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Best Aftermarket EFI Systems: Optimum Power and Efficient Fuel Delivery

These top aftermarket EFI systems will provide optimum power and efficient fuel delivery for your vehicle.

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BYHeather Fishel/ LAST UPDATED ON January 26, 2022

Thinking about upgrading your carbureted engine to an aftermarket EFI system? Electronic fuel injection (EFI) systems are becoming increasingly popular with car enthusiasts who want better efficiency and increased power. Adding an EFI system to your car can take your engine to entirely new heights, thanks to the digital technology that takes control of the air and fuel flow through a throttle, port, or direct injection process. These innovative systems deliver improved efficiency, helping you fill up less often.
Worried that converting your carbureted engine to an EFI system will be too challenging? With one of the best aftermarket EFI systems, it can be a fun project. You just have to make sure you do your research and choose an EFI system that suits your car, your engine, and your needs. Whether you’re looking for an aftermarket EFI system for your passenger car, light truck, or a race engine, check out our picks for the best options right here.

Best Overall

New Holley Sniper 550511 EFI Kit 

This Holley 550511 EFI kit can support up to 650 HP. It comes with a handheld EFI monitor and a self-tuning ECU.
  • Features an easy-to-use self-tuning system
  • Includes easy-to-replace oxygen sensors
  • Eliminates cold start, vapor lock, and hesitation issues
  • Master kit version that comes with a complete fuel system is more expensive
  • Assembling the kit requires automotive knowledge
Best Value

FiTech 30021 Go EFI System

This EFI kit comes with everything you need to maintain the classic look of your carburetor by hiding the injectors.
  • Eliminates vapor lock, flooding, and cold start issues
  • The more you drive, the more it adapts to your driving style
  • Can be mounted wherever you want to maintain the classic look of your carburetor
  • Decent mechanical abilities are required for installation.
  • Doesn’t come with a fuel system
Honorable Mention

MSD 2900 Atomic EFI Master Kit

Weighing only 16.14 pounds, the MSD 2900 Atomic EFI Master kit can easily fit multiple models.
  • Includes single fuel line self-tuning and built-in sensors
  • There is no need for bulky ECU
  • Has only eight wirings
  • Laptop not needed for programming
  • Battery charger needs to be plugged in for a long time
  • Computer tends to drain the battery faster
Best Aftermarket EFI Systems: Optimum Power and Efficient Fuel Delivery

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Types of EFI Systems

Single Point 

A single point injector or a throttle body injector has one injector mounted at the throttle body. Fuel is sprayed into the engine in rapid short bursts, which creates a buzzing noise when the engine is started. In comparison to a carburetor, this system has better cold start characteristics and is better at regulating the air to fuel mixture. 


Modern EFI systems typically use a multipoint fuel injector (MPFI). It has a separate fuel injector for each cylinder that sprays fuel directly into each cylinder’s intake port. The injectors can be timed to spray at the same time to all cylinders, or to coincide with the respective cylinder’s intake stroke.  


A direct fuel injector sprays fuel directly to the combustion chamber, instead of directing it to the intake valve in the case of a gas engine, or a pre-combustion chamber in the case of a diesel engine. This type of injector has a needle valve at the nozzle that’s operated with a solenoid to regulate the pressure of the fluid being delivered into the engine cylinder. Since they are installed so close to the cylinders, they are exposed to more heat and require higher-grade material that can withstand the high temperatures. This is why they are more expensive.  

Top Brands 


Holley is an automotive brand that has been making automotive fuel systems for over 100 years. It was birthed by Bradford, Penn., brothers George and Earl Holley in the late 1800s. Today, the company designs fuel pumps, intake manifolds, EFI systems, and millions of carburetors. A series of mergers throughout the years led to the absorption of other brands under its umbrella including MSD Ignition, Accel, Powerteq, and Racepak. If you would like to try out one of its products, check out the New Holley Sniper EFI Kit.  


FiTech is headquartered in Riverside, Calif., and makes some of the best fuel systems. Apart from making EFI systems, it also makes fuel pumps, fuel filters, fuel pressure gauges, and regulators. The FiTech 30021 EFI System and the FiTech 30005 Easy Street EFI are some of its best EFI systems with innovative designs. 

