An Introduction to Fuel Cells and Certification

Radium Engineering offers top of the line fuel delivery solutions for the motorsports market, including fuel cells. Many consider fuel cells as a simple metal container, when in fact a proper motorsports fuel cell is more complex. A basic aluminum, stainless, or mild steel container is more susceptible to fracturing in the event of a collision. This would create leak(s) and could lead to a dangerous fire situation. Even a minor fender bender or the flexing of the chassis during hard driving could create enough force to distort and crack the metal container. Fuel weighs nearly 7 lbs per gallon. With a 15 gallon fuel cell that is 100 lbs of fuel sloshing, flexing the walls, and applying strain to the welds. When that much weight is subject to g-loading, the resulting forces are very large and can damage a poorly designed metal container. Furthermore, the thermal expansion created by elevated fuel, exhaust, and ambient temperatures put excessive stress on the can. Lastly, chemical compatibility, weld quality, and corrosion are concerns when using a metal container for fuel storage. In short, Radium Engineering does not recommend these types of fuel containers on performance vehicles.

Fuel cells used in motorsport racing often require FiA or SFI certification to ensure safety requirements are met. The guide below helps explain how a fuel cell works and why certification is necessary.

What is a Fuel Cell?
As shown, competition-grade fuel cells are generally comprised of three components: the outer shell (enclosure or can), the bladder (where fuel resides) and the foam baffling.
Radium Engineering fuel cell enclosures are made from lightweight aluminum, but other brands may use steel or other materials. The enclosure is the first part of the fuel cell to absorb damage and help prevent a catastrophe. This layer is similar to the construction of a helmet. The outer enclosure aids in safety but is not the most critical part. FIA and SFI specifications do not cover the outer can material alloy or thickness, only the internal bladder. Other governing bodies require a certain outer can thickness. For instance, SCCA requires a fully enveloped enclosure comprised of 0.036” steel or 0.059” aluminum.
The fuel cell bladder contains the fuel and protects from spills. The bladder must be resilient against impacts, punctures, and tears. The material also needs to be flexible enough to prevent cracking or fuel leakage in the case of impact and thermal expansion. These requirements have led to the development of different high-tech bladder materials used in the industry. Radium Engineering chose to only focus on molded polymer bladders as they have the best chemical compatibility and still meet all the structural testing requirements put forth by SFI and FiA.

The foam baffling is essentially a large open-cell sponge inside the fuel cell and serves several purposes. If catastrophic failure were to happen, this porous foam helps absorb the fuel and prevent an explosion. It also suppresses explosion potential by preventing fuel vapor buildup inside the cell. As an added benefit, it helps prevent fuel slosh which can cause fuel starvation. Fuel cell foam is a wear part and should be inspected periodically to ensure integrity. Loss of elasticity or degradation of any kind are signs the foam should be replaced.

What is FiA?
The Federation Internationale de l’Automobile (FiA) has been around for over a century. It is an international organization that promotes road safety around the world and creates rules and regulation governing all forms of motorsports. FIA's most prominent role is licensing and sanctioning of Formula One, World Endurance Championship, World Rally Championship and various forms of sports car and touring car racing.
For the safety of the driver, FiA homologation (certification) is required in many forms of racing. This covers many safety related components including fuel cell bladders. FiA has a few distinct classifications regarding fuel bladders: FT3, FT3.5, and FT5. There are other standards required by other sanctioning bodies, but FiA is the gold standard.
All of the ratings clearly define the requirements for materials, construction, and testing. The only difference between the ratings is the strength of the bladder material. All tests utilize the same procedures but the levels of certification are based on test results. FT3 is the first level requiring the lowest minimums while FT5 requires the highest. For example, Formula-1 requires FT5, but SCCA requires FT3 (although FT3.5 and FT5 are also acceptable.) Check with your sanctioning body to see what requirements your vehicle must meet.

What is SFI?
The SFI Foundation, Inc. (SFI) is a non-profit organization established to issue and administer standards for the quality assurance of specialty performance and racing equipment. The SFI Foundation has served the automotive aftermarket and the motorsports industry since 1978. Their service to the industry is a system of developing and administering various standards, certifications and testing criteria for use in motorsports.

