Fuel Pressure Fundamentals For Nitrous Users

Nitrous oxide systems are designed to use a combination of fuel and nitrous jets based on specific nitrous and fuel pressures. This is because reducing either fuel or nitrous pressure lowers total flow. Therefore, fuel pressure is critical. If you aren't monitoring and controlling the nitrous pressure accurately, performance at the track will be different on each pass, tuning will be difficult, and parts damage can occur.

Fuel pressure creep

One of the primary causes of fuel pressure creep is a faulty or worn-out fuel pressure regulator. Regulators are responsible for maintaining stable fuel pressure, and over time, their diaphragms can become old and stiff, leading to pressure creep issues. In some cases, the issue may lie with a weak spring or a damaged diaphragm, causing the regulator to require rebuilding or replacement.

To address fuel pressure creep, it is recommended to install a high-quality fuel pressure regulator, such as those offered by Aeromotive or Mallory. Additionally, converting from a deadhead system to a bypass system can help alleviate creep issues. It is also crucial to maintain the fuel system, including regular cleaning of the fuel filter and ensuring proper jet sizing and fuel pressure for nitrous applications.

When setting up a nitrous kit, it is essential to follow the manufacturer's instructions and recommendations. The jetting setup, fuel pressure, and timing adjustments are critical factors in ensuring the safe and effective use of nitrous oxide. Running nitrous without the correct fuel pressure can lead to engine damage or even destruction, as lean air-fuel mixtures can cause detonation and piston damage. Therefore, it is always advisable to err on the side of caution and seek advice from experienced individuals when in doubt.

Nitrous pressure consistency

Nitrous oxide, commonly referred to as N2O, is a powerful tool for boosting engine performance. It involves introducing a mixture of two parts nitrogen and one part oxygen into an engine's internal combustion process, resulting in greater cylinder fill and the potential for significant power gains. However, achieving consistent performance with nitrous oxide can be challenging due to the variables involved.

One key factor in maintaining nitrous pressure consistency is keeping the pressure within the calibrated range specified by the nitrous manufacturer. Typically, nitrous kits are designed to operate at bottle pressures between 950 and 1,050 psi. Deviating from this range can lead to either a lean or rich air/fuel mixture, impacting engine performance and potentially causing damage. As the level of nitrous in the bottle changes, so does the resulting bottle pressure, introducing variables that affect consistency.

To address this issue, some companies have developed bolt-on nitrous regulation systems that control both nitrous oxide density and bottle pressure. These systems use a high-pressure air or nitrogen cylinder connected to the nitrous bottle to maintain constant bottle pressure and ensure that all contents are expended, providing consistent performance and eliminating the need for a bottle heater.

Another critical aspect of nitrous pressure consistency is the length of the nitrous lines. Keeping these lines as short as possible is essential because engine temperatures can heat the lines and raise the nitrous temperature above its critical level before it exits the nozzle. This can cause the nitrous to expand and vaporize, reducing its density and affecting performance. Therefore, minimizing line length helps maintain nitrous density and consistency.

Additionally, the starting pressure of the nitrous system plays a role in consistency. Higher starting pressures result in a more significant and faster pressure drop during a run, making it challenging for the progressive controller to maintain optimal conditions. It also increases the load on the nitrous solenoid plunger and reduces nitrous density in the bottle. As a result, starting with lower pressures and jetting accordingly can help maintain consistency throughout the run.

In conclusion, achieving nitrous pressure consistency requires a combination of techniques, including maintaining calibrated bottle pressures, using regulation systems, minimizing line length, and optimizing starting pressures. By controlling these variables, racers can unlock the full potential of nitrous oxide while minimizing the risks associated with inconsistent performance.

Flowing fuel pressure

Fuel pressure plays a significant role in the performance of an engine, and it becomes even more crucial when using nitrous oxide. The fuel pressure must be adequately regulated to ensure the engine receives the necessary amount of fuel to support the additional power produced by the nitrous system. Insufficient fuel pressure can lead to a lean air-fuel mixture, resulting in engine damage. Therefore, it is essential to maintain the recommended fuel pressure specified by the nitrous kit manufacturer.

The jetting setup of a nitrous kit is designed to work with a specific fuel pressure. For example, some kits may require 10 PSI for carbureted systems and 45 PSI for fuel injection setups. Deviating from these recommended fuel pressures can lead to improper air-fuel ratios, affecting engine performance and potentially causing damage. It is crucial to follow the instructions provided with the kit to ensure the fuel pressure is set correctly.

