-37% Sniper XFlow EFI System

The Gap-Filler

Those of us who have followed the development of the Sniper EFI System had identified a gap in the product line some time ago. The 800 CFM 4150 Sniper was only appropriate for naturally aspirated engines up to about 700 HP--and only then with the eight-injector version. And the massive 1440 CFM provided by the 4500 Sniper Stealth wasn't even recommended for engines making less than 800 HP.

So what is the engine in 650-800 naturally-aspirated HP range to do?

Consider the problem solved by Holley's new Sniper XFlow EFI System. First, Holley has punched out the 4150 throttle body to flow a much more filling 900 CFM of air flow. Then, they've upgraded the injectors from 100 PPH to 120PPH. This puts peak naturally-aspirated HP right at 800.

Boost & Nitrous Ready

Don't get the impression that the Sniper XFlow is limited to naturally aspirated engines. Holley has upped the ante there too, increasing the internal MAP sensor from 2 to 2.5 bar. And it has the same advanced boost and progressive nitrous control features as the rest of the Sniper EFI line. So if you're ready to boost, bring it. The larger injectors in this Sniper make it good to about 650 boosted HP on gasoline.  Or opt for the eight-injector version and boost or dry-spray nitrous up to 1375 horsepower on gasoline!

Same Installation-Friendly Features

If you have an engine with a Holley 4150-style intake manifold then you are ready to start installing. Bolt on the throttle body, put the linkage in place, connect the power and O2 Sensor, provide a regulated EFI fuel supply (External Adjustable Fuel Pressure Regulator 12-848 recommended.)  All that's left is walking through the guided setup quiz (with not-so-tough questions like, "what is the displacement of your engine") and the ECU located inside the throttle body itself does the rest.

Much In Common With The Super Sniper

Like the Super Sniper the new Sniper XFlow adds a 8-pin I/O harness to the two programmable inputs and 3 programmable outputs of the standard Sniper. This harness provides three more programmable inputs and three more programmable outputs, as well as sensor power and ground for a 0 to 5-volt sensor. That means the Super Sniper can monitor, log, and display fuel and oil pressure!

Another key feature shared with the Super Sniper is support for draw-through supercharger applications. The Sniper XFlow allows you to run a remote MAP sensor so that you can read the manifold pressure beyond the supercharger. They did this by tapping the existing MAP sensor port and including a 10-32 set screw. Install that set screw and a hosebarb, and then connect a vacuum line to the manifold. Easy!


  • Direct Fit for 4150-style Intake Manifold (adapters available for other manifolds)
  • The ECU is in the Throttle Body--No boxes to mount, no complex wiring harness to run!
  • Connect with as few as 4 wiring connections: Power +/-, Ignition, and RPM Signal
  • Visually amazing 3.5-inch touchscreen provides both setup and monitoring
  • Self-tuning--no laptop or software required!
  • Color Options: 550-540 Shiny Silver, 550-541 Ceramic Black, 550-542 Classic Gold

Sniper Laptop Tuning Software

People ask us what is the difference between entry-level EFI Systems.  The deal maker for us is the amazing Sniper software! Hey, what you can access and control via the included 3.5-inch touchscreen display is very impressive. This added software is not necessary for the vast majority of Sniper EFI users. But there are a few folks out there who wanted full-featured tuning capability. Well, here it is!

What can you do with the laptop software that you can't do with the handheld? Well, you can tune your Sniper to work with boosted engines up to 1.5 bar of boost (using the 2.5-bar map sensor that came on the Sniper) or configure an external MAP sensor to run even more boost. It is important to note that this software deviates from the basic concept of EFI for Everyman. While it is easy to attach the optional USB adapter cable, download the Sniper EFI Software, install, connect, and run, learning EFI tuning is challenging to say the least.  But we here at EFISystemPro.Com are excited to guide you in your learning.

