While modern OEM fuel injection systems don’t require much consideration in stock engine configurations, sorting out a well-informed upgrade path can become a confusing proposition for enthusiasts who’ve added performance and discovered that their original injection system isn’t up to the task at hand.


With more than sixty years of combined experience among the staff, at Fuel Injection Clinic, they know a thing or two about fuel systems. As enthusiasts, they are also dedicated to the pursuit of finding higher horsepower, faster trap speeds, and lower lap times while maintaining reliability and drivability.

Based in Hobe Sound, Florida, Fuel Injector Clinic (FIC) produces high-performance fuel delivery systems for vehicles across all applications from foreign and domestic, to street and strip. These folks field a lot of questions over the telephone from builders who need a bit of guidance with their fuel system modifications, and a ready to assist.

We went over five of the most common questions, and misconceptions, about replacing and upgrading fuel injectors with FIC’s Jens Van Holten to help take out some of the guesswork.

What separates Fuel Injector Clinic from the competition?

Jens Van Holten: At Fuel Injector Clinic, we combine the highest quality injectors, match them precisely, include necessary tuning data, then we back it up with the best customer service in the industry.

Each dot represents one injector that was tested out of a large batch. Every injector was tested for both slope flow value and latency value, and this graph helps to illustrate how much injectors can vary from one another with only OEM matching, or even with basic matching. FIC precisely matches each set using our custom flow benches in order to offer consistent quality.

Each dot represents one injector that was tested out of a large batch. Every injector was tested for both slope flow value and latency value, and this graph helps to illustrate how much injectors can vary from one another with only OEM matching, or even with basic matching. Fuel Injector Clinic precisely matches each set using custom flow benches to offer consistent quality.

It all starts with high quality, reliable injectors which are then precisely matched on our custom flow benches. We include a Data Match Technology data sheet with each of our injector sets, which provides the most comprehensive data sheet specific to each individual injector set in the industry. We also provide OE specific data for Ford and GM ECU’s and are always building our database to include more applications.

FIC can also offer short pulse adder tables for those using newer, more advanced ECUs that are able to utilize this information. The data we provide helps make tuning simple and straightforward with no guessing.

What do you need to know in order to choose the best injector for your application?

JVH: To get an idea of which injector will be the best solution for a customer, we typically ask what their power goals are, what type of fuel, and what base fuel pressure they will be using. Each of these have an effect on fuel requirements. We also like to get an idea on how the vehicle is used; as a daily driver, dedicated race car, or somewhere in between.

Fuel Injector Clinic maps the performance of all its injectors to prove their performance. “You need to match these injectors very well, that’s where data-match technology comes in. It’s a way we have to measure the injectors not only by their flow rate, but also by the ‘dead-time,’ or latency, which is the delay of the injector opening.” says Jens Van Holten.

To help with this selection, we have an injector size calculator located on our website. By entering some basic information like engine aspiration, fuel pressure, and power goals, this tool can help builders hone in on what size injectors they’ll need to meet those output targets.

What do you need to know in order to run E85?

Using E85

Since E85 absorbs water, it requires more maintenance than typical fuels. Corrosion can lead to clogs, which in turn will affect the injector spray pattern and pressure. This can largely be addressed by running a tank of gasoline through the system occasionally. Racers should also be aware that not all E85 is the same, as the mixtures can vary depending on season and regional mixture requirements. If you plan to fill up at the pump, where the exact mixture may be unknown, Fuel Injector Clinic recommends installing a system that utilizes a flex-fuel sensor.

JVH: Since E85 uses about 27 percent more fuel than gasoline by volume for the same horsepower, it’s easy to run out of injector on a high power E85 setup. The way the performance world is going, it’s possible to run out of injector even using our largest E85 injectors, like the FIC 1650cc/min or the FIC 2150cc/min. It’s not uncommon anymore for a four-cylinder to need eight injectors to make the power demanded. Fortunately, there are a variety of standalone ECUs that can control two sets of injectors to meet the demands of those looking to make extremely high horsepower, but for the street, E85 is still the “poor man’s race gas!”

E85 requires more maintenance than normal pump gas since it is hygroscopic and therefore absorbs water, which leads to corrosion and clogging filters, so you need to take special care of the whole fuel system.

Black goo build-up on the injector tips caused by deposits due to different electronic charges in the E85 particles is another issue that needs maintenance, as it can have an effect on the spray pattern of the injector over time. Running a tank of gasoline every once in a while will take care for that problem.

While the pump may say E85, the mix varies significantly due to seasonal implications, which can be a real issue for racers who tune for a set fuel mix. This is why many high-end race cars either mix their own E85 or buy race E85. If you want to fill up at the pump, install a system that uses a flex-fuel sensor!

Finding the correct filter for E85 application can be tough. There are not that many filters out that are compatible with E85 and are also able to filter out small enough particles to keep the injectors clean. A product like Fuelab’s 6 micron fiberglass element filter meets both of these requirements.

What are some of the biggest misunderstandings about fuel injection?

JVH: We still hear from some old school guys that fuel injection isn’t that much better than a carburetor, when, with a very few highly-specific application exceptions, properly mapped fuel injection allows for far better control, easier fueling adjustment (which is a huge plus for the race teams) and automated responses to data provided by on-vehicle sensors. Which carburetor can shut off the fuel to save a motor when the fuel pressure dropped because a pump failed?


While old habits die hard, the reality is that fuel injection is superior to carburetion in almost every application, whether it be for a daily-driven street car or a purpose-built race motor. The difference in the level of control and ease of adjustment is vast, and fuel injection systems also provide fail-safes that carbs cannot, the latter of which can mean the difference between a bad run and a blown motor.

Another is the notion that “all injectors are the same.” All we can say to that is … that if it were true, we wouldn’t be in business. Understanding the variation of dead time or latency, the way increased fuel pressure effects injector operation and fuel compatibility are just a few of the areas that we spend tons of time researching. This information allows us to provide accurate data and operating information to the tuners, providing good results time after time. Choose an injector from a reputable company, you won’t regret spending a little extra!

Hanging around form the ’90s is the myth that low-impedance injectors – also known as peak and hold injectors – are superior to high impedance or “saturated” injectors. The origin of this myth has to do with the driving signal applied to larger injectors needed for high-performance cars in the 1990s, making the injector react faster than the saturated counterpart.

Nowadays this low-impedance peak and hold system has been thoroughly eclipsed by the continued development of the high impedance injector (while nobody has improved or redesigned the low impedance injector) into the many high-flowing versions providing excellent short pulse width control on OE ECUs. Which, by the way, only provide saturated signals.

Are Fuel Injector Clinic injectors compatible with all fuels?

JVH: All high-quality modern injectors made for gasoline use (not including our 2,150cc injector) feature a stainless valve and are compatible for use with all common gasoline and alcohol-based fuels. This means they are safe for use with all types of pump gas, ethanol blends like E85 and E98, race fuels, and fuels that are oxygenated with MTBE.

adapter_colorThe 2150cc injector is a high-quality modern injector, but was originally designed for use with natural gas and is a great solution for most fuels, but is not compatible with the chemical additive MTBE. The 2,150cc injector is safe for use with pump and race gas as well as alcohol-based fuels, as long as they do not contain MTBE (common fuels that contain MTBE are Q16 and VP Import).

It’s also worth noting that alcohol-based fuels are hygroscopic – meaning they absorb water – which can lead to corrosion in injectors when not used regularly. Because of this we recommend either using your 2,150cc injectors regularly when running E85, pickling the injectors to clean and store them, or just switching to gasoline for storage.