Fuel Injectors¶
The injector hardware: flow rate, mounting position, dead time, and impedance. Size them to power without wrecking idle resolution.
What it is¶
This is where you choose the injector hardware for the build (the Fuel page injectors topic covers how the ECU uses them). The properties:
- Flow rate (cc/min) — peak fuel capacity, setting the power ceiling.
- Position — port, direct, or throttle-body injection.
- Dead time — the open/close latency, which the ECU compensates for.
- Impedance — the electrical type of the injector.
Why it matters¶
Injector sizing is the same trade described in Injectors, made concrete at build time:
- Too small → the injector maxes out (100% duty) before peak power, leaning the engine into a soft rev limit.
- Too big → idle pulses shrink toward the dead time, where metering is imprecise and idle mixture gets jumpy.
Position matters too: direct injection meters differently and tolerates higher pressures than port or throttle-body setups.
How to tune it¶
Size for your power target with headroom (aim for roughly 80–85% duty at peak power), but no larger than necessary so idle resolution stays good. Match the fuel pressure system to the injector and position you choose.
Rule of thumb
Match injector flow to power, not ego. Oversized injectors make a rough, hard-to-tune idle for no top-end benefit if you weren't maxing the smaller ones.
In the game¶
Injectors are selected on the Setup page; their live duty cycle and dead-time effects show on the Fuel page while running.