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Atomic EFI Carburetor to Fuel Injection Complete Conversion Kit

Our Products: Fuel Injection EFI Conversion Kits > MSD Atomic EFI Conversion Kits
SKU: MSD 2900
Brand: MSD
MSD / Atomic EFI #2900 Carburetor to Electron Fuel Injection Conversion Complete Kit (up to 525 HP) The Atomic EFI was designed to bolt on to any square bore, 4-barrel intake. This includes common 4150 and 4160 designs. These intakes can be found on countless engines for muscle cars and hot rods including small and big blocks by Ford, Chevy, and Mopar. There are even aftermarket intake manifolds to convert LS engines. More details...
Price: $2,428.60
Atomic EFI Carburetor to Fuel Injection Complete Conversion Kit
Atomic EFI Carburetor to Fuel Injection Complete Conversion Kit
Atomic EFI Carburetor to Fuel Injection Complete Conversion Kit
Atomic EFI Carburetor to Fuel Injection Complete Conversion Kit
Atomic EFI Carburetor to Fuel Injection Complete Conversion Kit
Atomic EFI Carburetor to Fuel Injection Complete Conversion Kit
Atomic EFI Carburetor to Fuel Injection Complete Conversion Kit
Atomic EFI Carburetor to Fuel Injection Complete Conversion Kit
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Product Details


MSD / Atomic EFI TBI #2900

MSD's Atomic TBI Fuel Injection Supports Nitrous and Boost

Throttle Body Kit (up to 525 HP)

Bolts onto any square bore 4 barrel intake


The Atomic EFI was designed to bolt on to any square bore, 4-barrel intake. This includes common 4150 and 4160 designs. These intakes can be found on countless engines for muscle cars and hot rods including small and big blocks by Ford, Chevy, and Mopar. There are even aftermarket intake manifolds to convert LS engines.


This is the complete kit for anyone planning to convert from a carburetor to Atomic EFI. You get the Throttle Body, Power Module (with Wide Band O2 sensor), Handheld Controller, and the Standard Fuel Kit for up to 525hp (at the crank).


MSD has led the automotive world in performance ignitions for over 40 years and now we are rewriting another industry standard. Using current aftermarket options to convert a vehicle to EFI can be difficult and time consuming but with the all new Atomic EFI, all that is going to change. Atomic EFI is a throttle body kit designed to update old engines with outdated carburetors to a fuel injection system with all of the modern benefits of EFI.
Atomic EFI was designed for the car guy. It can be installed by anyone with access to basic tools and a car with a 4-barrel carb. No laptop is required and the owner doesn't need to understand how to tune a fuel map because we do all that for them. In fact, we do a lot of the wiring for the user too! Instead of having countless sensors that have to be installed on the engine, we incorporate the TPS, MAP, IAT, and more right in the throttle body so the user never has to worry about them.
The best part of the Atomic EFI system is the returnless fuel feature. MSD uses pulse width modulation technology to control the fuel pump so that you only need one line. This means most users can keep their existing fuel tank pickup and never have to modify the gas tank. A small external Power Controller is required for the fuel pump and fans, but MSD implemented CAN-Bus technology to keep wiring minimized.

MSD's Atomic TBI Fuel Injection Supports Nitrous and Boost
El Paso, TX; June 27, 2013 - Since the launch of the Atomic TBI fuel injection system, one of the top questions we've received is whether or not the system would accept power adders such as nitrous and boost. The answer is YES! The Atomic TBI (and the new LS systems) can operate with power adders!
Setting up the Atomic for use with your favorite power adder is designed to be as simple as the initial programming. For nitrous fans, a wet system (one that supplies its own fuel to compensate for nitrous) must be incorporated. From the Atomic handheld monitor you'll be able to program a target air/fuel ratio that will be used when the nitrous is activated. There is also a timing setting that will retard the timing during nitrous activation as well.
For boosted applications, whether it be a blow through or draw through, the menu settings are similar. The throttle body incorporates a 2-bar MAP sensor and can manage up to 14-psi of boost. There is value for a target air/fuel ratio during boost on the handheld monitor as well as a timing retard that is based off timing per pound of boost.
An important aspect of using power adders with the Atomic TBI is to consider the fuel system as well as overall power levels. The injectors of the throttle body can support approximately 625 horsepower on naturally aspirated applications when used with the high horsepower fuel pump. Due to the increased fuel requirement on boosted applications the maximum horse power that the TBI is capable of supporting can be 20-30% less.

