BMW CP4.2 Pump Modified “Stroker” Shaft (OEM-Based)
The modified CP4.2 pump shaft (“stroker shaft”) is manufactured using an OEM core and is designed to significantly increase the performance of the CP4 pump.
When installed, the pump can supply enough fuel for systems requiring up to 700 hp.
Compatible with BMW diesel engines N57 and B57 equipped with a CP4.2 pump.
A stroker-type shaft increases the pump’s stroke length, allowing it to deliver more fuel per revolution while preserving the factory pump construction and control logic. This prevents fuel starvation under high load and ensures stable engine performance in high-power applications.
Compatibility
Fits BMW diesel engines N57 and B57 with the CP4.2 pump
Intended for engines where the stock pump cannot meet fuel demand
Fits only CP4 pumps with a smooth housing (as shown on the right side of the reference image)
Not compatible with pumps featuring housing protrusions (as shown on the left side)
Installation
Recommended for professional installation by specialists experienced with high-pressure fuel systems
Can be installed by experienced DIY users with proper tools and the ability to work in extremely clean conditions
(any contamination may cause pump damage or reduce its lifespan)
Recommendation
The modified shaft increases pump output but does not protect against common CP4 pump failure modes.
For this reason, we strongly recommend installing a CP4 Fuel System Protection Kit (Disaster Prevention Kit) to protect the fuel rail and injectors in the event of pump failure.
Included in the package
Modified CP4.2 pump shaft (pump not included)
Installation manual
