The Holley HP EFI ECU and harness kit gives GM LS2/LS3/LS7 owners a plug-and-play way to control fuel and ignition, with room to grow into boost, nitrous, or water/meth control as the build evolves. Download a base map for a stock LS engine and drive, or dial in a turbocharged, nitrous-fed combination running on water/meth — the same ECU handles both without constant re-flashing.
Key Features:
- ECU certified to ISO 8846, SAE J1171, and U.S. Coast Guard requirements for ignition protection and fire resistance
- 1-5 Bar MAP sensor capability
- Laptop-programmable with a variety of included base maps
- Sealed automotive and marine-grade connectors
- NTK oxygen sensor recommended for leaded or methanol fuels, high exhaust temperatures, and forced induction
- ECU is fully potted for engine bay or interior mounting
- Self-tuning fuel strategy reduces time spent tuning
- More functionality than OEM or competing ECUs — boost control, nitrous control, water/meth injection, and more
- Simple plug-and-play installation into factory sensors, power, and grounds
- Optional plug-and-play handheld programmer, 5.7" touchscreen, and digital gauges available
- Kit includes ECU, harness, communication cable, software, USCAR (EV6 style) injector connectors, and NTK wideband O2 sensor
Specifications:
- Engine Platform: GM LS2/LS3/LS7
- Crank Reluctor: 58x
- Ignition Type: GM LS 58x
- Injector Connector: USCAR (EV6 style)
- Inputs/Outputs: 4 programmable inputs, 4 programmable outputs
- MAP Sensor: 1-5 Bar
- Oxygen Sensor: NTK
- What's Included: ECU, harness, communication cable, software, USCAR injector connectors, NTK wideband O2 sensor
- Part Number: 550-603N
Designed for GM LS2/LS3/LS7 engines with factory GM coils and a 58-tooth crank sensor. If more than 4 inputs and 4 outputs are needed, Holley recommends stepping up to the Dominator VMS.
FAQ
What engines does the 550-603N fit?
It's designed for GM LS2/LS3/LS7 engines with a 58x crank sensor and USCAR (EV6 style) injector connectors.
Do I need a laptop to use this ECU?
The ECU is laptop-programmable and ships with a variety of base maps, though an optional plug-and-play handheld programmer, 5.7" touchscreen, and digital gauges are also available.
What injector connectors does this kit use?
USCAR (EV6 style) connectors.
What's included in the kit?
The ECU, harness, communication cable, software, USCAR injector connectors, and an NTK wideband oxygen sensor.
Can this ECU control boost and nitrous?
Yes. It has 4 programmable inputs and 4 programmable outputs that support boost control, progressive nitrous, water/meth injection, and more.
