This guide assumes you have an existing, fundamental understanding of the general Holley EFI system.
Trying to determine which system your build is going need? Have questions? We’ll do our best here to guide you through the differences, and technical specs to aid your decision. This guide will pertain specifically to the Holley HP EFI, and the Holley Dominator EFI systems. There are other Holley EFI systems (Terminator, 950, Avenger, etc.) which are covered in other articles.
If you’re here to find out which system “makes more power” or “runs better”, stop reading now. Both systems, given the same programming and tuning, will perform exactly the same. The differences are strictly in capabilities, functionality, and quantity of inputs/outputs.
“CLIFFSNOTES”
If you don’t need electronic transmission control, drive by wire control, boost support over 5 bars (72.5 PSI), an extra 4 stages of nitrous control (HP Controls 4 stages, Dominator 8 stages), support for more then 16 fuel injectors, or multi map selection on the fly, you do not need the Dominator.
THE FEATURE DIFFERENCES
The HP and Dominator both share similar hardware and software archatecture. Differences range from input/output quantity, drive-by-wire and transmission control.
BOTH the HP and Dominator systems:
• Will control nearly all 4,6 or 8 cylinder engines
• Have integrated boost control, with boost-by-time, boost-by-gear, and boost-by-speed functionality
• Have integrated launch control with boost launch builder
• Boost scramble for additional boost settings on the fly
• Plug and Play control of GM 24x and 58x LS engines
• Control of the Ford Coyote Ti-VCT variable camshaft system (requires the separate Holley 554-145 control module found here)
• Provide traction control with power reduction via timing, nitrous or boost control (requires the Davis Technologies Holley Module found here)
• Integrated water/methanol injection control
• Advanced idle, closed loop, and enrichment strategies for stable idle and driveability control
• Two channel knock sensor control
• Can control stepper and PWM type idle air control valves
• Can be operated in Alpha-N, or speed density fueling strategies
• Dedicated fuel and oil pressure inputs
• Self learning fuel table functions
• Can-Bus output for Holley’s display, screens, gauges, and other accessories
Holley HP Specifics:
• 8 sequentially controlled, peak and hold injector drivers capable of running 16 low or high impedance fuel injectors with staged injection strategies available.
• Can run up to 8 distributorless ignition smart coils, or 8 “dumb” 2 wire coils (with the Holley 554-112 coil driver module found here)
• Built in single channel wide band O2 sensor control that works with NTK or Bosch sensors.
• Internal data logging with 2 gigabytes of storage
• 1-5 bar map sensor compatibility
• 4 stages of progressive nitrous control, with ignition timing control per stage plus lean/rich safety cut-off (requires Holley high current nitrous solenoid driver p/n 554-111 which is found here)
• 4 Programmable high or low PWM (pulse width modulated) outputs and 4 fully configureable inputs
The Dominator system adds features, functions and inputs/outputs to it’s capability list.
• DBW control, controls up to two drive-by-wire throttle bodies (compatible with most DBW bodies, including stock throttle bodies by GM, Ford, Nissan and Chrysler)
• Electronic transmission control (compatible with GM 4L60e and 4L80e as well as Ford AODE and 4R70W transmissions with more to come in the future.
• 13 “Multi Inputs” which can be used as 0-5v sensor input, 0-20v sensor input or thermistor temperature inputs
• 30 0-5v sensor inputs
• 4 speed inputs which can be configured as inductive or digital square wave
• 20 12v PWM (pulse width modulated) outputs which can be configured as standard switched or PWM 12v outputs.
• 16 ground PWM (pulse width modulated) outputs which can be configured as standard switched or PWM.
• Built in dual channel wideband O2 sensor control that works with NTK or Bosch sensors.
• 12 sequentially controlled, peak and hold injector drivers capable of running 24 low or high impedance fuel injectors with staged injection strategies available.
• 1-7 bar map sensor compatibility
• Store and select 4 individual tunes (with map selector p/n 558-407 available here)
• Internal data logging with 4 gigabytes of storage
• 8 stages of progressive nitrous control, with ignition timing control per stage plus lean/rich safety cut-off (requires Holley high current nitrous solenoid driver p/n 554-111 which is found here)
THE COST DIFFERENCE
The Dominator and HP systems share the same main power harness, and main engine harness. The additional functionality of the Dominator system comes from add-on harnesses through it’s additional connectors on the ECU itself.
The Holley HP is offered as ECU only or in several (plug-and-play) ECU + Harness and sensor packages. The Holley HP ECU base price is $1150 (ECU only) and the HP ECU + Harness packages are roughly $1600-$2000 depending on engine type, harness package and sensor combination. For $1600-$2000 you will have a running, tuneable engine with nearly all the features in the above list. All though the controls and software are in place, additional functions may require additional hardware and harnesses. Boost control hardware (solenoids, etc.), water/methanol hardware (pump, plumbing, valves, nozzles), Coyote Ti-VCT control, and traction control will require additional hardware and harnesses.
Dominator systems are typically offered as ECU only with all harnesses, add-ons, modules, and control systems purchased separatly. The Dominator ECU only base price is $2094, and will require, at a minimum, the following components.
• Dominator ECU itself p/n 554-114
• Main power harness p/n 558-308
• USB data cable p/n 558-409
• Either the universal MPFI main engine harness p/n 558-104 or the engine specific harness for your vehicle or engine combination. (harnesses found here)
• The injector connector harness depending on your injector configuration (injector harnesses found here)
• The ignition harness or distributor adapter for your specific application (adapter harnesses found here)
• Engine sensors and both wideband sensors (either Bosch style or NTK style, sensors can be found here. The Dominator operates 2 sensors of either type)
EXAMPLE COMBINATIONS
For comparison sake, below are two identical combinations for both systems, and their typical costs. If you have any questions, you’re welcome to call in, and have us guide you through your purchase.
Holley HP – Turbo GM LS2/LS3/LS7 – Manual Transmission
• Holley EFI 550-603 HP System LS2/LS3/LS7 (Includes all harnesses, cables and sensors) $1924
• Holley EFI 554-134 3.5 Bar screw in map sensor $126
• Holley EFI 557-200 3 Port boost control solenoid kit $114
$2164 = Fully functioning EFI with simple boost control, self learning, all harnesses, ready to tune.
Holley Dominator – Turbo GM LS2/LS3/LS7 – Manual Transmission
• Holley EFI 554-114 Dominator ECU $2094
• Holley EFI 554-101 Bosch Wideband o2 sensor $146 x2 = $488
• Holley EFI 558-103 LS2/LS3 Main engine wiring harness $453
• Holley EFI 558-409 USB programming cable $57
• Holley EFI 558-308 Main power harness $67
• Holley EFI 554-134 3.5 Bar screw in map sensor $126
• Holley EFI 557-200 3 Port boost control solenoid kit $114
$3399 = Functionally, this is an identical setup to the above HP example. The end result is again, a fully functioning EFI with simple boost control, self learning, ready to tune.
Above is only a simple comparison. Your combination and costs will vary, additional functions, drive by wire, electronic transmission control etc. will obviously require more hardware.
