Installation And Plumbing Of A Fuel Cell In A Nissan 240sx Chassis

So, you're thinking about installing a fuel cell in your Nissan 240SX? Or maybe you've already started and hit a snag? Don't worry, it's a common upgrade, especially for those chasing more performance on the track. While it offers benefits like improved fuel delivery and weight distribution, it's not a bolt-on affair. It involves some fabrication, careful plumbing, and attention to detail. This guide will walk you through common problems encountered during the installation and offer solutions to get you back on track.

Common Problems and Solutions for Fuel Cell Installation in a 240SX

1. Fuel Cell Sizing and Placement

Problem: Choosing the wrong size fuel cell or trying to cram it into a space that's simply not suitable.

Solution: Proper planning is key. Before you even order a fuel cell, measure the area where you intend to mount it. The trunk is the most common location, but consider how much space you want to sacrifice. Think about future modifications you might want to make as well. Will you need room for a roll cage, air suspension components, or a larger battery? A smaller cell might be appealing for weight savings, but consider your fuel consumption rate. For drift cars or road race cars, a larger capacity (10-15 gallons) is generally recommended. For weekend warriors or cars seeing limited track time, a smaller 5-8 gallon cell might suffice. Don't forget to factor in the fuel pump and surge tank (if using) when measuring.

Practical Tip: Create a cardboard template the size of your potential fuel cell and physically place it in the trunk. This will give you a realistic idea of the space it will occupy.

2. Fuel Cell Mounting and Safety

Problem: Improper mounting can lead to fuel leaks, damage to the fuel cell, and, in a worst-case scenario, a dangerous situation during a collision.

Solution: A robust and secure mounting system is crucial. Most fuel cells are designed to be mounted within a metal cage or enclosure. Use this enclosure and mount it securely to the chassis using bolts and backing plates. Avoid simply welding the fuel cell directly to the car – the heat can damage the fuel cell material. The mounting points should be reinforced to withstand significant impact forces. If you're fabricating your own cage, use thick-walled steel tubing and ensure it's properly welded. Consider adding a fuel cell bladder for added safety. While more expensive, bladders are far more resistant to punctures and tears than the fuel cell container itself. Also, make sure your mounting allows for some expansion and contraction of the fuel cell due to temperature changes.

Practical Tip: Use fuel cell mounting straps in conjunction with your cage for added security. These straps are designed to hold the fuel cell firmly in place while allowing for some movement.

Approximate Cost: A pre-fabricated fuel cell cage can range from $200 to $500, depending on the size and material. Fabrication costs for a custom cage can vary widely but expect to pay at least $500 - $1000 depending on the complexity.

3. Fuel Line Plumbing

Problem: Incorrect fuel line sizing, incompatible materials, and leaky fittings can lead to fuel starvation, poor performance, and dangerous fuel leaks.

Solution: Use the correct fuel line size for your application. Generally, -6 AN (3/8") fuel lines are sufficient for most 240SX setups, but high-horsepower applications may require -8 AN (1/2") lines. Always use fuel-rated hose. Don't even think about using standard rubber hose – it will deteriorate quickly and leak. Braided stainless steel fuel lines with Teflon liners are the most durable and fuel-resistant option. Pay close attention to the compatibility of your fittings. Use AN fittings specifically designed for fuel applications. Avoid using pipe thread fittings – they are prone to leaks. Ensure all fittings are properly tightened, but avoid overtightening. Overtightening can damage the fittings and cause them to leak. Consider using a fuel filter before the fuel pump to protect it from debris in the fuel cell. Use a fuel pressure regulator and gauge to ensure proper fuel pressure at the fuel rail.

Practical Tip: Use a fuel line cutter to ensure clean, burr-free cuts. This will prevent leaks and ensure proper sealing of the fittings.

Tools Needed: Fuel line cutter, AN wrench set, Teflon tape or thread sealant (fuel-rated), safety glasses.

4. Fuel Pump Selection and Installation

Problem: Choosing an inadequate fuel pump or improper installation can lead to fuel starvation, especially under high-demand conditions.

Solution: Select a fuel pump that can provide sufficient fuel flow for your engine's horsepower. There are numerous online calculators that can help you determine the required fuel flow. Consider using an in-tank fuel pump or an external fuel pump with a surge tank. In-tank pumps are generally quieter and less prone to vapor lock, but external pumps can provide higher flow rates. If using an external pump, mount it as close to the fuel cell as possible and below the fuel level to ensure it's always primed. A surge tank is highly recommended, especially for drift cars or road race cars, as it prevents fuel starvation during hard cornering. Wire the fuel pump directly to the battery with a relay and fuse. Avoid using the factory fuel pump wiring, as it may not be sufficient for the higher current draw of aftermarket fuel pumps. Make sure your fuel pump's voltage supply isn't dropping too low when the pump is running.

Practical Tip: Consider using a Walbro 255lph fuel pump or AEM 320lph pump as a starting point. These are popular and reliable options for many 240SX builds. For higher horsepower applications, consider something from Aeromotive or Fuelab.

Approximate Cost: Fuel pumps range from $100 to $500, depending on the flow rate and brand. Surge tanks can cost between $150 and $400.

5. Venting and Fuel Fumes

Problem: Inadequate venting can cause pressure buildup in the fuel cell, leading to fuel leaks and potentially dangerous fuel fumes inside the car.

Solution: A proper venting system is essential. Most fuel cells have a vent fitting. Connect this fitting to a vent line that runs to a safe location outside the car. Never vent the fuel cell directly into the passenger compartment. Use a roll-over valve or a fuel cell vent filter to prevent fuel spillage in case of an accident. Consider using a charcoal canister to absorb fuel fumes and prevent them from being released into the atmosphere. Inspect your fuel system regularly for leaks. Pay particular attention to the fuel lines, fittings, and fuel cell seams. A fuel leak detector can be a useful tool for identifying small leaks.

Practical Tip: Route the vent line away from exhaust components to prevent the fumes from igniting.

6. Grounding

Problem: Poor grounding can cause electrical interference and potentially damage the fuel pump.

Solution: Ensure the fuel cell, fuel pump, and surge tank (if used) are properly grounded to the chassis. Use a thick gauge wire and connect it to a clean, unpainted metal surface. A dedicated ground wire running directly to the negative terminal of the battery is recommended.

7. Dealing with the Fuel Level Sensor

Problem: Getting the fuel level sensor to work correctly with the factory gauge.

Solution: This is a common challenge. Many aftermarket fuel cells don't have a fuel level sensor that is directly compatible with the 240SX's gauge. You have a few options. The simplest is to live without a fuel gauge. This requires diligently tracking mileage. The second, and more involved, option is to adapt the factory fuel level sending unit. This involves carefully removing the sending unit from the stock fuel tank and modifying it to fit inside the fuel cell. This may require some fabrication and experimentation. The third option is to purchase an aftermarket fuel level sending unit that is compatible with the 240SX's gauge. These are available from some performance parts suppliers. You'll need to research the impedance range of the factory gauge and find a sending unit that matches.

8. Legal and Safety Considerations

Problem: Ignoring local laws and regulations regarding fuel cell installation.

Solution: Before starting the installation, research your local laws and regulations regarding fuel cell installation. Some jurisdictions may require a specific type of fuel cell or mounting system. Ensure your installation meets all applicable safety standards. A well-installed fuel cell can significantly enhance the performance and safety of your 240SX. However, it's crucial to approach the project with careful planning, attention to detail, and a commitment to safety. If you're not comfortable with any aspect of the installation, it's best to seek the help of a qualified mechanic.