Single vs. Dual Fuel Injection

Depending upon your particular set of rules, you may be able to choose between single or dual fuel injection systems. Single injection systems offer one injector near the intake valve. Most stock systems are single injection. Dual Injection offers one injector near the intake valve and one injector above the intake stack very far from the intake valve. Dual injection systems may be offered as an upgrade to older model engines or they may come stock on the newer generation of engines.

In a dual injection system, when the injector above intake stack is activated, the fuel travels much further and has more time to vaporize and take more heat out of the air. This generates increased mid-range performance. The lower injector is used for low rpm cruise and supplies additional fuel during quick throttle movements for best throttle response.

Adding dual injection to a single injection system always increases power in the mid-range. This increase in mid-range power can be valuable in two ways. First, the system can be left as-is to allow maximum benefit exiting the turn. Secondly, the engine can also be mechanically tuned for more top-end performance which would normally decrease the mid-range power, but since the dual injection adds mid-range power, there is no loss in mid-range power.