Like FiA, SFI has a few different specification levels. SFI Spec 28.1 is the lowet and is for polymer foam-filled fuel cells. SFI Spec 28.2 is for crash resistant fuel cells and SFI Spec 28.3 is for competition fuel cells. Radium Engineering RA-Series fuel cells are certified SFI Spec 28.3.

Testing and Quality Control
Both SFI and FiA evaluate the bladder's structural integrity and perform rigorous mechanical testing including: tear, puncture, tensile, and compression.

Radium Engineering takes this process one step further. Before they leave our facility, every individual bladder is quality control tested as shown above.

Fuel cell certification expires 5 years after the date of manufacture. Check the label on the fuel cell bladder for the expiration date.

Heat, UV light, vibrations, and fuel are all factors that contribute to elastomers breaking down in a bladder. Water and alcohol fuels also can cause deterioration. Fortunately, all Radium Engineering bladders are made from a special polymer that are not as susceptible to chemical deterioration like coated fabric bladder variations (shown below) that are glued together.

However, all fuel cell bladders should be regularly inspected and replaced as needed.

Fuel cells generally require some level of maintenance. Regular maintenance ensures the fuel cell will last the full 5 years or longer in non-certified applications.
Maintenance tips: The fuel cell should be drained whenever the vehicle is stored for a long period of time. This will extend the life of the fuel cell. Alcohol is most damaging to the foam. Proper care of this part of the cell is crucial for maintenance. Foam breaks down over time and particles can clog the fuel system so it is imperative to use pre pump filtration. It is ideal to periodically replace the foam in the cell to increase cell longevity. Always follow the guidelines included with every Radium Engineering fuel cell.
Inspection: While replacing the foam, always inspect the bladder for any signs of wear, damage or degradation.

To conclude, metal box style "fuel cells" are prevalant on the discount market, however, they offer little to no engineering in regard to safety. The added cost of a certified bladder-style fuel cell can be easily justified in the event of a collision or other disaster.

Testing the ID Brushless Pump
NOTE: Radium Engineering is not a dealer of Injector Dynamics parts. Contact Injector Dynamics for more details about this pump system.

Electric motors continue to evolve and become increasingly more efficient. A significant improvement comes from brushless motor design which operates in a different manner than a standard DC brushed motor. For more details on how brushless motors work, CLICK HERE.
It is not uncommon to find OEM fuel pumps in modern high performance vehicle using brushless technology. They inherently draw less current (less heat) without sacrificing flow. But unlike traditional brushed variations, these pumps require a complex fuel controller to operate.

Dating back to 2013, Radium has embraced brushless pump technology. Fuel surge tanks utilizing both OEM brushless pumps (above) and aftermarket (below) have been available for several years. These have had limited interest due to the lack of affordable high-quality brushless controllers on the market. That is quickly changing.

For some time, the aftermarket company Injector Dynamics has been developing a state-of-the-art fuel controller for OEM brushless pumps from Bosch and Ti Automotive, shown below. 

The same Ti Automotive E5LM pump (found in the Bugatti Veyron) proved to have most potential. In it's most primitive state using the simple Ti Automotive BKS1000 controller, we've tested the E5LM pump at 13.5V to flow 590LPH at 43.5psi. See the tech article HERE.

We recently received a beta unit (above) from Injector Dynamics for testing. What you see is a high quality anodized aluminum control unit, Ti Automotive E5LM pump, stainless steel hardware, wire leads and associated components.

The fuel controller has 2 large cooling fans as well as diagnostic LEDs and a reset button for troubleshooting up to 11 error codes.

The Injector Dynamics BPC1100 system is RPM based and can run the pump at constant speed, MAP based speed, or PWM based speed using adjustable potentiometers (shown above). It is CAN equipped and has a pump speed output for ECU data logging. 

As expected, the controller is larger than others (Dim: 236mm x 160mm x 72mm). For a comparison, the Ti Automotive BKS1000 brushless controller is shown in the left foreground above.