Aftermarket EFI Systems Pricing 

  • Under $1,000: The EFI systems within this price range are able to control injection timing according to the speed, load, and the type of driving the vehicle is experiencing. It’s possible to program them to optimize fuel consumption, especially in heavy-duty diesel engines. 
  • $1,000 and up: Most EFI systems are a bit on the expensive side, but that often means you are getting a reliable system that can create a program that will suit your specific application. Therefore, at this price range, you can expect to find an EFI system with a programmable control system that you can monitor and control from a separate handheld monitor. 

Key Features 

Type of System

Like we mentioned above, there are a few different types of EFI systems — single point, multipoint, and direct. When you’re picking out an aftermarket option, it’s important to determine which type fits your car and your engine the best. Each has its own pros and cons, and the design differs between the three types. The type you choose will affect everything from the installation method to the cost of the EFI system, so make sure to consider this key detail before spending a cent.

Size or Power Output

Once you’ve settled on a type of aftermarket EFI system, it’s important to look at the size or power output of those that you’re considering. This is critical, as the size needs to suit your engine’s airflow and fuel requirements to deliver the horsepower you want (or are used to). Having a system that meets your engine’s size, power output, and horsepower will ensure you get prime performance once it’s installed. Look at the power output of an EFI system’s injector, and think about the size of your engine. Often, it’s given in a range — for example, you’ll see a max horsepower rating of 275 to 400 for a stock engine size of 250 to 400 c.i.d. or 600 to 750 horsepower for a 350 to 500 c.i.d. engine size.


Technology is one of the biggest reasons to install an aftermarket EFI system on your vehicle. These systems have become increasingly smarter in recent years, and they’re nothing like the old EFI systems that required laptops and specialized computer knowledge to get your car at peak efficiency. Today’s systems are easy to install and run with impressively easy technology. To find the best and most up-to-date options, look for EFI systems that include self-tuning capability. You can also look for systems that include handheld tuners for easy management and adjustments.

Other Considerations  

  • Compatibility: Any aftermarket part you buy should be compatible with your vehicle to avoid fitting issues. The best way to get a suitable EFI system is to search for one by entering your vehicle’s year, make, and model. If for any reason that doesn’t work, try searching for your vehicle’s OEM part number, which is often indicated on the EFI system. 
  • Fuel: Consider the type of fuel your vehicle uses as well. Some EFI systems come with a complete fuel system consisting of a fuel pump and filters that may not work with both gas and diesel. 
  • Warranty: A warranty serves as proof that the EFI system was designed with high-quality materials. It will help you get a new EFI system or free services from the supplier in case the one you bought stops functioning due to defects in workmanship. 

Best Aftermarket EFI Systems Reviews & Recommendations 2021

Holley didn’t cut corners when it comes to upgrading the look of the Sniper 550511 over other Holley EFI systems, and that’s why it has a tougher look to it. The unit is made from cast aluminum with a black finish, and the injectors are enclosed in the unit while the ECU is mounted externally. This keeps the wiring neat since almost everything is built into one unit. Also integrated into the unit is an ignition timing control, a coil driver, and a pre-set fuel pressure regulator. 

The unit is rated for up to 650 horsepower, and is designed to replace any square bore or spread bore style four-barrel carburetor. What's more, it comes with a handheld, full touchscreen monitor, which you can use to tune the EFI system as you please. 

The main issue we take with this kit is that it doesn’t come with a fuel system, which translates to extra costs on your end if you decide to buy the master kit with the fuel pump. Also, you need decent automotive knowledge to install this kit. Despite that, it’s recommended for nearly any carbureted vehicle including off-road trucks, street rods, and muscle cars. 

The FiTech 30021 has an innovative patented design that maintains the classic carburetor look by hiding the injectors within the structure and having an externally mounted ECU. This self-tuning fuel injection system is rated for up to 550 horsepower, and is designed to eliminate cold start issues, vapor lock, hesitation, and flooding. 

The unit comes with an integrated ignition timing control, and a Bosch 4.2 wideband oxygen sensor for real-time fuel mapping and to help send out information to the ECU. The oxygen sensors come with a clamp-on kit for leak-free installation. In addition, it has a dual bolt pattern, and as a result, can fit in a 4150 square bore flange or a spread bore. Also, you get a high-resolution, full-color touchscreen that will help you set up, tune, and monitor the system.  

One issue with this model is that you need to have decent mechanical know-how to install the EFI and sensors on numerous points of the engine. Despite that, it’s perfect for an everyday driver since the more you drive the more it adapts to your personal driving style. 

