Carburetors have been the core of automotive industry as well as its aftermarket, performance and racing segments for over a century. Their successor – the Electronic Fuel Injection (EFI) burst onto the scene in the 1980s and by mid 1990 had become the industry’s main fuel delivery system.

The old faithful carburetor hasn’t disappeared though, it continues to be the preferred choice within certain automotive markets like the muscle car and hot rod community.

Carburetors continue to be popular among the muscle car and hot rod enthusiasts.

While today’s traditional car builders, racers and restorers are comfortable with technology, it still takes a big leap of faith for someone who has spent decades changing jets and turning mixture screws to start tuning with a laptop computer.

The aim of this article is to demystify EFI and explain how it differs from a carburetor.

How EFI works

An EFI system consists of a fuel pump, fuel injectors, sensors and an Engine Control Unit (ECU). Fuel gets pumped up from the tank via a fuel pump out to a fuel injection rail, then into individual injectors which are inserted directly into the intake manifold. The fuel injectors are controlled by the ECU.

Fuel injectors are mounted in the intake manifold and are controlled by the ECU.

How ECU works

A number of sensors plugged into the ECU monitor all important engine data. Things like air temperature, manifold pressure, throttle position, RPM are all collected and analyzed by the ECU in order to determine how much fuel to supply to the engine.

An ECU like Haltech’s Elite shown here, monitors all the sensors and controls the amount of fuel provided to the engine.

Tuning with EFI

EFI tuning is done on a laptop via a dedicated ECU software. Rather than adjusting carburetor jets, the tuner customises “fuel maps” which tell the ECU when, how and how much fuel to provide to the engine. This allows the tuner to map fuel delivery throughout the entire rev range.

A fuel map allows the tuner to specify the exact amount of fuel throughout the entire rev range.

Advantages of an EFI system

Because the ECU constantly monitors all the sensors, an EFI system is infinitely more tuneable than a carburetor. No more stuck float bowls after winter, no more flooded engines on cold mornings, no more fouled plugs, no more rough idle or vapor locks on hot days. These things are all a distant memory with EFI.

As an EFI system is controlled by one, single box, its wiring is also simpler and safer.

Pro Mod racer Bill Lutz successfully uses Haltech’s ECU system on his twin turbo Camaro.

The benefits for racers are even more impressive; data display and logging, multi stage dry nitrous injection control, boost mapping, traction control, knock control, launch control and anti-lag, even engine shutdown protection are all available to an EFI tuner.

Mike Jovanis uses a Haltech ECU in his NMRA True Street turbo Mustang.

Upgrading from carburetor to EFI

While every EFI setup is different, a basic upgrade involves replacing the carburetor with a throttle body and installing injectors in the intake manifold. The next step is to install all the necessary sensors (a common install includes an oxygen, manifold pressure, air temperature, coolant temperature and throttle position sensor). All the sensors are then connected to the ECU and the system is ready to tune.

A carburetor sitting atop an inlet manifold is soon to be replaced by….

… an EFI throttle body.

Why go with Haltech?

Haltech is a world leader in engine management technology and we are focused on not only providing user-friendly products but also educating the users on how to get the most out of their systems.

Haltech ECUs are at the cutting edge of EFI technology proving their worth at race tracks and drag strip around the world.

Haltech’s technical support is second to none and backed by an extensive online knowledge base. We don’t just sell products, we stand behind them and support their users.

Street Outlaws’ Dominator is one of the most recent converts to Haltech and EFI.

In order to move up the list, Dominator’s old system (above) had to be upgraded to EFI.

With a little help from Haltech tech crew, Joe’s car was transformed into a fire breathing, high-tech, EFI monster.

Brand new throttle bodies replace the old carburetor.

The new setup also included a multi-stage, ECU-controlled dry Nitrous injection.

In the video below Matt explains the basics of a carburetor system and compares them to those of an EFI fuel delivery method.

Want to know more?

Go to Haltech’s YouTube Channel
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