In an earlier article discussing the different types of fuel injection, we touched briefly on some of the benefits of EFI* over a traditional carbureted setup.
* Although earlier mechanical fuel injection designs do exist, for the purposes of this article, when we say “fuel injection” we mean today’s electronic computer-controlled fuel injection systems.
When modern EFI systems started mainstream adoption during the 1980s, drivers immediately noticed an improvement in the cold-weather startup. Gone were the days of fiddling with a choke and feathering the throttle until the engine was warmed up—and for those of you who weren’t around for that era, that was a huge, huge advantage.
But one thing that earlier article didn’t cover much was the performance benefit. And since this blog is Powered by Summit Racing, we figured that was a topic best addressed in a standalone article…
…so here we are.
Does Fuel Injection Add Horsepower?
By itself, fuel injection doesn’t necessarily add horsepower. All fuel injection is, is a method to deliver properly atomized fuel into an engine. And as history points out, that’s a job that is just as easily handled by a carburetor.
At·om·ize – The process of converting a substance into very fine particles or droplets.
Granted there’s a ton of engineering nuance behind that statement, but in the name of brevity, switching from a carburetor to, say, a throttle body EFI system alone won’t gain you any significant numbers on the dyno.
The magic of a modern fuel injection system lies elsewhere, namely in tuning. So let’s talk about that.
The Performance Benefits of Fuel Injection
We’ve already mentioned the startup and cold weather advantages of EFI, and those are directly linked to the fact that fuel delivery is controlled by a computer.
Thanks to a network of sensors that monitor things like airflow, throttle position, crank position, O2 in the exhaust gas, and coolant temperature, a modern engine control unit (ECU) can constantly learn and adapt to determine how much fuel to deliver into the combustion chambers—or more specifically, how to precisely match that air/fuel mix based on the engine’s demand and operating environment.
And that’s a big deal, because cold engines require a different A/F mix when compared to an engine that’s already warmed up. More importantly for the performance-minded folks, an engine’s fuel needs change depending on engine speed and other environmental factors.
We alluded to “tuning” before, and that’s where EFI systems shine in the performance world.
Back in the day, performance engine builders were reliant on carburetor jetting to get a perfectly matched air/fuel mix. Not only was this a tedious job, it was still somewhat imprecise—especially when you consider dynamic fuel demands at different elevations and during different points along an engine’s RPM range.
Fast forward to today’s computer controlled fuel injection systems and engine tuners have a simply jaw-dropping amount of visibility and control of fuel delivery. This is a huge factor, because it means that a engine tune can be custom built around a specific engine’s fueling demands based on a specific set of criteria, like elevation, driving habits, and performance goals.
Fuel Injection Flexibility & Adaptability
And therein lies the beauty of a modern EFI system: adaptability.
Thanks to modern turning software, you (or your engine tuner) can optimize fuel delivery for your specific engine demands, which is especially helpful on an engine that’s been modified with, say, a new camshaft, a set of cylinder heads, or a power adder like a turbo or supercharger.
Outside of the engine tuning software itself, you’ve got even more flexibility with swapping in larger fuel injectors and adjusting fuel pressure to ensure adequate fuel delivery.
In other words, as you continue to modify and upgrade your engine in stages, you can adjust the fuel map accordingly.
That makes a fuel injection system a great first step to building a performance engine from scratch. Instead of having to adjust jetting as you modify the engine later on (or heck, even buying and swapping in an all new carburetor entirely) you can make smaller adjustments and modifications as you tailor your fuel demands to the present state of your motor.
Just for context, we’ve addressed the importance of air/fuel mix quite a bit here and that’s because it’s very, Very, VERY important to your engine—particularly when coupled with ignition timing (another parameter that can often be controlled by engine tuning software).
A rich condition (too much fuel) will result in things like poor performance and bad fuel economy, while a too lean condition (not enough fuel) can increase cylinder temperatures and potentially cause serious damage to your piston heads. (To be fair, these issues aren’t exclusive to EFI; they’re equally true if you’re running a carburetor.)
The good news is, most modern EFI systems incorporate safeguards like anti-knock sensors that efficiently safeguard against the more serious problems associated with an improper air/fuel ratio.
Should You Convert Your Old Car to Modern Fuel Injection?
Let’s make one thing clear: The purpose of this article wasn’t to dunk on carburetors.
Frankly, we like carbs around here. A lot.
When properly installed and set up, carburetors work great—there’s a reason they’re still in use today, and why you still see a massive selection of performance carburetors available in the automotive aftermarket
That said, from both a performance and a drivability standpoint, a modern throttle body EFI conversion has a ton of upside for a classic car or truck owner. While admittedly the process for converting an older carbureted car or truck to modern fuel injection isn’t as simple as plopping a new module atop the intake, you no longer need to be a computer engineer to figure it out.
In fact, once installed, many modern kits use a handheld controller with an intuitive setup wizard to walk you through the process via a few simple questions—after that the ECU self-learns to optimize itself as you drive.
Get a good look at the EFI conversion process from start to finish in this in-depth tutorial video from Summit Racing:
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Fuel injection is a complex and nuanced topic, so we have plenty of more resources to help you better understand how to service and upgrade your EFI system. Check out the links below to get started.
- 5 Things to Consider When Converting to Electronic Fuel Injection
- EFI 101: Mass Air vs. Speed Density
- How a Direct Injection Engine Affects Your Oil
- Will My New EFI System Work With My Setup?
- How Electronic Fuel Injection (EFI) Affects Cam Idle
- 3 Reasons to Consider a Self-Learning Fuel Injection System
- Fuel Pressure Ratings & How They Affect Your Engine
We also spoke with the fuel injection experts at Holley all about EFI conversions, troubleshooting, and general fuel system tech. Check out the whole interview in this episode of The OnAllCylinders Podcast:
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