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Tech Review: AFIS High Performance Fuel Injectors

Posted By: Steve Baur
Advanced Fuel & Ignition Systems recently released an all-new line of high-flow fuel injectors designed for high-performance race applications. Let’s take a deeper look into the new AFIS injectors to see what they are all about, and how AFIS ensures they deliver as advertised.
 
Advanced Fuel & Ignition Systems
 
Advance Fuel & Ignition Systems (AFIS) is a company that was started in 2012 by Harry Hruska, the founder of Precision Turbo & Engine and HPL Superior Lubricants. In addition to being an NMCA Xtreme Pro Mod competitor, Hruska is also a pioneer, developing multiple new products for the racing industry. While looking at the fuel injector market, he became troubled with the direction it was going. Having been deeply immersed in fuel injection since the late 1980s provided Hruska with 30-plus-years of experience testing, selling, and tuning fuel injection in just about every arena. Hruska realized that the fuel injector market had become skewed by companies advertising “high flow” injectors by simply raising the fuel pressure. Hruska felt this was not only a deceptive but an unsafe practice, he decided it was time to make a change.  
 
“The market needed a high-flow race injector that utilized the much safer SAE standard flow rating (43.5 PSI, 3 BAR),” Hruska told us. “We felt that rating an injector at high base pressure is not only unsafe, but deceptive or confusing to the end user. We need to get back to real numbers!”
 

One might ask why companies design their injectors around high base fuel pressures, and we posed that question to Hruska.
 
“High base pressures allow for greater flow from small injectors, making them look big when they are not. It's a game to get large flow numbers, much like taking an engine to the dyno shop that will publish the highest horsepower!” Hruska also noted that fuel injectors using a high base pressure make it virtually impossible to use an electric fuel pump due to the high fuel pressure requirements. “AFIS injectors utilize low base pressure, which allows for the use of electric fuel pump on many applications.” 
 
Injector ratings aside, Hruska also felt there were numerous improvements that could be made over existing injectors on the market.
 
“The high-flow injectors available at the time had a reputation for being unreliable or requiring frequent and costly service,” Hruska explained. “We wanted to change this by offering a safer, more traditional and reliable design, eliminating the need for frequent service. To take it a step further, we back the injectors by our Limited Lifetime Warranty. So, if there is ever an issue with an injector, we simply replace it at no charge.”
 

The next step was to engineer and test his own fuel injectors designs. Before this could be done, he and his team had to first design and build an injector flow bench capable of supporting the large fuel volume required to test the limitations of his design.
 

When measuring performance, the results are only as good as the test equipment. AFIS thought of everything when designing its fuel injector flow bench, including how different injector driver strategies might affect injector performance. In order to do this, AFIS designed its flow bench to easily switch between the multiple EFI systems and injector drivers already installed. The company also built a test rig to perform durability testing and push an injector to its limit.
 
“Designing our own flow bench was key to the success of the program. Injector flow benches capable of accurately measuring over 1000 LB/HR of flow are not commonly available. We designed and outfitted our flow bench with everything required to engineer, test, validate, and flow-match each and every injector we sell.”
 
To see the AFIS injector flow bench in action is intriguing, as it has the capability to measure every aspect of injector operation and how they perform with different EFI systems.
 
“We frequently use it to measure the functionality of the injectors with different coils, ball and seat configurations, voltages, materials, driver setting, etc.,” Hruska explained. “Another advantage to the flow bench is that we can overlay realtime current vs. the injector movement (open & close). This gives us an accurate picture of what the driver requirements are for each injector. We can also test the different injector drivers on the market in order to determine functionality and compatibility with AFIS injectors. This is critical for proper injector operation between different EFI systems/drivers.”
 

Hruska and his team also employ an oscilloscope as a vital part of the testing and engineering program.
 
“The oscilloscope allows us to measure not only the function of the injector with different coils, voltages and current settings, fuel pressure, etc., but it also allows us to validate different injector driver strategies.” Hruska also told us that they offer the flow bench services to anyone regardless of the brand of injectors. We actually had an opportunity to see the flow bench in action at the NMRA/NMCA Power Festival at US 131 Motorsports Park in Michigan, as Hruska helped a fellow racer by testing a competitor’s injector in order to help validate an issue they found in their datalogs.
 
AFIS High Performance Fuel Injectors
 
The latest line of fuel injectors that AFIS has brought to market are the company’s High-Flow units that are available in 250-, 400-, 600-, and 800-lb/hr flow rates measured at 43.5 psi (3 bar). AFIS engineered the stainless steel injectors to be able to be used with Methanol, Ethanol, Gasoline, and CNG applications, and Hruska also told us that they are working on Hydrogen applications for the future as well.
 
The AFIS High Flow Injectors feature 1-piece construction to provide OEM quality and reliability. They utilize an EV1-style connector and the low-impedance (Peak and Hold) coil. The injectors are also flow-matched for accurate fuel delivery across all cylinders.
 
One further benefit of the AFIS fuel injectors is that they offer linear operation to as high as 95 precent duty cycle. What does this mean to the end user?
 
“We can confidently operate the injector at duty cycles above 80 percent without worrying about the injectors going static. On my Pro Mod, the injectors have dramatically changed (almost eliminating) the fuel corrections, not to mention the idle quality with such big injectors. We have also found that lower base pressures equals less disruption of air speed when the fuel enters the air stream. More CFM equals more HP!”
 
“It’s almost impossible to tune a car with unpredictable injector behavior(s),” Hruska told us. “Many of the competitors injectors begin to go static around 80 percent duty cycle. This is also critically beneficial on an application where cylinder correction can exceed 15 percent, effectively causing some injectors to go static.”
 

Hruska has put his AFIS High Flow fuel injectors to work, not only on his test bench, but also in his own Pro Modified racing program. His C7 Corvette Pro Mod features a 526cid BAE HEMI with twin 94mm turbochargers and two sets of AFIS fuel injectors. 
 
“We use AFIS 400 lb/hr primary injectors and AFIS 600 lb/hr secondary injectors, which operate at a 50psi base fuel pressure,” Hruska noted. “We use a pair Holley external injector drivers with an FT600 ECU. We have the capability to flow over 8,000 lb/hr of fuel at 50 psi base fuel pressure, enough to easily support well over 4,500 HP on Methanol.”
 

Hruska is no stranger to the Pro Modified ranks, having campaigned several cars across as many series over the years.
 
“We believe in racing what we sell and the race program allows us to do just that,” Hruska said. “The race program has been key to the success of the injectors by allowing us to validate our results from the flow bench in a real-world application.”
 
If you’re looking for fuel injectors for your big horsepower application, check out what AFIS has to offer.

Source
 
Advanced Fuel & Ignition Systems
(219) 996-3460
https://www.hploil.com/afis

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