Holley · Part 550-903
Holley EFI Terminator X MPFI Kit - GM LS1/LS6, 24x Crank / 1x Cam, EV1 Injectors, 3.5" Touchscreen
GM Gen III LS1/LS6 V8 with 24x crank reluctor and 1x cam sensor; EV1 (Bosch Jetronic/Minitimer) injector connectors; drive-by-cable throttle body only (Terminator X non-Max has no DBW control); no transmission control.
$1,599.95
In stock in Corona. Free shipping in the continental US, or collect it at the shop.
No returns or exchanges on third-party hardware — the manufacturer’s warranty is the warranty. Returns policy
Emissions
What it is and what it fits
GM Gen III LS1/LS6 V8 with 24x crank reluctor and 1x cam sensor; EV1 (Bosch Jetronic/Minitimer) injector connectors; drive-by-cable throttle body only (Terminator X non-Max has no DBW control); no transmission control.
What it does
- Plugs into the factory LS1/LS6 24x engine sensors and EV1 injectors with no splicing of the engine harness
- Handheld wizard builds a base calibration; laptop software gives full table access
- Fuel table learns in real time from the wideband
- Spare inputs/outputs cover fans, boost solenoid, nitrous activation or a trans-brake
- Diagnostic LEDs on the case show power, run, wideband, TPS, crank and cam status
Fitted and tuned on our hub dyno, or shipped to you
Buy it and fit it yourself, or have us do it. We install, wire and calibrate Holley engine management in our Corona shop and tune it on a Mainline ProHub hub dyno, with the full sheet at the end. Shop labor is $265 an hour, quoted against your car; the calibration is priced on the standalone tuning page.
It is in stock in Corona and ships free anywhere in the continental US. Alaska and Hawaii are quoted by phone. If you would rather collect it, or have it waiting here for your install, say so at checkout.
Specifications
Holley 550-903
- Brand
- Holley
- Part number
- 550-903
- Injector drivers
- 8, sequential, high-impedance (saturated) only - will not drive low-impedance injectors
- Ignition outputs
- 8 coil-on-plug outputs (direct drive of LS smart coils)
- Programmable inputs
- 4 (12V, ground, 5V, frequency)
- Programmable outputs
- 4 (ground / PWM)
- MAP sensor
- Internal 1-bar; external 2+ bar via GM 12592525 + Holley 558-416 adapter
- Wideband
- Bosch LSU 4.9 closed-loop control (LSU 4.2 not supported)
- Fuel learn
- Real-time self-learning base fuel table
- Boost control
- Boost vs time / gear / RPM / speed, with safeties
- Nitrous control
- 1 channel wet or dry, progressive or non-progressive, rich/lean safeties
- User tables
- 4x 1D, 1x 1D per-gear, 4x 2D, 1x 2D per-gear
- ECU size
- 7.45 x 4.1 x 1.66 in; diagnostic LEDs must face up
- Logging
- Internal to handheld SD card; laptop via free Holley EFI software
Questions
Before you buy
Is this the price other dealers charge?
Yes. $1,599.95 is the price authorised Holley dealers advertise, and DEFI is an authorised Holley dealer. Shipping in the continental US is free on top of that.
Will it fit my engine?
Read the fitment above against your engine, sensors, injectors and throttle before you buy. If anything is unclear — a part number, a connector, a transmission — call us first. That conversation is free; a wrong unit is not.
Can I return it if it is the wrong one?
No. There are no returns or exchanges on third-party hardware once it ships — the manufacturer’s warranty is the warranty. That is why we would rather answer the fitment question on the phone before you order.
Is it street legal?
Holley publishes no CARB Executive Order for this kit. It is sold for racing and for vehicles that are not emissions-controlled: it is not legal on a pollution-controlled vehicle registered in California, and a vehicle running it will not pass a smog inspection. We are not going to imply otherwise.
Can you tune it for me?
Yes. We calibrate Holley standalones on our hub dyno in Corona, and we can review logs remotely if the car is somewhere else.