If you have a muscle car or a hot rod, the MSD 2900 will be a great addition to eliminate cold start and idle issues. This will make your ride feel almost as good as new. This EFI system features advanced self-learning technology, which involves the constant analysis of the engine’s operating conditions to ensure that your vehicle rides smoothly and with minimal issues. It also comes with a monitor that can give you real-time data on the engine’s parameters. 

The unit has an ECU and sensors built into the throttle body with few wiring connections for a neat system. This also makes the unit less bulky than most EFI systems and, therefore, will be easier to install. Since it’s a Holley master kit, it comes with a complete fuel system including the fuel pump and a single fuel line. After installing it, your vehicle will experience quick starts, a smooth idle, and better throttle response. 

However, all the frills with this master kit don’t come cheap, as it’s one of the most expensive EFI systems on the market. Also, the ECU and monitor can take a toll on your vehicle’s battery.

If you want an aftermarket EFI system that’s versatile and built to last, even as you make changes and upgrades to your vehicle in the future, the Holley Performance Avenger EFI Multi-Point Fuel Injection System is a great choice. Designed for small or big block Chevrolet V8 engines, this EFI system suits stock, crate, and even custom-built engines. With this EFI system installed, you can improve or maximize your performance — and it’s completely customizable thanks to the Avenger’s self-tuning capability.

Whether you’re looking for increased everyday power or want race-worthy results, this EDI system allows you to easily adapt and adjust. It doesn’t require a laptop to configure; instead, it comes with a full-color OLED handheld tuner so you can tweak the basic parameters. This EFI system is highly versatile, as it can be upgraded in the future if you want to make further changes. It’s one that’s built to support your needs now and into the future.

If you don’t want to mess with the technical calibration and all of the computer knowledge involved in running an EFI system, then you’ll want to consider the Fast EZ-EFI 2.0 Self-Tuning Fuel Injection System Kit. This complete bundle includes everything you need to go from carburetor to fuel injection, with a 4150 bolt pattern and a higher-flowing, higher-horsepower 8-injection throttle body. Made for V8 engines with up to 1,200 horsepower, this kit makes going to EFI easy. You don’t need to be a tech whiz — there’s no laptop or tuning experience required to get this EFI system up and running. It actually self-tunes while you drive, though there is a smart color touchscreen device that you can hold or mount on your dashboard to stay tuned in.

There’s just one drawback with this aftermarket EFI system: the price. This kit doesn’t run cheap, and it’s one of the more expensive options available. However, with all of the benefits and its easy-to-use design, it can be a worthwhile investment for some drivers.


  • EFI systems require higher fuel pressure for efficient operation. Therefore, you should consider upgrading the fuel line to meet the EFI system requirements.
  • Usually, EFI systems do not include a fuel reservoir as compared to a carburetor that has bowls for fuel storage. Therefore, you should also consider installing a fuel tank designed for EFI systems.
  • The location of the fuel pump is very important because it cannot stand high temperatures for a longer time. Make sure to mount it in a location where it can easily cool down.


Q: How does an aftermarket EFI system work?

An aftermarket EFI system uses high-pressure fuel delivery to an injector. It also uses computer controls, and overall it increases the power and fuel efficiency of a vehicle. The whole system is controlled electronically.

Q: What do I need to install an aftermarket EFI system?

You will need throttle bodies, a suitable manifold, a fuel pump with high pressure, injectors, and a filter. Apart from this, you will also need a regulator, a fuel rail kit, ECU, and a return line to the fuel cell.

Q: Do I need to use air cleaners on an EFI system?

Yes, we recommend you use cleaners. Any standard aftermarket cleaner can be used.

Q: Is an EFI system better than a carburetor?

This depends on your vehicle, your engine, and what kind of performance you’re getting right now. For anyone who wants increased power and better performance, an aftermarket EFI system can be a great upgrade over a current carbureted engine. However, if you aren’t worried about performance or power, you may not really see a huge benefit from the cost of buying and installing an EFI system.

Q: How much horsepower does an EFI system add?

The horsepower is tied to the size of your engine and power output potential of the aftermarket EFI system you buy. Typically, an EFI system will enhance your engine's performance, but it may not directly increase your horsepower.

Final Thoughts

Our pick for the best overall aftermarket EFI system is the New Holley Sniper 550511 EFI Kit because it provides a great deal of functionality. For a budget-friendly option, you should consider the FiTech 30021 Go EFI System.