The 15-19 pump interchanges with earlier 2011-2014 MY vehicles and displaces 15% more than the stock pump. Great for your hot tuned 11-14 truck to ensure proper rail pressure.

Three variations:
11-23 applications with the updated 15-19 pump output. (7.5mm)
10% over for hot tuned trucks (8.25mm)
And the infamous 10.3mm 38% over pump.

This CPX keeps the OEM, four pumps per engine revolution that the Chinese eccentric pumps do not. The OEM Bosch system is timed, and designed to pump to the bank that is requesting fuel (firing). This is to ensure peak nozzle pressure and less harmonics of high pressure fuel, having to cross over via the balance tube, from one rail to the other. Eccentric pumps will skip every other firing event. Two pumps per revolution vs the OEM four..
And just to point out, the whole “US diesel fuel doesn’t have enough lubricity for the CP4.” That’s a lie. I have disassembled, measured and under microscope, inspected pumps with over 500k miles with essentially zero wear.

The flaw was nothing to stop the roller lifter from rotating in a vacuum event. (Gel, filter change, low pressure feed issue.) This is why the LML Duramax pumps drop like flies. There is no lift pump to keep positive pressure on the plungers and barrels.
This allows a slop, or gap between the cam and the lifter roller. Which allows it to turn. Similar to a roller cam in a engine. When there is no lifter guide or link bar. The lifter rotates, destroying the cam and lifters and filling the engine with hardened metal filings. These filings, are what fills your fuel rails and injectors with debris, ruining them.