Holley Sniper Stealth 4500 EFI System

SKU: 550-84X Categories: ,


Complete Kit, Available in Multiple Finishes


Wanting to convert your dragster, bracket car, weekend warrior, or pro-street vehicle to Fuel Injection? Look no further! The Sniper Stealth 4500 EFI system from Holley features 8, 100LB/HR Fuel Injectors capable of supporting 800 to 1500 HP naturally aspirated, or 800-1250 HP on forced induction applications. The Sniper Stealth 4500 also features multiple input and output options for sensor inputs and switched outputs to control external relays. This system also comes with a USB to CAN tuning cable and free downloadable Sniper EFI Software to give you unlimited control of your engine.


  • Supports up to 1500 HP naturally aspirated or 1250 HP forced induction with eight 100 Lb/Hr injectors
  • Compatible with draw through or blow through forced induction applications
  • 2.125” throttle plates, flow 1440 CFM for large cubic inch engines
  • 2.5 Bar MAP Sensor
  • Integrated ignition timing control
  • Programmable launch control via 2-step and timing retard – both can be triggered by a trans- brake input
  • Gen 3 Ultra Dominator style 4 bolt air cleaner flange
  • -8AN Fuel Inlets
  • High Resolution full color touchscreen for initial setup, tuning, and gauge displays
  • Simple Calibration Wizard (Answer a few questions about your engine and it creates the base map, then starts tuning on its own!)
  • NO laptop required – Self-tuning ECU means you don’t have to be a computer/tuning wiz to have EFI!
  • The included Genuine Bosch LSU 4.9 Wideband Oxygen Sensor provides realtime Fuel Map Learn
  • Built-in single stage wet or dry progressive nitrous control
  • Three Programmable 0-5V sensor inputs for oil/fuel/dome or nitrous pressure or other critical information
  • Six programmable ground outputs, five programmable ground inputs. These can be used to trigger or control external devices such as nitrous solenoids, boost control solenoids. Or to provide the ECU with an Input to turn on functions.
  • One +5V reference output +5V power supply for 0-5V sensors
  • One sensor ground – ground supply for 0-5V sensors
  • Throttle body mounted ECU – no extra boxes to mount
  • Only 4 wiring connections required! (Battery +, Battery – , Switched Ignition & RPM)
  • Required external fuel pressure regulator, 12-848 is recommended
  • Customizable secondary fuel pump output (TPS, RPM or boost enabled)
  • User friendly Boost Control with handheld adjustability
  • Free software included comprehensive datalogging tool to help you maximize the performance of your engine
  • Real-time datalogging to the included 3.5” touch screen, allows you to save information to the SD card without needing a communication cable
  • Programmable target air fuel ratios per boost level
  • Advanced boost control available via free Sniper EFI tuning software, including Boost vs RPM and Boost vs Time
  • OEM Style TPS/IAC, for years of dependable service
  • Included clamp-on oxygen sensor kit ensures a leak free oxygen sensor installation, with stainless steel t-bolt clamps and a stainless steel (weldable) oxygen sensor flange

Additional information

Finish Option

Polish, Black, Gold


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Installation Instructions Click Here

Quick Start Guide