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Holley Terminator X Engine Management Systems 550-1221 Systems, X, Up to 8-EV6 Injectors, 8-Coils, Analog, O2 Sensor, Plug-and-Play, USB Tuning Cable, Ford, 4.6L, 5.4L, Kit

SKU: HLY550-1221

Engine Management Systems

Holley Terminator X Engine Management Systems 550-1221 Systems, X, Up to 8-EV6 Injectors, 8-Coils, Analog, O2 Sensor, Plug-and-Play, USB Tuning Cable, Ford, 4.6L, 5.4L, Kit

SKU: HLY550-1221

Engine Management Systems
A$4,369.26
LOW STOCK! Est Ship 4-7 days. HURRY! LOW STOCK. This item is in limited stock at one of our distribution centres. The ETA is the approximate time required to prepare your order for dispatch.
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Description

Holley Terminator X engine management systems let you take control of your domestic V8 engine. These kits give you complete charge of your engine and self-learning fuel strategies, along with the proven, race-winning technology of Holley EFI—all at a budget-friendly price! Every MPFI Terminator X features real-time fuel learn, high impedance injector drivers, an integrated one-bar MAP sensor—and four programmable inputs and outputs, ideal for electric fans, boost control solenoids, progressive nitrous control, and much more. All systems come fully loaded with base maps for common engine combinations to get you out of the garage and onto the road or track fast.

Features include:

* Holley EFI industry-leading, easy-to-use software suite allows full laptop access for advanced users
* Real-time fuel map learn—takes the guesswork out of tuning your base fuel table
* High-impedance injector drivers will safely power most standard injectors and Holley EFI injectors. (Will not control low-impedance injectors)
* Bosch LSU 4.9 wideband relays AFR information to the ECU for accurate reading and precise tuning control
* On-board one-bar MAP sensor is perfect for N/A or nitrous engine combos
* MAP sensor vacuum hose adapters
* 4 inputs: 12 V, ground, 5 V, and frequency
* 4 outputs: Ground, PWM for accessories
* Boost control: boost vs. time, boost vs. gear, boost vs. rpm, boost vs. speed, and boost safeties
* Nitrous control: single channel of wet or dry, progressive or non-progressive, rich/lean safeties, and target closed loop AFR; adjustable through touch screen
* Advanced tables: 4 x 1D tables, 1 x 1D per gear table, 4 x 2D tables, 1 x 2D per gear table
* On-board diagnostic LEDs allow you to identify any critical engine issues at a glance
* The compact ECU size allows you to mount it virtually anywhere. Remember, diagnostic LEDs must face up!
* Plug-and-play compatible with more Holley EFI accessories
* Available with or without a 3.5 in. touch screen LCD hand-held with easy-to-use calibration wizard; allows you to quickly build a base tune for most domestic V8 engines, as well as tuning and gauge display functions (not available with every kit)

Part Type

Engine Management Systems

Data: v4.2 - Upd: 2026-10-13 18:47:17

Specifications

Product Attributes - Brand
Holley
Product Attributes - Manufacturer's Part Number
550-1221
Product Attributes - Part Type
Engine Management Systems
Product Attributes - Product Line
Holley Terminator X Engine Management Systems
Product Attributes - UPC
090127084939
Product Attributes - Transmission Controller Included
No
Product Attributes - Boost Control
Yes
Product Attributes - Traction Control
No
Product Attributes - High Impedence Injectors
Up to 8
Product Attributes - Fuel Injector Connector Style
USCAR/EV6
Product Attributes - Coils
Up to 8
Product Attributes - Ignition Coil Connector
Ford 4.6/5.4 2-pin
Product Attributes - Analog Inputs
4
Product Attributes - Wideband Controller
Yes
Product Attributes - Wideband Channels
1
Product Attributes - CANBUS Enabled
Yes
Product Attributes - CANBUS Networks
1
Product Attributes - Knock Control
Yes
Product Attributes - Knock Channels
2
Product Attributes - Drive-By-Wire Capable
No
Product Attributes - VVT Control
No
Product Attributes - Nitrous Control
Yes
Product Attributes - Launch Control
No
Product Attributes - Engine Protection
Yes
Product Attributes - Flex Fuel Compatible
Yes
Product Attributes - Multi-fuel Capable
No
Product Attributes - Data Logger
Yes
Product Attributes - Oxygen Sensor Included
Yes
Product Attributes - Reluctor Wheel Tooth Quantity
35
Product Attributes - Display Included
No
Product Attributes - Handheld Controller Included
No
Product Attributes - Remanufactured
No
Product Attributes - Quantity
Sold as a kit.
Product Attributes - Notes
To use E85 fuel a flex fuel sensor must be purchased. 2 and 4 valve engines with Smart coils and EV6 injectors. Cannot program through EFI Standalone Digital Dash Kits.

Reference Information

Brand Name/s Holley
StreetFX SKU hly550-1221
SFX Item ID 4783419
Supplier Item Code 4783419
Manufacturer SKU 550-1221
Manufacturer UPC 90127084939
Alternative References HOL550-1221, 8-EV6, 8-Coils, 4.6L, 5.4L

Compatibility

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