What is a Delivery Valve?
When it comes to the fuel side of things, there are 3 aspects of the P-Pumped trucks that determine how much power can be produced; the injection pump itself, the fuel injectors, and the delivery valves. In the P7100 pump, the delivery valves are essentially “check-valves” installed between the pump and the injector, controlling the overall amount of fuel that goes into the injector before it is sprayed into the piston bowl. Consequently, a larger delivery valve allows a longer duration of the injection event, thereby increasing potential power. There is a tradeoff, however, as a larger delivery valve increases duration it results in a longer, less efficient injection event. While the increase in flow does produce more power, it does so at the expense of heat and smoke. A smaller delivery valve paired with the same injector will have a shorter injection event, this results in a clean and concise burn, which will make less power but will ultimately drop EGT’s and be more efficient. As a final note, stock/small delivery valves become restrictions around 3000rpm where a larger delivery valve will maintain peak flow throughout the rpm range. This is a must for those seeking high-rpm power.
Big DV’s/Small Injector’s vs. Small DV’s/Big Injectors
Both delivery valves and injectors are used to increase power output via increasing total fuel flow. A small Delivery Valve/Large Injector combination for a given power level will produce clean and efficient power. A Large Delivery Valve/Small Injector combination can produce the same power as the small DV/large injector combo but with more heat and smoke. It seems like a no-brainer, so why do so many choose to go with the later? The answer is in the cost. Delivery valves are much cheaper than injectors, for those looking to stay within a given budget the larger injectors may not fit the bill. Some of our customers choose to keep the stock delivery valves and only upgrade to larger injectors in order to create the most efficient power. However, a large advantage of any delivery valve upgrade is the significant increase in throttle response that is often not attainable by injectors alone.