Frequently asked questions

What is the operating fuel pressure?
30-75PSI if you are using a PWM system (Pulse Width Modulated – Returnless system). If you have your own, regulated system required pressure will depend on horsepower. Most vehicles will use close to 45psi while cars pushing 600HP will need closer to 70psi.

If I already have a fuel system what pressure do I set?
Dependent on horsepower, most cars will require 45psi unless you are putting out very high horsepower. There is a DTC (diagnostic trouble code) that indicates 100% injector duty cycle. If this condition is hit, you will need to increase your fuel pressure by a slight amount (5-10psi) and try again. Please see instruction page 6 for more information.

What size injectors?
They are 80lb/hr @ 60PSI.

What fuels can I run?
The Atomic has been designed and calibrated to run on gasoline with up to 15% Ethonal added. It is safe to run E-85, but the calibrations will be wrong. All fuel tables, including start-up, normal run, and transients will have issues with E85 fuel. Only attempt to run E-85 if you are familiar with the common corrections for these issues.

How much current will the fuel pump and fan drivers support?
The fan drivers only support 1-2 amps meaning they will only drive the low current side of a relay. The fuel pump output can support 20 amps continually without the need for a relay.

Can a 16-24 volt system be used?
The Atomic is designed to run on 12 – 16 volts. Voltage should not exceed 16 volts, meaning a 16 volt system with an alternator is not supported.

What RPM inputs are accepted?
A magnetic, points or standard coil negative will work, but not a hall-effect 5V signal. The signal out of any MSD distributor or MSD Ignition Control Unit will suffice to supply an RPM signal for the Atomic. NOTE: An Ignition Control Unit is required with most applications.

What sensors are onboard and can I replace them?
There is a 2-bar MAP (Manifold Absolute Pressure) sensor, Fuel Pressure sensor, Inlet Air Temperature sensor, Throttle Position sensor and Idle Air Controller (IAC). The Throttle Position sensor is a proprietary non-contact sensor that should not need to be replaced. The Fuel Pressure, MAP, and IAC may be replaced by sending the units in to MSD if necessary.

What’s the CFM of the throttle body?
The Atomic EFI throttle body can flow approximately 1000 CFM. The horsepower is not limited by airflow – rather it is limited by injector size.

What exactly does the A/C RPM step up do and is it adjustable?
The computer tells the IAC to open when it sees a 12V signal on the A/C input line so it can open before the load is actually put on the engine, preventing the RPM from dropping. It does not actually raise the base idle RPM. It is factory pre-set and is non-adjustable.

Where do I set base timing when using the unit to control timing?
Under the "Initial Setup" screen on the Atomic EFI handheld, you will select "ENABLED" for Timing Control. Next, under "Advanced Setup", find parameters to set a timing curve. The Atomic is limited to 44 degrees of total timing (including vacuum advance) due to the limits of a distributor. For complete details and instructions on this, please see Page 15 of the instructions.

Can I plot a custom timing curve, and can I lock the timing out in the software?
Yes, you can set any base idle timing (minimum 500RPM) you would like, along with any total timing (minimum 1500RPM) you would like. In addition to this, you would be able to set a start RPM where the idle timing starts to advance towards total timing. You will also set the RPM at which timing reaches total timing. This will act like one of our distributor spring/bushing kits, but is not limited and can be set exactly. You cannot do a custom 3D timing table. No the timing curve cannot be locked out. The base timing can be set as early as 500 RPM and the fastest advance curve will end at 1500RPM.

