24 May 2022
Why Is Fuel Injector Flow Rate Important?

When shopping for replacement fuel injectors, one thing you really want to be sure about is injector flow rate. A fuel injector's flow rate is a measure of how much fuel it can spray into a combustion chamber, and it's vehicle and engine specific.

When the injector fuel flow rate is correct, we have OEM-spec performance - your engine makes the power it's supposed to make, gets the fuel economy it's supposed to get, etc. And when the injector flow rate is wrong? All sorts of things can go wrong, from poor fuel economy to pre-detonation and engine damage.

Suffice to say, fuel injector flow rate is pretty darn important.

What Is The Fuel Injector Flow Rate?

Many people believe that fuel injectors are sized by their physical dimensions. That's a common misconception. Fuel injectors are actually sized by their flow rate.

The flow rate is the measure of fuel injected by a fuel injector over time. It's measured in pounds per hour (lbs/hr) or cubic centimeters per minute (cc/min). It's important to use the correct flow rate for your engine because it allows for the proper fuel to air ratio.

The flow rate describes the amount of fuel the injector can flow in a certain amount of time at a certain pressure. It's determined by several factors, including the fuel injector's physical size.An engine requires specific fuel injector flow rates throughout various phases of operation. The engine manufacturer determines these specific flow rates. Next, the manufacturer programs the flow rates into the electronic control unit (ECU). The ECU uses these values to determine how many pulses need to be sent to each injector to achieve the desired level of fuel delivery.

Flow Rate Is A Critical Fuel Injector Design Factor

The flow rate is an important part of a fuel injector design for two reasons:

1. The Fuel Injector Flow Must Be Uniform And Consistent

If the flow rate is not uniform or consistent, a variety of engine issues could arise. For example:

  • Pre-ignition
  • Poor engine performance
  • Poor fuel economy
  • Lack of acceleration

2. Fuel Injectors Must Be Able To Flow Their Maximum Rated Amount Of Fuel

In high performance applications or when the engine is running at a high RPM, the fuel injectors must be able to flow their maximum rated amount of fuel. If they're unable to, the engine doesn't generate the power it's supposed to generate.

If the injector fails to deliver its maximum flow rate, the fuel mixture will be leaner than optimal. This is not desirable, and will lead to poor engine performance.

The Importance Of Getting Injectors With The Correct Flow Rate

Every engine has designated injector flow rate settings at:

  • Idle speed
  • Part throttle positions
  • Wide open throttle (WOT) position

The amount of fuel required by your engine is determined by:

  • The engine's displacement
  • Power output demands
  • Engine speed (RPM)
  • Engine load
  • Different types of driving conditions (e.g. highway vs. city)
  • Intermittent demands, such as when accelerating from a stop or going up a hill

These factors determine the fuel injector flow rate your engine needs to perform at its best.

When you replace the fuel injectors in your engine, get ones that have the exact same flow rate as your stock injectors. The only exception is if you modify your engine to increase performance beyond the factory limits. In that case, you'll want fuel injectors with a higher flow rate than stock.

If you install a fuel injector that has a lower or higher flow rate, it can result in:

  • Pre-ignition
  • Detonation
  • Poor fuel atomization throughout operation
  • Damage to your engine

Make sure all your engine's fuel injectors have the same flow rate. If they don't, the engine will run rich or lean. Also, the maximum power output and maximum fuel economy will be lower.

TLF Performance Fuel Injectors Always Have The Right Flow Rate

At TLF Performance, we provide two types of custom remanufactured fuel injectors:

  1. OEM fuel injectors that match the stock flow rate
  2. Custom high performance fuel injectors with higher flow rates

When we remanufacture OEM fuel injectors, we make sure that they match the stock flow rate. We meticulously service all our OEM fuel injectors. We also put them through strict quality assurance tests (which most cheap injectors would fail) before selling them.
We modify our high performance fuel injectors to enable customized fuel flow rates. We do this while maintaining exact atomization of fuel particles. This ensures precise fuel flow to maximize performance with engine modifications.

When ordering high performance injectors from us, you can choose from a variety of flow rates. All of our fuel injectors come with a detailed fuel injector flow rate test report.

Please contact us if you need help finding the right fuel injectors for your application.