To match all the features and capabilities of this unit, proper electrical is critical. It is mandated that a 125A fuse is used with 2AWG wire for the main power and ground connections. Shown above is an example of the minimum wiring to connect the ID BPC1100 to a Nissan R35 GT-R.

The Radium Engineering flow bench was set up using a MPR to regulate fuel pressure. The fluid used in the test has a specific gravity of 0.77 and flowed through a 6u Microglass Fuel Filter. Shown below are actual recorded numbers from the test bench instruments.

The graph above illustrates current draw at full output and various pressures with a 13.54V input. In extreme situations (8V input and 130psi @ 1100LPH) the current draw can get up to 95A. But don't forget, it's doing more than 5 times the work load as compared to a normal controller in those conditions.

As depicted above, current draw is only 5.5A in typical conditions (400LPH, 3BAR, 13.5V). 

The graph shown above is NOT a misprint. This system can flow over 1100LPH at ANY pressure up to 150psi.

With all of its features and potential, this system from Injector Dynamics is very impressive. At maximum settings, the pump could easily output over 1100lph.

It's unique in that the controller will always hit the target flow, even when conditions like fuel pressure and voltage vary. The only difference you'll notice is the current draw required to make it happen will change. When you compare this system to many others, it doesn't seem possible. This system gives the user the ability to specify their flow rate at any pressure, something not possible with a brushed fuel pump.

We predict that this system could replace the need for mechanical fuel pumps and could even take the place of multiple brushed pump setups as the norm. At this time, we are unsure when it will be available or how much it will cost. But, expect to get what you paid for.

Furthermore, this system can be used in many current Radium Engineering products. As long as the description states "...Ti Automotive E5LM...", the BPC1100 brushless system is compatible.
For more information on pricing and availability, please contact Injector Dynamics.


Refueling options from Radium Engineering
Radium Engineering has been hard at work developing products to make fuel cell filling easier and faster. These new parts work seamlessly with the Radium Fuel Cell Surge Tank (FCST) and associated fuel cells, which have proven to be a popular fuel delivery solution for performance vehicles.

In the past, it was left up to the installer to design and fabricate a custom remote filling solution for the Radium FCST, often requiring additional parts from other companies and making something work. This new product line means the installers can purchase all parts from Radium Engineering and know everything is going work perfectly together.

Because vehicles have different priorities when it comes to refueling, Radium has released several solutions to suit most needs. With so many new products to choose from, Radium has developed this simple explanation to help select the correct products for the customer. By answering a few questions, the customer can be assured they are getting the parts they need.

Understanding Terminology
Filling of the fuel cell can be done one of two ways; "direct fill" or "remote fill". The terms "direct" and "remote" are used often when describing Radium Engineering fuel fill products. Direct fill uses a screw-off cap to pour fuel directly into the cell, while remote filling refers to a body-mounted fill point connected to the fuel cell fill neck with a large diameter hose.
                                                                                        Direct Fill Example
Example of Direct Fill                                                                                         Remote Fill Example
Example of Remote Fill"Standard fill" or "dry break" refer to how the fuel is delivered to the fuel tank from the dump can (or fuel jug). Dry-breaks are handy when refueling needs to be completed quickly in a competitive environment. No caps need to be unscrewed, and fuel is forced into the tank with gravitational pressure. In the past, standard fill options were convenient due to compatibility with common fuel jugs and gas station nozzles. However, the Radium dry-break filler's female dry-break receptacle can be unscrewed. This allows filling with a standard gas station nozzle or non dry-break spout. This is a unique feature to Radium dry-breaks.

Radium Engineering standard remote mount filler using a fuel jug (shown below).

Radium Engineering standard remote mount filler (p/n 20-0505-V) can be used with a standard gas station pump nozzle (shown below).

Radium's dry-break fuel fill connectors, shown below, are an excellent choice when refueling needs to be completed quickly. These require special dump cans and fuel cell vents which can evacuate air quickly during the filling process.

