Holley 550-604N HP EFI ECU & Harness Kits

Universal V8 Multi-Point Fuel Injection, Includes NTK Oxygen Sensor

Part Number: 550-604N

Looking for a plug and play alternative for your stock or built late model factory EFI engine? How about a replacement ECU for your older Holley C950? Holley has you covered. HP EFI ECU and harness kits are designed to be used with popular factory EFI engines as an alternative to the factory ECU and harness or as a replacement for your C950 ECU. The HP allows you to accurately control the fuel and ignition of your engine along with additional controls for nitrous, boost or water meth.

Features and Benefits

• Advanced idle, closed loop, and enrichment strategies allow for very stable operation
• Unique lb/hr based fueling strategy greatly simplifies and commonizes tuning
• Ignition Plug and Play with GM HEI, Ford TFI, magnetic and hall effect trigger, and other ignition systems. New Plug and Play applications in process. Custom settings can be configured to allow many other applications
• Two channel knock control sensor Inputs for both one or two wire knock sensors
• Speed density, Alpha-N, or combination fueling strategies
• ECU is fully potted and can be mounted in the engine compartment or interior
• Fully featured nitrous control eliminates the need for a separate nitrous controller device
• Lean or rich safety cutoff
• Internal data-logging standard with a huge 2GB of memory
• 4 Stage progressive nitrous control
• Works with 4, 6, 8 cylinder engines
• 4 Stage nitrous oxide control
• 4 Programmable high or low Pulse Width Modulated (PWM) outputs and 4 fully configurable inputs can be configured for use
• 1-5 Bar MAP sensor capability
• Controls both stepper and PWM Idle Air Control (IAC) motors
• Full timing retard/control configurability per stage based on RPM or time
• Allows for use of common OEM sensors as well as customer sensor calibration input
• Sealed automotive and marine grade connectors
• Individual cylinder fuel and spark control allows you to unlock your engine’s potential
• Can be configured “Wet” or “Dry” with closed loop feedback
• Integrated Water/Methanol injection control
• Integrated single channel wide band oxygen sensor control. Works with NTK or Bosch sensors
• Progressive control based on time, RPM, or boost, requires part # 554-111
• Uses Holley Water/Meth solenoids specially designed and calibrated for use with this EFI system to allow the user to enter Water/Meth flow as a percentage of fuel injector flow for Water/Meth tuning precision unmatched in the industry
• Turbo boost control
• Eight channel Distributorless Ignition (DIS)outputs capable of directly driving “Smart” ignition coils or Holley DIS coils. Will drive 2 wire coils with the addition of PN 554-112 high current coil driver module
• Dedicated fuel and oil pressure inputs
• Self-tuning fuel table strategy greatly simplifies tuning process
• Optional 5.7” full-color touchscreen LCD allows easy on-the-fly tuning, data-logging or can be used as an easy to see graphical gauge panel
• Eight sequentially driven 8:2 peak and hold injector drivers, capable of driving up to 16 low or high impedance injectors as a standard feature. Multiple staged injector strategies

ECU is certified to ISO 8846, SAE J1171 & United States Coast Guard Requirements for Ignition Protection & Fire Resistance. Holley HP EFI systems are equipped with 4 programmable inputs and 4 programmable outputs that are ideal for most vehicles with a single power adder. This feature allows the user to configure the system to support a wide range of controls including boost control, progressive nitrous, water/meth injection, speed inputs, fuel pump control, AC inputs, timing retard inputs and various other uses. When selecting an ECU, users need to ensure their planned controls can be run with the 4 inputs and 4 outputs as certain combinations may use more I/Os than are available. If more I/Os are required, users should choose the Dominator VMS. Software and firmware updates can be downloaded here for free.