When tuning the fuel pressure for nitrous, it is essential to consider the jet size being used. The jet size determines the amount of nitrous and fuel delivered to the engine, and the fuel pressure must be adjusted accordingly. A dedicated fuel pressure regulator for the nitrous supply is often recommended to fine-tune the pressure while flowing it into a bucket to ensure stable pressure. This setup allows for accurate testing and adjustments before final installation.

Additionally, it is important to note that fuel pressure alone does not guarantee adequate fuel delivery. The fuel volume and flow must also be considered. The fuel volume available at the pump inlet, delivery line capacity, pump's ability to supply sufficient volume, and system pressure all play a role in ensuring optimal fuel delivery. A restricted fuel filter, defective pressure regulator, or underperforming fuel pump can reduce fuel flow, leading to potential engine issues. Therefore, it is crucial to assess both fuel pressure and flow to ensure the engine receives the required amount of fuel, especially when using nitrous oxide.

In conclusion, achieving the correct flowing fuel pressure for nitrous applications requires careful consideration of multiple factors. Following the kit instructions, tuning the fuel pressure to the jet size, and ensuring sufficient fuel volume and flow are all critical steps to optimize performance and protect the engine. By understanding the relationship between fuel pressure, volume, and flow, enthusiasts can safely harness the power of nitrous oxide while maintaining the reliability of their vehicles.

Fuel pressure changes

Nitrous systems are designed to use a combination of fuel and nitrous jets based on specific nitrous and fuel pressures. This is because reducing either fuel or nitrous pressure lowers the total flow. The same jet size will flow more fuel or nitrous at a higher pressure. This is why fuel pressure is critical.

Closed-End Nitrous Fuel System

With a closed-end or dead-head nitrous fuel system, the fuel pump pushes fuel up against a closed valve when the fuel solenoid is not activated, increasing the line pressure and causing fuel pressure creep. Most fuel pumps have an internal bypass set to a given pressure, usually higher than the nitrous fuel system flowing pressure. When the nitrous system is activated and the fuel solenoid opens, the pressure drops significantly. This is why nitrous fuel pressure must be set by creating system fuel flow.

Fuel Pressure and Nitrous Performance

By not having the correct flowing fuel pressure, obtaining a good tune-up becomes impossible, leading to frustration when it comes to performance. Flowing the fuel pressure is a key to a proper tune-up and is also a tuning method. You have to flow fuel through the regulator to properly set it. You can't properly set a dead-headed regulator. Fuel pressure changes are a method to leaning or enriching your tune as needed based on plug reading and the incrementals on your time slip.

Fuel Pressure Tools

To properly use and tune a nitrous system, you need a fuel flow tool and an accurate nitrous pressure gauge in the car. The flow tool is used to flow fuel through the regulator to accurately set the fuel pressure and make changes. When it comes to nitrous pressure, a four-inch nitrous pressure gauge in the car is recommended. This way, regardless of the nitrous bottle used, it is always set to the same gauge.

Nitrous pressure gauges

The nitrous pressure gauge typically includes a pressure sensor that can be installed directly into your nitrous tanks or system. This sensor provides highly accurate readings, which are then displayed on the nitrous pressure gauge. By having this gauge installed, you can easily monitor your nitrous pressure levels and make adjustments as needed to ensure optimal performance and prevent engine damage.

GlowShift, for instance, offers a range of nitrous pressure gauges that provide readings from 0 to 1600 PSI. Their gauges come with a 1/8-27 NPT pressure sensor, as well as the necessary harnesses, mounting hardware, and installation instructions. The flexibility in installation allows you to choose the most convenient location for the gauge, whether it's on the A-pillar, dash, or console, providing effective monitoring without the need to connect directly to the bottle.

When it comes to fuel pressure for nitrous systems, the optimal pressure can vary. Some sources recommend a fuel pressure of around 10 PSI for low-pressure jetting, while others suggest that 4 to 7 PSI is sufficient. It's important to consult the instructions and requirements of your nitrous kit to determine the correct fuel pressure for your setup. Additionally, factors such as dome, compression, and nozzle can also influence the optimal fuel pressure.

Frequently asked questions