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MSD’s New & Improved Atomic 2 EFI System Offers EFI Drivability with Simple Installation

Author: Jason Reiss | 03/24/2021 < Back to Motor Life Home
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When MSD’s original Atomic EFI fuel injection system debuted several years ago, it ushered in a new era of fuel-injected performance. The end-user received a throttle-body fuel injection system, a separate, easily programmed engine control unit, and supporting components that a hot-rodder could install in a home garage. The system gave hot-rod and muscle-car owners a chance to add electronic fuel injection and provided a way to ditch ancient carburetor technology and move into the world of easy startup, smooth idle, and vastly improved drivability.


As time marches on, products become more robust, computer chips shrink in size, machining capabilities get better, and existing designs are improved. The Atomic 2.0 electronic fuel injection system is all-new. It offers massive improvements in a smaller package with a more robust interface when compared to the capabilities of the original Atomic EFI system.


The Atomic 2.0 EFI bolts right into place of a traditional 4-barrel 4150-style carburetor and uses the same style cable linkage, so existing throttle cables should link right up to ensure an easy installation. Let’s dive into the details of what makes it unique among aftermarket throttle-body style fuel injection systems and how the Atomic 2.0 is different from the original Atomic EFI system.

What makes it unique?


The Atomic 2.0 EFI system offers powerful self-learning tuning capabilities and MSD’s engineers improved the self-tuning wizard with updated calibration information that will quickly get your car or truck running. After installing the system into the vehicle, the end-user hooks up the all-new, color 3.5-inch touchscreen, answers a few simple questions about the engine and starts the vehicle. Then, the self-learning function will use feedback from the system’s Bosch LSU 4.9 wideband oxygen sensor to gather information and fine-tune the operating parameters all on its own. The touchscreen can also be mounted in the car for easy access and used as a gauge display.


Atomic 2 oxygen sensor installation

There are two options for installing the Bosch LSU 4.9 wideband oxygen sensor. The user can weld a bung into the exhaust pipe or use the clamp-on bung for easy installation if welding is not an option.


“It’s a weekend install; you have to install the oxygen sensor bung and the fuel pump setup. You’re typically going from a mechanical pump to a high-pressure electric pump,” said MSD Merchandising Manager Colin Kinser.


“There are a couple of options — you can drop the tank and install one of Holley’s Retrofit EFI Fuel Pump Modules if the tank is compatible. Holley also offers fuel tanks with in-tank fuel modules designed for old muscle cars and trucks. If the customer doesn’t have that option, the pump mounts outside the tank as low as possible, level to the tank bottom.”


Atomic 2 handheld with setup wizard displayed

The handheld control unit makes it easy to get the engine up and running; select the number of cylinders, engine size, target idle speed, camshaft type, and ignition type, and the system then creates a startup calibration so it can begin self-tuning.


A quartet of 100 lb/hr fuel injectors means the Atomic 2.0 EFI can support up to 650 horsepower in a naturally aspirated application or up to 635 horsepower in forced induction vehicles. The original system used 80 lb/hr injectors and supported only 625 horsepower only when coupled with the high-horsepower fuel pump kit. The updated design uses a throttle body that flows 865 cfm through its 1.750-inch throttle plates. The roller bearing throttle shafts are also new to the Atomic 2.0 and allow for smooth, easy throttle movement.


The throttle body injection configuration relies on the fuel injectors to deliver fuel through annular boosters, similar to a traditional carburetor. MSD engineers used this improved booster design to disperse the fuel more effectively as it enters the intake runners.


Atomic 2 Overview Tuning Table

Tuning the Atomic 2.0 EFI with a laptop gives the user ultimate control over the fuel map, timing table, and several other parameters like the rev limiter and launch retard. The flexibility of the system makes it an excellent choice for those getting started with laptop tuning and the handheld, self-learning feature is present for those uncomfortable tuning themselves.


The Atomic EFI 2.0 offers true laptop tuning — a first for the Atomic lineup. The Atomic 2.0’s updated capabilities include laptop tunability for that user who wants to maximize performance. The EFI interface is intuitive and provides fine-tuning options for those unique engine combinations. Along with laptop tuning comes the ability to data log the engine’s parameters to help dial in the tune-up. Those users with nitrous engines will need to use a laptop to finalize the tune for nitrous operation, regardless of whether they are using wet or dry nitrous injection.


“The user can tune the Atomic 2.0 EFI with a laptop by downloading the Atomic 2.0 EFI software from our website. However, the user will need to have an understanding of the parameters they are changing and why,” said Kinser.


Unlike the original Atomic EFI, the Atomic 2.0 EFI doesn’t require any permanent modules installed in the vehicle. The original Atomic EFI has a separate Power Module that must be mounted close to the throttle body in the engine compartment, which means more installation complexity than the new Atomic 2.0 EFI unit which packages the ECU ergonomically inside the throttle body housing.


Atomic2 Throttle Linkage

The throttle linkage for the Atomic 2 has linkage provisions for GM three- and four-speed automatics, Chrysler's TorqueFlite and Ford C4 and C6 kickdowns.


The ECU has been integrated into the side of the throttle body housing to simplify installation and ease of use. The throttle body housing also contains essential components like the throttle position sensor, Idle Air Control motor, and fuel pressure sensor. By positioning these sensors in the throttle body housing, MSD has made it easier for the end-user to install the system. Atomic 2.0 requires just four connections — Battery +, Battery –, Switched Ignition, and RPM — to function correctly. That’s half as many connections as the old system needs.


The powerful system has built-in fuel pump control with a 40 amp relay and can control an electric fan with ease. The Atomic 2.0 includes an internal fan controller; the user specifies a fan activation temperature through the ECU and does not need an external controller. MSD engineers also outfitted the Atomic 2.0 system with an integrated ignition timing controller, when used with the included ignition coil driver, so the user doesn’t need an external ignition box to light the spark plugs off. They will also have full control over timing maps and ignition advance/retard under boost or with nitrous, should they choose.


The Atomic 2.0 is also compatible with MSD, Holley HyperSpark, and OEM ignition systems should the user want to retain those items if they are already installed. And adding one of Holley’s new digital dashes is a snap, too, along with any other Holley gauges or fuel system accessories.


Atomic 2 wiring harness

MSD has boiled down all of the critical electrical connections into this simple harness that needs battery power, switched ignition power to turn it on, and an RPM signal. The rest of the essential circuitry is baked right into the ECU inside the throttle body.


“Atomic 2.0 has multiple inputs, Magnetic Input, Hall-Effect, and Tach input. Depending on how the customer wants to connect the Atomic and if he is looking to control timing with Atomic will depend on how he connects the unit,” said Kinser.


Keep in mind that the Atomic 2.0 EFI needs a regulated fuel system to ensure the injectors receive the proper fuel volume. They require 60 psi of fuel pressure to operate efficiently, so MSD engineers have developed a turnkey solution in the form of the Atomic High Horsepower Fuel Kit (p/n 2921) and Fuel Pump Return Kit with Regulator (p/n 2922). These two items include all hoses, clamps, and fittings to supply the Atomic 2.0 EFI with the fuel it needs.


The Atomic EFI 2.0 is available in black ceramic (p/n 2910-2BK) or raw (p/n 2910-2) finishes and fits neatly under standard air cleaners — which means your buddies won’t think anything is different until you drop the hammer on them at the track.


“The Atomic 2 EFI provides the performance and drivability benefits that you expect from fuel injection. Quick starts, smooth idle, and great throttle response, just to name a few,” said Kinser.

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