping solenoid would be added in later models), and the lack of ribs on the backside which would be added later to save on weight. You can also see remnants from the pneumatic governor pumps such as the large triangular shape on the lower front right where the fuel feed pump would have attached on pumps like the R9/22 and R8.