Is there a start retard?
There is no start retard setting. However, if the Atomic is controlling ignition timing the Idle Timing setting entered in the system will be used during starting. If idle timing is set to 10 degrees that is what timing will be during cranking. For example, if the engine needs a lower timing for cranking, you can set your idle timing lower (i.e. 5 degrees). By beginning the timing ramp at 500 rpm with Total Timing at 35 degrees at 2000 rpm. This will create a retarded start with 2 degrees of advance 100 rpm through 2000. At an 800 rpm idle, ignition timing will be 11 degrees. This is one example of the many options available; always find the settings that will work best for the particular engine.

Is there vacuum advance?
There is a selectable vacuum advance from 0-15 degrees. It maxes out below 16” Hg manifold vacuum and is completely gone by 7” Hg manifold vacuum so it acts like a normal vacuum pot, only the total amount of vacuum advance is user adjustable, where as the rate of advance is non-adjustable. By setting the vacuum advance to 0, the vacuum advance is disabled.

What other timing capabilities does the system have?
The Atomic EFI has idle timing control since it is much faster than an IAC. The IAC is slow in responding to RPM changes compared to controlling idle speed through variations in timing to help maintain the idle RPM target. If you notice the idle timing jumping around, do not be alarmed, it is a normal function and will go away as soon as you touch the throttle.

What’s the smallest and largest CID that can be selected?
The Atomic EFI will support engines with as at least 100ci to 800ci (maximum).

Can injector size or fuel pressure be adjusted to accommodate larger or Small CID, or increased HP?
Injector size cannot be changed. If you are using your own system with a regulator, fuel pressure can be changed. A low horsepower engine would benefit from using a fuel pressure regulator and setting the fuel pressure lower. We have successfully tested a 305cid engine with 200 horsepower using the PWM system and the air fuel ratio was fine at 500 RPM.

What can be selected or adjusted via the hand held controller?
There are only a few things that must be changed between combinations.
Basic setup: Engine displacement, number of cylinders, fuel pump type (return or PWM), idle RPM, Rev-limit, timing control, three camshaft type selections (street, mild, performance)
Advanced setup: Fans (separate on temp for both fans), AFR targets (idle, part throttle, wide open), Ignition timing (curve settings), Pump squirt (0-100%)

Will the unit compensate for altitude and does the key need to be cycled to do so?
On altitude changes, the unit will compensate for altitude changes if you go above 50% throttle and are between 1200 and 3000 RPM. You can also cycle the key to the off position for 3 seconds which will have the same effect.

What type of Rev-limiter does the Atomic EFI use?
The Atomic uses a fuel cut-off rev limiter.

Does the unit increase idle speed and fuel for cold starting and warm up?
Yes. Cold start conditions will be automatically compensated for and will decay out as the engine warms up. By the time it reaches 145F, idle speed and fuel compensation are completely removed.

Will it hurt the unit to keep the key in the on position with 0 rpm for an extended period of time?
No, it will not hurt the unit. However, the WBO2 sensor will be drawing current the entire time for its heating plug. (NOTE: The O2 sensor will be hot if the key is left in the on position. Care should be taken to avoid burns).

How many pulses per crankshaft revolution are needed for the RPM input?
The Atomic must receive one pulse per combustion (4ppr on a V8).

How much current is the total system capable of drawing?
If both fans are on, the fuel pump is at full capacity the IAC is moving, and the injectors are at their maximum and the input voltage is around 10V it can draw as much as 30amps. Normal operation will be approximately 14-18 amps.

Will the system work on a 6 volt system?

Can the unit drive the coil directly?
No, the Atomic EFI doesn’t have a built in ignition driver and must be used in conjunction with an ignition box or a Ready-to-Run style distributor. Points and HEI distributors also need an ignition box to operate the Atomic.