Fuel Fill Product Lineup

Radium has assembled 4 "Complete Fuel Cell Refueling Kits" as detailed below. These comprehensive kits include all parts needed to make a complete filling and venting system that works as designed. The quick fill systems will fill at a rate of approximately 20 gallons per minute using the supplied high-flow venting accessories.

The product page for these complete fuel cell filling kits can be FOUND HERE.
The complete kits include everything needed, including a dump can and vent line, to handle the refueling and venting of a fuel cell equipped with a Radium FCST. 

Other Options
If a complete kit is not an ideal solution, then a custom filling system can be constructed using the products shown below.

A fuel neck bolts directly to the top of the Radium FCST via the 6-bolt hole pattern. Several different fill necks are available for direct and remote fill applications.
All direct mount fill necks can be FOUND HERE.
All remote fill necks can be FOUND HERE.

For remote fill applications, Radium offers the two remote (body) mounted fill points shown below, one for quick-fill dry breaks and one for standard filling. Each are designed to be used with a 1.5" ID fill hose. These products can be FOUND HERE.
The two options below share the same outer "shell", meaning that the dry-break recepticle in 20-0504-V can be unscrewed and replaced with the flush-mount cap from 20-0505-V, or vise-versa. This modular design is unique to Radium products and provides flexibility in what fill method can be used.

These remote fill points feature a very small pressure equalization hole for venting the fuel cell when the main vent may be closed, such as after quick filling. These small holes have a ball that will plug them in the event of a roll-over.

Proper venting is an important part of fuel cell refueling. Fuel can only get in as fast as air can get out. Large high-flow vents are needed for quick filling. A Dynamic Safety Vent (DSV) valve not only offers venting of the fuel cell, it closes the vent in case of rollover, preventing fuel loss. The Radium internal high-flow DSV (P/N: 20-0535) features a floating ball that closes the vent when fuel level reaches a certain calculated point, stopping fuel flow into the cell. This prevents over-pressurizing of the cell during gravity-powered quick filling.
An external vent such as 20-0462 will not automatically shut off fuel flow at a calculated point and is more suited for systems needing a high-flow vent, but without the aut-shut-off control.

NOTE: Radium increased the vent port size on the FCST December 2018 to make it compatible with quick filling. For older 20-014X-XX FCST units that want to use quick filling, an additional vent needs to be added. See part number 20-0439 below. The vent kits are a convenient solution for plumbing a vent line from the fuel cell vent port to outside the vehicle.
Dynamic Safety Vent valves can be FOUND HERE.
Vent Kits can be FOUND HERE.

The accessories below can be useful when putting together a custom system, or when replacement parts are needed. They can be found on various product pagesHERE.

Please contact for assistance with selecting products.

New Product Release: Subaru AOS and Oil Catch Cans
It is well known that Subaru engines are prone to excessive blow-by, creating a collection of oil and other contaminants in the intake system and intercooler. Do you ever see blue smoke in the rear view mirror? This is typically the contaminants getting burned through the combustion process. 

Shown above is a Subaru valve cover vent crossover pipe that is almost completely clogged with oil residue and carbon build-up.

Radium Engineering Solutions

1. Dual Catch Can Kit
For street driven or lightly modified vehicles, a simple oil catch can system will often do the trick. Radium Engineering has utilized its compact catch cans to created an integrated package for installation into various 2002-2014 Subaru engine bays. The catch cans are designed to collect and retain the oil and other contaminants, preventing them from being cycled back through the engine's air intake and intercooler system.
                                              CLICK HERE to learn more about the Radium Engineering catch cans.

The Subaru Dual Catch Can kit mounts on the RH stut tower and includes two catch cans. The forward catch can is plumbed in-line with the valve cover crankcase vents. This catch can filters and cleans the gasses before they are drawn into the intake pipe. It is responsible for keeping blow-by oil and other pollutants out of the turbo inlet pipe, turbocharger, and intercooler during high engine loads. The rear catch can intercepts the vacuum hose between the intake manifold and PCV valve. This catch can keeps oil and sludge out of the intake manifold. It functions when the engine is in vacuum and the PCV valve is open. The PCV system dynamically changes depending on the throttle body position. See below:

As shown above, when the throttle is closed, the one-way PCV "check" valve opens.