Recommended With your Super Sniper EFI System

  • You will need an EFI Fuel System. We have several solutions!
    • A complete EFI Fuel Tank System is also a great choice. Be sure to opt for the 400, 430, or 450 LPH pump if you will be making over 630 NA HP.
    • If no complete Tank solution is available for your vehicle but you still want the benefits of an in-tank pump then one of these Retro-Fit Fuel Tank Modules is the right answer. In this case, opt for the 450 LPH version to get the fuel you need to feed the eight-injector Super Sniper.
    • If you have a racing fuel cell with a 6- or 12-bolt flange around the filler neck then one of these Fuel Cell Tank Modules is ideal, with fuel pump options providing over 1000 LPH!
  • You absolutely will want a way to confirm your fuel pressure.  The Fuel Pressure Gauge is a cost-effective solution but with the added Super Sniper you can add a Fuel Pressure Sensor, allow you to display and data-log fuel pressure. Those who don't install one with their EFI system are invariably the ones who end up needing it.  Don't be that guy!
  • The Super Sniper EFI System has the capability to control ignition timing in addition to providing fuel injection. If you choose this then we recommend you upgrade to the HyperSpark Distributor System.

What? No Master Kit?

Holley is not yet offering a master kit for the Super Sniper EFI System. And since the master kit for the original Sniper EFI System will only produce enough fuel for about 630 naturally aspirated horsepower on gasoline, that's probably not going to be enough for Super Sniper owners. But this is the goodness of buying from EFISystemPro.Com: Fuel systems are one of our specialities! We will gladly assist you with building a fuel system that is more than capable of feeding every horsepower that the Super Sniper is able to produce. Contact us to find out more!

Everyone says, "Buy From EFISystemPro.Com". Why?

When you buy it here at EFISystemPro.Com, that means we're on standby to answer your questions. Our level-3 tech support will gladly talk you through any challenge--just try to get that sort of personal service from a big-box auto performance store! Because here at EFISystemPro.Com, our look is high-end professional, but our service after the sale is home-town helpful!

Don't Miss This! FREE Sniper EFI T-shirt with every Sniper EFI system purchased from EFI System Pro!

This T-shirt is yours for $0.00 with your Holley Sniper EFI System purchased from EFI System Pro. Simply choose between Black and Dark Gray and designate your T-shirt size in the dropdown when adding the Sniper system to your shopping cart.

CLICK HERE for T-shirt product page

Watch This Great Video On The Super Sniper EFI System

Not Sure? Review this product documentation before you buy!

Owners & Installation Manual
Holley Sniper XFlow EFI System

Quickstart Manual
Holley Sniper XFlow EFI System

Wiring Tips
Holley Sniper EFI System

Boost ControlYes
DIS OutputsNone
Fueling StrategySpeed Density
Includes Power HarnessYes
Injector DriversFour or Eight
Internal DataloggingAll datalogging done via external CAN bus device such as 3.5-inch handheld (included), laptop software, or digital display.
Knock Control Channels0
Nitrous ControlYes
Number of Cylinders8 Cylinder (Even Fire Only)
User Configurable I/OYes
User-Selectable MAP StorageNo
Water-Methanol ControlNo
Displays And Controllers
Auto BrightnessNo
CAN Bus CapableYes (Specific to Holley ECUs Only)
Case/Bezel FinishBlack
ConfigurableMonitor dozens of pre-configured metrics provided by the ECU, including sensors, air/fuel ratio, switched outputs, drive-by-wire data, and more.
Data LoggingYes
Display TypeLCD
FunctionsSetup, Monitor, Tuning
Gauge/Display Size3.5 Inch Rectangular
Internal StorageYes (SD Card)
Throttle Bodies
Airflow Rate (CFM)900 CFM (at 1.5 Inches Hg)
Barrels (BBL)4
Gaskets IncludedYes
IAC Motor IncludedYes
Injectors IncludedYes
StyleThrottle Body Injection
Throttle Bore Diameter (ea)TBA
TPS Sensor IncludedYes
Fuel Injectors
Flow Rate (Lbs / Hr)120 PPH
Harness Type7-pin Power/Ignition/Fuel Pump, 10-Pin I/O, Wideband O2, Coolant Temp, CAN Bus (All fixed to Throttle Body), 8-pin Expanded I/O
TypeAir Temperature, 2.5 BAR MAP and Throttle Position (Integrated in TB); Coolant Temperature, Wideband O2
Also Included3.5-inch Touchscreen Display
ApplicationUniversal. Requires intake manifold for 4150 carburetor or adapter there-to. Also bolts onto QuadraJet intake manifold with the addition of sealing plate Weiand PN 9600.
ColorShiny Silver (550-540), Ceramic Black (550-541), or Classic Gold (550-542)
Emission Code3
Unit of SaleKit

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Sniper XFlow EFI System

  • Views: 33397
  • Brand: Sniper EFI
  • Product Code: 550-542
  • Availability: In Stock
  • $1,800.00
  • $1,133.96

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