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5-hole vs. 6-hole vs. 7 hole Injectors

Like countless others, you may be wondering what the difference is between all of the injector sizes/hole counts and surfing the internet to find the answer can often lead to more confusion. We’re here to shed some light on the matter. Per a given flow amount, an injector with a smaller hole count and larger orifice size will penetrate deeper into the piston bowl. Depending on the rpm for the application, this could be an advantage or a drawback. An injector of the same flow with a larger hole count and smaller orifice size will produce a finer spray and penetrate less deeply into the bowl, meaning that it will burn sooner at lower rpm/boost levels. The real world effects of this seem to come in the form of burn efficiency at a given rpm. At low rpm, the 7-hole better disperses fuel into the air charge which results in increased burn efficiency (more power). There is a cross-over point around 2000rpm where the deeper penetration of the 5-hole injector results in better fuel dispersion into the increasingly turbulent air charge, enabling a more complete burn which results in more power. While apparent, these differences are minimal until 3000rpm. The 5-hole style injector is by far the most common and is the best choice for most applications.

Cummins Injectors, SAC vs VCO Nozzles | Power Driven Diesel

Double The Horsepower of Your 12 Valve Cummins | Power Driven Diesel