Reviews

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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BY Heather Fishel / LAST UPDATED ON May 26, 2021

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. Thanks to their upgraded, smarter technology, these innovative systems deliver more than improved efficiency — they also give you better fuel economy, 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 
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Summary
Summary

This Holley 550511 EFI kit can support up to 650 HP. It comes with a handheld EFI monitor and a self-tuning ECU.

Pros
Pros
  • Features an easy-to-use self-tuning system
  • Includes easy-to-replace oxygen sensors
  • Eliminates cold start, vapor lock, and hesitation issues
Cons
Cons
  • Master kit version that comes with a complete fuel system is more expensive
  • Assembling the kit requires automotive knowledge
Best Overall
New Holley Sniper 550511 EFI Kit 
Best Value
FiTech 30021 Go EFI System
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Summary
Summary

This EFI kit comes with everything you need to maintain the classic look of your carburetor by hiding the injectors.

Pros
Pros
  • 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
Cons
Cons
  • Decent mechanical abilities are required for installation. 
  • Doesn’t come with a fuel system
Best Value
FiTech 30021 Go EFI System
Honorable Mention
MSD 2900 Atomic EFI Master Kit
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Summary
Summary

Weighing only 16.14 pounds, the MSD 2900 Atomic EFI Master kit can easily fit multiple models.

Pros
Pros
  • 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
Cons
Cons
  • Battery charger needs to be plugged in for a long time 
  • Computer tends to drain the battery faster
Honorable Mention
MSD 2900 Atomic EFI Master Kit

Why Trust Us


All of our reviews are based on market research, expert input, or practical experience with most products we include. This way, we offer genuine, accurate guides to help you find the best picks.

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Benefits of Aftermarket EFI Systems

  • Eliminate the need for a carburetor. Carburetors need to be adjusted mechanically to control the rate of air and fuel flow. However, they can get out of tune over time and risk failure if they aren’t constantly adjusted. EFI systems eliminate the need for a carburetor and continue to regulate the air and fuel flow independently with computations provided by the electronic control unit (ECU). This requires minimal effort on your part in adjusting the system.
  • Lower fuel consumption. EFI systems are more fuel-efficient than carbureted engines. This is because the electronic system constantly adjusts the air to fuel ratio to ensure that optimal levels are delivered. Carbureted engines, on the other hand, may deliver an excess fuel to air ratio, which can lead to more fuel consumption. 
  • Meet the engine’s operating conditions. Your engine may have different fuel or air needs depending on the operating conditions. EFI systems can continuously monitor the operating conditions, and adjust the air to fuel ratio with respect to the ambient temperature, altitude, driving conditions, and other engine requirements such as cold starts or overrun conditions.  
  • Maintain optimal engine performance. Engines that use EFI systems often provide a higher torque than carbureted engines. EFI systems can optimize power, ignition timing, and air to fuel ratios across different engine speeds to promote consistent performance. 

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. 

Multipoint 

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.  

Direct 

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 

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 

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

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

Best Overall
New Holley Sniper 550511 EFI Kit

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. 

Best Value
FiTech 30021 Go EFI System

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. 

Honorable Mention
MSD 2900 Atomic EFI Master Kit

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.

Honorable Mention
Edelbrock Pro-Flo XT Electronic Fuel Injection Kit

The Edelbrock Pro-Flo XT Electronic Fuel Injection Kit is a wholly comprehensive aftermarket EFI system — and it’s one of the most complete you’ll find. Composed of high-quality components, this kit includes a Pro-Flo XT EFI manifold, a 90 millimeter throttle body, fuel rails, fuel injectors, an ECU, and a calibration mod. With bolt-on installation, this EFI system is ready to get up and running on your vehicle as soon as you take it out of the box. It arrives with base calibration, and you’ll easily be able tune it to suit your engine once it’s installed. The ECU is advanced and intelligent, with downloadable calibrations available to easily get different engines up and running. You can even customize the ECU’s settings to suit your exact specs. 


When it comes to reliable performance, this aftermarket EFI system is thoroughly tested to ensure it suits your expectations. All Edelbrock EFI systems are tested in real-world environments before leaving the factory.

Honorable Mention
Holley Performance Avenger EFI Multi-Point Fuel Injection System

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.

Honorable Mention
Fast EZ-EFI 2.0 Self-Tuning Fuel Injection System Kit

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.

Honorable Mention
Fi-Tech FIT-72002 Ultimate EFI System

The Fi-Tech FIT-72002 Ultimate EFI System is one wonderfully easy aftermarket kit to get your new fuel injection system installed and working smoothly. The bundle of parts includes an intake manifold kit with a 92 millimeter throttle body and electronic transmission control, along with everything else you need to install the system on your car. Designed to suit GM electronic transmissions — specifically the 4L60, 4L65, 4L80, and 4L85 models and small block V8 Chevrolet engines — the EFI system will actually control shift points, firmness, downshifting, and all the other elements you need. However, it’s totally optional, and you can utilize the EFI system without opting into the transmission control too.


One of the best features of this aftermarket kit is its intelligent technology. The EFI system is self-learning, which means it monitors and adjusts as needed once it’s installed. However, if you’d like to have more hands-on control, that’s also possible. The touchscreen control allows you to configure the system and make adjustments to suit your performance and power needs.

Honorable Mention
Nitrous Express Proton Plus EFI System

The Nitrous Express Proton Plus EFI System is a universal EFI option that utilizes nitrous, with a 10-pound bottle and the brackets needed to install it in place. This aftermarket option is a good choice for vehicles with lower horsepower, specifically between 3 and 125 horsepower. The bundle of components includes stainless steel brackets, all of the electrical connectors you need, nitrous oxide nozzles, steel braided hoses, a lightning bottle valve, and a billet aluminum solenoid box — plus all of the hardware necessary for installation right in your own garage.


With this nitrous EFI system, you’ll get a sleek set of durable parts, all of which feature black anodized aluminum housing that can survive heat and last you a long time thanks to its increased durability. You can choose what size nitrous bottle you’d like to use (from 5 to 15 pounds) and make adjustments now or later as you try the system out. Made to fit all electronic fuel injected vehicles, this kit can upgrade your current system without costing you a ton.

Tips

  • If you are planning to use a power adder (such as a supercharger) with your EFI system, you should consider a system that is compatible with your power adder.
  • If your engine is a new build, consider consulting with an engine-building professional before installing an EFI system.
  • 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 higher temperatures for a longer time. Make sure to mount it in a location where it can easily cool down.

FAQs

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, but it may not directly increase your horsepower. Most aftermarket EFI systems can handle engines with anywhere from 450 to 600 horsepower, but some are suitable for as much as 1,200 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.