When the throttle is open, the PCV valve closes and all the crank venting is happening through the valve cover vents. The air being sucked in by the turbocharger helps create negative pressure in the intake pipe, which then results in a mild vacuum to the crankcase vent catch can, to help draw out the gasses. In all engine load scenarios, the PCV system promotes negative pressure in the crankcase that can extend engine life.

With the kit mounted in the area of the turbocharger, protection from heat is accomplished with a modular heat shield (shown above). This is necessary to keep the temperature of the catch cans down and help promote condensation of water vapor inside the catch cans where it is collected along with oil and unburnt fuel. The catch cans should be periodically checked using the dipsticks and drained as needed. To dispose the fluid, simply remove the 4 heat shield mounting bolts with a 3mm Allen wrench. The lower half of the catch can bodies unscrew for easy servicing. Always properly dispose of the contaminants. Do not pour catch can contents back into the engine oil.

Click here for the Subaru Dual Catch Can Kit product page

2. Air Oil Separator (AOS) Kit
With a higher engine power output comes an increase in oil circulating through the crankcase ventilation system. Horizontally opposed engines, in particular, expel an excessive amount of oil through the ventilation system. In extreme cases, this may overwhelm the capacity of the standard sized catch cans during long track sessions. Instead of using a large reservoir to retain all the collected contaminants, the oil can be returned to the pan. However, this process must take into account several considerations in order to function properly. 

Shown above is the Radium Engineering Air Oil Separator (AOS). The AOS is built on the foundation of the Radium Competition Catch Can, but with a new specifically designed bottom plate. Full CNC construction, sealed with O-rings and anodized. The AOS still features all of the same oil baffling media found in the competition catch cans. However, instead of collecting oil, the AOS drains back to the engine through the large baffled -10AN ORB bottom port, shown above.

The bottom plate not only features a large oil return port, it also functions as a heater to prevent water from condensing inside the can. The heater is fed by coolant circulating to/from the engine. The cooling fins, shown above, increase the effective surface area of the heating element. Also, if any water were to make it's way into the canister, it would be trapped underneath the lower density oil in the bottom trench. The center port baffle provides a layer of protection to keep debris from enterning the crankcase. 

For AOS crankcase plumbing, the valve cover vents are routed into the top inlet where the stainless steel condensing material separates the oil from the gasses. The PCV valve is removed and the system is no longer hooked up to the intake manifold (vacuum). The crankcase port in the center of the block (green arrows) is now routed directly to the AOS bottom port with a large diameter -12AN (3/4" ID) hose. The filtered liquid oil is collected at the bottom of the AOS and is drawn into the oil pan through the 3/4" hose. Meanwhile, the clean crankcase air can either be vented to atmosphere (VTA) or recirculated to the turbo air inlet pipe (see instructions for details) out of the side port of the AOS.

The AOS completely disassembles for easy servicing when needed, as shown above. 

Because of limited vertical clearance, special low-profile banjo style fittings were developed for the Subaru AOS kit. These fittings are super compact, yet high flowing. They are machined from aluminum and anodized.

Radium installation kits include all necessary parts for an easy bolt-in process.

Shown above is the AOS system fully assembled with a Subaru specific mounting bracket and fittings.

When installed, the valve cover vent lines "Y" together and are plumbed into the top port of the AOS can. The side port is used as the vent to atmosphere (VTA), or it can be routed to the turbo inlet pipe for a closed system. The bottom port of the AOS can is plumbed with a 3/4" hose to the crankcase vent port on top of the block. This line acts as a way for crankcase gasses to enter the AOS, but also functions as the path for oil to return back to the oil pan.
Click here for the Subaru AOS Kit product page

Both Dual Catch Can and AOS kits are available for the Subaru WRX, WRX STi and Forester XT in the 2002-2014 model year range.

Contact with any questions.

