Aftermarket Fuel System: A Guide to Fuel Injectors

While your Mitsubishi might be performing well enough with its stock parts, it’s no secret that many owners want to get more horsepower, torque and fuel efficiency out of their vehicles. There’s an entire industry dedicated to improving the performance of your vehicle – aftermarket parts. And there are quite a few parts that can accomplish that goal, one of which is the valuable, yet underrated fuel injector. Fuel injectors are Mitsubishi parts that boost your engine’s performance and help fuel economy. They accomplish this by delivering more fuel into the engine’s combustion chamber, where the fuel is burned with the help of air. 

While more fuel doesn’t automatically mean more power, you’ll find that modified vehicles often run lean as the engine can’t get enough fuel, resulting in a loss of power. Performance fuel injectors can deliver that fuel, preventing this from happening and giving you back the power that was lost. Fuel injectors regulate the amount of fuel sent to the engine with the help of a regulator. They replace the outdated carburettor systems which served the same purpose, but weren’t as fuel efficient and were dangerous to the environment. There are two types of fuel injection systems – electronic and mechanical. Most modern fuel injectors are electronic, as they’re easier to tune to your Mitsubishi’s specific fuel needs. 

Stock fuel injectors are tuned to deliver the right amount of fuel to stock engines. However, modified engines, or those with added turbo or superchargers, struggle to get enough fuel, resulting in a performance loss. This is because turbos and superchargers allow more air into the combustion changer, so there will be a lack of fuel. But before you buy these Mitsubishi parts, you need to take into account your Mitsubishi’s modifications and requirements. 

close-up of Bosch fuel injector

For gasoline fuel, you’ll need approximately 15 parts air to 1 part fuel. Of course, there are minor deviations based on the workload of the engine and road conditions. Diesel engines, on the other hand, require 1.45 parts air to 1 part fuel to run lean, mainly because of the specific way diesel engines burn the fuel. These ratios are required to achieve the stoichiometric point, which is when all fuel is burned and all oxygen is used in the combustion chamber. Your Mitsubishi’s ECU monitors and manages the amount of fuel and air that goes into the combustion chamber.

As briefly aforementioned, in stock vehicles, fuel injectors operate at about 80% capacity, which is enough for everyday driving. Vehicles outfitted with aftermarket parts, however, have the fuel injectors operating at maximum capacity. Turbo vehicles, on the other hand, require an upgraded fuel system with aftermarket injectors and fuel pumps. Stock injectors and fuel pumps just can’t flow enough fuel to the engine to make it operate at maximum capacity. 

It’s important to match the fuel injector to the engine, so before you buy one, check how much NOS you want to add to your vehicle. This is because fuel injectors that add more fuel than your engine needs can disrupt performance, just like the fuel injectors that don’t add enough fuel. Use an online fuel injector calculator to find out how much fuel your engine needs. Of course, you want the fuel injector to match your vehicle’s specific model and make for a seamless fit.
Even then, you won’t get the best performance possible. You’ll probably need some, if not all of these aftermarket modifications and parts:

  • Tune the ECU. The ECU is your car’s computer. So if you’re going to implement aftermarket parts that modify how the engine works without modifying the ECU, you won’t get the desired performance. This is because the ECU will work using your vehicle’s stock modifications.
  • Aftermarket fuel pump. While it might not be a necessary modification, it’s typically recommended. High-flow fuel pumps provide more fuel to the engine to optimise fuel efficiency and horsepower.
  • Fuel pressure regulator. This is another part that isn’t always deemed necessary, but it’s highly recommended. This part, as its name implies, regulates the fuel pressure. There are adjustable models that are made to boost fuel efficiency.
  • Fuel treatment. If you’ve upgraded your vehicle’s entire fuel system, you should also upgrade your fuel. You can do this by getting fuel treatment or catalyst to get the most distance out of every refill.

If you’ve installed a new fuel system, there are a few symptoms to look for that may mean there’s a chance of malfunction. The most common symptoms are rough idling, slow acceleration, engine stalling, check engine indicator, odour in the fuel, and smoke coming from the engine. To prevent potential issues, it’s paramount the entire fuel system is installed properly. Also, know that quality performance fuel injectors aren’t cheap, so you should take care of them properly. The injector you go for will come with instructions on how to take care of it. Also, regular fuel maintenance like changing fuel filters every 25.000km or once a year is important.