24 May 2022
How Do Upgraded Fuel Injectors Increase Horsepower?

Upgrading your fuel injectors is one important part of increasing your engine horsepower. However, it's not the only thing you need to do to make your vehicle more powerful. Read on to find out how upgraded fuel injectors increase horsepower.

Higher Flow Rate Injectors Add More Fuel To The Cylinders

injector flow rate

If you increase the flow rate of the fuel injectors in your vehicle, your engine computer can use them to add more fuel to the cylinders. If this increased fuel can be mixed with an increased amount of oxygen, there will be more energy released during combustion, and the engine will make more horsepower.

In other words, higher flow rate fuel injectors make power by "putting more logs on the fire." Gasoline fuel needs oxygen to burn, and the more fuel that's burned, the more power that's made.

And while higher flow rate injectors are essential to making more power in a lot of engines, bigger (or higher flow rate) fuel injectors won't help your engine by themselves. If you increase fuel in the cylinder prior to combustion, you have to increase the oxygen in the cylinder too.

More Fuel Means Your Engine Needs More Air

Engine intake

If you want to maximize engine power, you need to mix gasoline and air in a very specific ratio - about 14.7 units of air for every unit of fuel. If you mix air and gasoline in this ratio, you can achieve "ideal" combustion, as you'll have the right amount of oxygen to completely combust all your gasoline.

While most engines don't quite hit this ratio (most engines run a little rich to prevent knock), it's a very important number for every engine computer. And if you're an enthusiast tuning up your engine, it's good to remember that putting 1 more milliliter of gasoline into the cylinder means finding another 14 (or so) milliliters of air to go with it.

There are a lot of things that can be done to increase airflow into an engine:

  • Upgrading the air intake system - including the main engine air filter - can help increase airflow a bit
  • Cooling the air before it enters the engine, so it's more dense (and therefore contains more oxygen) is helpful
  • Modifying the engine timing via programing the engine control unit (ECU) is very helpful
  • Increasing the boost pressure of a turbocharger or supercharger (there are a lot of different ways to do that) is usually very helpful
  • Adding a turbocharger or supercharger to the engine is always extremely helpful.

This post has more information about these options. The good news is that for a lot of newer turbocharged engines, there are lots of easy ways to increase the amount of air going into your engine that won't break your wallet.

How Much Horsepower Can You Gain With Higher Flow Rate Fuel Injectors?

injector horsepower

Generally speaking, the amount of horsepower you will gain with a set of higher flow rate injectors is proportionate to the size and power output of your engine. If you have a turbocharged 1.8L engine making 220 horsepower - for example - a small "bump" in fuel and air flow could easily yield a 10-20% horsepower increase, or about 20-40hp. But if you have a 300 horsepower 3.0L engine, a 10-20% increase would be 30-60hp.

Of course, every situation is different. These horsepower increases are just for example's sake, so it's best to do your research and work with a professional tuner to determine exactly what size fuel injectors you need. Sizing injectors correctly is important.

Are There Any Downsides To Installing Higher Flow Rate Fuel Injectors?

Generally speaking, there's no downside to upgrading your injectors, as long as your upgrade is done properly (meaning, the new injectors are right sized). That's because bigger injectors don't automatically decrease fuel economy, and often perform better than OEM injectors at higher engine speeds.

Because all TLF Performance injectors are flow rate certified, they often outperform the OEM or "stock" injectors when the engine is cruising, idling, etc. This is because many individual OEM injectors flow way too much fuel or not enough, which leads to excess fuel consumption and can even cause serious engine problems. For this reason, a set of our high performance fuel injectors might just make your engine more fuel efficient rather than less.

NOTE: You may be tempted to install the biggest fuel injectors you can find for your engine. We strongly advise against that. If you have injectors that are too big, they may over-fuel your engine, and potentially even cause problems. It's essential that the injectors you buy are appropriately sized for your engine and your specific modifications.

Are There Any Downsides To Using An Inexpensive Generic Fuel Injector?

inexpensive fuel injector

In a word, yes. We've seen hundreds of examples of low quality fuel injectors causing serious engine problems.

Most of the engine problems caused by fuel injectors are related to inconsistent fuel flow rates. Imagine you have a V6, and that all 6 cylinders have injectors flowing different amounts of fuel at wide open throttle:

  • Cylinder #1 flows 55lbs
  • Cylinder #2 flows 40lbs
  • Cylinder #3 flows 68lbs
  • Cylinder #4 flows 52lbs
  • Cylinder #5 flows 57lbs
  • Cylinder #6 flows 53lbs

You may be thinking "there's no way that a set of fuel injectors could have fuel flow rates that are so different," and if so you would be incorrect. We see this sort of thing all the time. In any given set of injectors - even brand new OEM quality fuel injectors - we will see wild swings in fuel flow rate in the same set of injectors. The issue is that most injectors don't use premium materials and aren't sufficiently tested after production, so they leave the factory being "off" as much as 50%.

From our example above, you can see that cylinder #32 is flowing 30% less fuel than every other cylinder. Odds are that cylinder is running really lean, risking engine damage. At the same time, cylinder #3 is flowing 20% more fuel than the next highest cylinder, which means it's wasting fuel.

The point here is that you want to make sure your injectors flow the stated rate. If they don't, they're costing you money.

We Have The Best Fuel Injectors You Can Buy

Every fuel injector we sell is precisely remanufactured and tested.

  • We replace cheap carbon steel components with stainless steel or titanium components
  • We use premium gaskets, filter baskets, and seals to maximize injector life
  • We put all our fuel injectors through a rigorous testing process, and they only "pass" if they score 99% out of 100%. This way, every injector is certified to flow precisely the right amount of fuel.

TLF Performance supplies injectors to race teams, custom engine builders, and even automotive museums (the world famous Peterson Automotive Museum buys from us, for example) because they know our quality is second to none.

And while you might be thinking that a remanufactured injector won't be as good as a brand new injector, we'd argue that injectors are only as good as the parts that go into them, and only as reliable as the testing indicates. We use the best parts and we test the hell out of every injector before it leaves our facility in Illinois.

Finding The Best Replacement Fuel Injectors For Your Engine

Whether you're replacing an older set of injectors whos' time has come, or you're upgrading your injectors to increase engine power, you want to start by finding injectors that are compatible with your vehicle year, make, and model. From there, you can find a set of injectors that work with your engine and also with any upgrades you've made.

To get started, all you need to do is do a search on our website for your vehicle's year, make, and model.

Finally, if you can't find the injectors you need because they're too old, too rare, or simply obsolete, contact us. We build custom fuel injectors, and we have made injectors for everything from older tractors to high performance aircraft. We test every custom injector the same way we test all of our injectors, and we stand behind them the same way the rest of our injectors too.