Holley's New Dominator ECU Kits Offer More Features And Easier Installation

15 min read

Holley's New Dominator ECU Kits Offer More Features And Easier Installation

15 min read

Wiring is that panic-inducing side of hot rodding many of us dread. We often wake from nightmares of loose grounds or faulty connections. Well, Holley knows that pain, and developed Dominator EFI kits, to simplify the installation of the Dominator ECU on popular engine applications.

“This is one part number that a guy can get his car running without having to spec his entire engine,” said EFI Product Manager Colin Kinser. “What used to take us hours on the phone helping find every part number can now be done in just a moment.”

Colin has worked for Holley for several years, starting as a technician helping customers on the phone. “This cuts out hours of tech time or just the simple time of entering all the part numbers,” he says.

Dominator Kits include a Dominator ECU, USB cable, power harness, engine main harness, EV1 injector harness, Bosch Wideband, and ECU mounting hardware.

Dominator EFI LS1 550-650

The Dominator EFI Kit for LS1 (PN 550-650) is an easy installation and includes everything shown with the addition of mounting hardware. The harnesses are designed to be plug-and-play with pre-cut lengths and plenty of flexibility.

Available Dominator EFI Kits

Part NumberDescription 
550-650GM LS1
550-651GM LS2/LS3
550-654Universal with COP 
550-655Ford with COP
550-656LS1 with Trans Control
550-657LS1 with Trans Control and Drive-by-Wire
550-658LS2 with Trans Control
550-659LS2 with Drive-by-Wire
550-660LS2 with Trans Control and Drive-by-Wire

* COP = "coil on plug"


One of the biggest draws of a Dominator ECU is the quantity of inputs and outputs, the most in the Holley lineup. This allows racers to handle their entire tune from wheelie control to multiple fuel pumps. It provides more features and benefits then the competition, or other Holley ECUs, such as Terminator X, and HP.

Dominator Inputs/Outputs

  • There are 13 Multi-Inputs, which can be configured to the most common types (such as 0-5v, 0-20v, temp, or high/low voltage input)
  • A whopping 30, 0-5v sensor inputs
  • 4-speed inputs which can be configured as digital square-wave inputs
  • There are 20 12v PWM outputs and 16 ground PWM outputs

Dominator Features

  • Up to 4 Gb of internal storage dedicated to data logging.
  • Water/Meth control integrated, allowing for two nozzles and low-system safety features
  • Boost friendly with “boost builder” functions that help you make boost on the starting line
  • Capability of 1-7 bar MAP sensor, great for high boost applications
  • 8 Stage Nitrous control with lean or rich cutoff and wet or dry with close loop feedback
  • Integrated electronic transmission control
  • Integrated dual channel wide band oxygen sensor controls
  • Individual cylinder fuel and spark control

The Dominator uses “Pin Mapping” for inputs and outputs. A strategy that allows inputs and outputs to be pinned as desired by the user with user-programmable caution and warning outputs for all sensors.

The Dominator ECU is fully potted meaning it can be mounted in the engine compartment or interior. Both the power and main engine harnesses feature TechFlex F6 loom which provides protection and a sleek under hood look. The removable sub-harnesses, like coil and injector, provide quick serviceability and customizing.

Of course, fast is never fast enough, but the Dominator EFI Kits are an excellent way to future-proof your build, as Colin calls it. “You build this car with drive-by-wire and trans control and know you’ll likely add another fuel pump in the future, or maybe boost or nitrous control. You can start with the Dominator to future proof the install.”

Dominator EFI Kits will be offered engine-specific, not vehicle-specific, to work in any vehicle application. Generally speaking, kits will be available in multiple configurations such as with and without transmission control harness and drive-by-wire or drive-by-cable.

Already Own A Dominator?

For those who already have a Dominator ECU on-hand and want to adapt them to their specific application, Holley offers just the harnesses. See the list below:

Harnesses Only

  • TPI Stealth Ram Main Harness (558-101)
  • LS1 Main Harness (558-102)
  • LS2 Main Harness (558-103)
  • ’99-’04 Ford Modular (558-108) (with Holley Smart Coils 558-113)
  • Ford Coyote (558-110)
  • Terminator TBI, LSX 24X (558-111)
  • Terminator TBI, LSX 58X (558-112)
  • Early-Model HEMI (558-115)
  • Late-Model HEMI (558-116)
  • Ford MPFI W/Cop (558-118)

Universal Harnesses

  • Universal MPFI W/Cop (558-117)
  • Universal MPFI Main Harness (558-104)
  • Unterminated Main Harness (558-105)
  • Unterminated Flying Lead Harness (558-126)


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