New Products for the 2015+ Subaru WRX
Radium Engineering has just released a range of products for the 2015+ Subaru WRX with the FA20 engine. These products are designed to improve the driveability and performance of the WRX without sacrificing reliability. 
The WRX version of the FA20 engine is equipped with tumble generator valves to assist with emissions during cold engine temperatures. These devices also impede air flow in the intake manifold runners. By eliminating the obstruction, a clear airflow path is established. The Radium Engineering TGV deletes are machined from 6061 aluminum and anodized green or black. Installation is quick and easy (compared to EJ-series engines) and can be performed in about 30 minutes.

The tumble generator valves are an emissions control device, and as such should be removed only for vehicle operating off-highway. It is also recommended that a complimentary engine management tune be implemented to take full advantage of the TGV deletes. No permanent modifications to the vehicle are necessary to install the TGV delete kit.

Even with low mileage modern cars, oil accumulation in the air intake stream can happen. The Subaru FA20 engine places the turbocharger down low, in front of the engine. This leads to oil from the PCV system collecting in the turbo air inlet pipe, down near the turbocharger. This oil is result of blow by coming through the crankcase ventilation system. This oil will eventually be digested by the turbocharger and deposited through the charge piping and can even result in blue smoke from the tailpipe. 

The Radium Engineering Dual Catch Can Kit intercepts the PCV gasses and traps the oil and other pollutants before they can make it back into the intake stream. The kit tucks in perfectly on the RH side of the engine bay next to the ABS module, mounts to existing engine bay fasteners and requiring no relocating of engine bay components. The front catch can intercepts the crank case vent hose that connects to the turbo inlet pipe, keeping oil out of the turbo inlet. The rear catch can intercepts the PCV hose coming off the block and going to the intake manifold, keeping oil out of the intake manifold. The catch cans are designed to withstand boost pressure and are sealed, so direct connection to the intake manifold, even with forced induction, is OK.
This kit is perfect for a street driven car experiencing mild amounts of blow-by.

For more race-centered applications, or cars with built high-powered engines, more oil blow by is usually experienced, often overwhelming the volume of the standard Radium catch cans.  For these applications Radium Engineering applied it's Air/Oil separator to the FA20 engine.

The Air/Oil Separator functions in a similar manner to the catch cans, however, the big difference is that oil is returned back to the engine, rather than stored in the catch can. But catch cans do not only catch oil, they also catch water condensation and it is not ideal to have this water mix with the oil, then return it to the engine. To remedy this, the Radium AOS is heated with engine coolant. This keeps the water vapor from condensing and mixing with the oil.

Engine coolant is plumbed through the bottom plate of the AOS.

Another important aspect of the AOS is that it does away with the function of the PCV valve. Instead, the engine is allowed to breathe freely from both the crank case vent port (at the front of the engine) and the PCV valve port (under intake manifold). The PCV valve is removed from the engine block and replaced with Radium's custom made PCV delete fitting, shown below.

This fitting screws into the block and adapts to a -10AN male. It is straight through, with no check valve or any other device built in. This allows maximum ventilation to the AOS through this port. This is also the path for collected oil to drain back to the engine block.
With both engine ports breathing freely into the AOS, the AOS needs to be vented to atmospheric pressure. This is done by routing the AOS side port back to the turbo inlet pipe. This creates a closed-loop system.
The AOS was designed to mount in the engine bay near the brake master cylinder (for LHD vehicles only) using the Radium Master Cylinder Brace for the 2015+ WRX as the mounting point.

The master cylinder brace is a simple and effective way to reduce firewall flex resulting from brake pedal pressure.It is machined from 6061 aluminum and mounts to the strut tower using pre-existing threaded holes. Clearly visible in the photo below are the three threaded holes in the brace where the AOS bracket attaches.  The brace is sold as an individual item, or as part of the AOS kit.

While installing an AOS kit can be done with the stock fuel feed hose, Radium offers an aftermarket fuel feed hose replacement that cleans up the fuel routing and offers better clearance with the AOS. The hose has a PTFE core that is compatible with all fuel types and also features machine-crimped end fittings.

For all of the products shown here, and a few more, please click HERE.
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