Do the annular rings work the same as a carburetor?
No. The annular rings on the Atomic throttle body are designed by MSD’s engineers to work as special injector nozzles. The rings are not in a venturi and at no time does the fuel get pulled out because of low pressure. They help to spread the fuel out and have been shown to improve per cylinder fuel distribution. Even cylinder distribution, like that from a carburetor, helps make more consistent high rpm horsepower.

What are the HP capabilities of the system and what are the limiting factors?
With a large pump the maximum output of the Atomic is 625 HP. The limiting factor is the injector size. The Atomic EFI utilizes four 80lb/hr injectors.

How far can the pump be mounted from the tank?
The Atomic’s fuel pump should always be mounted as close to the fuel tank as possible. Using a return style system this is less vital, but a closer mount will aid in keeping the pump cool. Using a returnless style fuel system it is vital that the pump be as close as possible. With this system the pump MUST be within four feet of the tank – preferably two feet or less. The pump should always be at or below the bottom of the tank. The pump should be plumbed with the supplied 3/8” ID fuel line from the tank.

Is the pump supplied with the Atomic EFI Master Kit a puller / pusher or just a pusher style fuel pump?
The fuel pump is a "pusher” pump only which is what creates the limits on mounting options.

Is there a limitation to how long the CAN extensions can be?
The can extensions cannot exceed six feet in total length.

Is the unit susceptible to RF noise from other electronics and or the ignition system components?
The Atomic EFI utilizes shielded CAN and magnetic pick wires which help cut down on noise interference. Still, the wiring from the Atomic EFI should not be routed in close proximity of the spark plug wires.

What are the temperature limitations (hot and cold) for the system?
The Atomic EFI can withstand under hood temperatures in excess of 200*F and as low as 0*F.

Are the TBI, Power Module, and components water resistant or water proof in wet/ humid environments (or when washing the motor)?
The units are potted and are resistant to water intrusion although should not be immersed. Normal motor washing should be fine but never point a high pressure water source directly at electrical items.

Where is the unit made?
All research, design, programming, assembly, and final testing are done by our skilled technicians in El Paso, Texas.

Can it run an LS motor?
Yes, with the addition of a MSD PN 6010 box, it can handle the fuel delivery, but not individual coil spark.
If you are running a front mount distributor and single coil, you will be able to use timing control with an ignition box.

Does it require a phaseable rotor if I run timing control?
Yes. If you are running ignition timing control through the Atomic a number of other small items are required. Please see Page 15 for a list of required items.

Does the unit have a ported vacuum outlet?
Yes, there is a ported vacuum outlet on the throttle body. Customers can still use a stock distributor vacuum advance if desired.

What happens if the WBO2 sensor fails?
The handheld will display a DTC (Diagnostic Trouble Code) for the sensor. The engine will be allowed to continue running, but will use only the existing fuel tables. Fuel table adjustments or self-tuning will be deactivated.

Does a target AFR (Air Fuel Ratio) need to be set before start up or is there a base target AFR?
The Atomic comes with default Air Fuel Ratios that should be sufficient for most street based engines. However, if a change in AFR is desired the settings can be found in the "Advanced Setup” on the Handheld controller.

What is AFR (Air Fuel Ratio)?
An Air Fuel Ratio is the volume of air per each unit of fuel put into the engine. 14.7 units of air per 1 unit of fuel is "stoichiometric” meaning there is the exact right amount of air available to burn all of the present fuel. A lower AFR number means there is less air to match the fuel, and therefore the engine will run "Richer”. Oppositely, a higher AFR number means that there is more air to match the fuel and the engine will run "Leaner”.

Air Fuel Ratio scale-

Can I install larger injectors?
No. The Atomic EFI will not accommodate different sized injectors.

Can it be set up as a dual quad?
No not at this time. There are a number of changes that will need to take place before this is an option.

If I use a bigger pump, will it work up to 800?
No, the injector duty cycle will still max out.

Is the Atomic EFI UL approved for marine use?
No. The Atomic EFI is not UL approved at this time.