Nitrous Nozzles

I Tried 3 different dry Nitrous Nozzles, two of them are good for long distance before the throttle body and 1 is good for past the TB in the intake.  

Nitrous Jets

Distribution Block

Dry Direct Port kits Do exist!

Because a dry nitrous system does not inject fuel with the nitrous, it relies entirely on the engine's computer (ECU) tune or a Nitrous Controller to add the correct amount of fuel through the existing fuel injectors.

Zex Wet & Dry Notes!

Wet & Dry Nitrous Systems A fuel injected dry manifold system uses a spray nozzle to deliver only nitrous oxide to the intake. A wet manifold system introduces fuel and nitrous into the intake manifold. With a dry manifold system, the additional fuel is supplied by increasing fuel delivery from the injectors when the nitrous system is activated. It is called a dry manifold system because there isn't any fuel present in the intake manifold. The ZEX™ Nitrous System is a dry system.

Powerful Features, Plus it's Easy to Use and Easy to Install The ZEX Nitrous Oxide System automatically adjusts the amount of enrichment fuel in relation to the nitrous bottle pressure, thereby maintaining consistent nitrous to fuel ratios. 

Why Our Nitrous System Is Better? What makes our dry manifold nitrous system work so well is that the fuel control circuit references the actual bottle pressure to determine enrichment fuel needs 

How The ZEX Nitrous Oxide System Works The ZEX™ Nitrous oxide injection kit begins with a supply cylinder containing pressurized liquid nitrous oxide. This cylinder is connected by means of a delivery hose to a normally closed electric solenoid valve. This solenoid valve, which is attached to a manifold assembly, is engaged and disengaged via the TPS switch. The manifold assembly distributes the nitrous oxide to the engine's air inlet and the kit's supplemental fuel control circuit. The nitrous oxide that is delivered to the engine's air inlet is conveyed via a delivery hose to an injection nozzle. The amount of nitrous oxide, which provides the oxygen required for the horsepower increase, is adjustable by means of a metering jet installed in the injection nozzle itself. The nitrous oxide that is distributed to the fuel control circuit passes through a small bleed orifice. This bleed orifice provides a reference source of bottle pressure and a controllable source of pressure to perform the needed function of fuel enrichment. Fuel enrichment occurs by conveying this source of pressure through a delivery hose to the vacuum port on the fuel pressure regulator. This source of pressure on the rubber diaphragm of the fuel pressure regulator causes an increase in fuel pressure. This increase in fuel pressure performs the function of adding fuel volume through the engine's own injectors. The amount of additional fuel that is added can be changed by an adjustable metering jet in the fuel control circuit. This jet accomplishes the task by controlling the amount of pressure allowed to build in the delivery hose to the fuel pressure regulator. The jet bleeds off excess pressure in the fuel control circuit and vents it through a delivery tube, back to the intake manifold plenum. 

 https://static.summitracing.com/global/images/instructions/zex-82011.pdf 

Notes: on my single Jet dry shot 

For my setup, the Mass Air Flow (MAF) sensor is positioned less than 1 foot away, while the nozzle is only 7 inches from the throttle body. 

Do dry shot systems have distribution challenges. So why nitrous might not reach each port evenly:

1. Airflow Path & Intake Manifold Design

• Most intake manifolds are designed to distribute air and fuel mist, not pure nitrous oxide.

• When nitrous is injected as a gas into a plenum-style intake manifold, it may not mix evenly with the incoming air.

• Some cylinders may get more nitrous than others due to airflow turbulence, bends, and runner lengths, leading to uneven distribution.

2. Lack of a Carrier (Fuel) in the Mix

• In wet nitrous systems, fuel is injected along with nitrous, creating a heavier mist that follows intake airflow paths more predictably.

• In a dry system, nitrous is a gas and behaves differently than a liquid fuel-air mixture. It can pool in certain areas or take the path of least resistance, meaning some cylinders may get more nitrous than others.

3. Intake Manifold Runner Variability

• Some intake manifolds, especially long-runner or dual-plane designs, can cause nitrous to favor certain runners due to differences in air velocity and turbulence.

4. Airflow & Engine Demand Differences

• For my throttle half open.     Depending on RPM and throttle position, certain cylinders may naturally pull in more air than others, affecting how much nitrous each one receives.

• At low RPM, airflow is weaker, and nitrous might not fully mix before entering the runners.

How to Improve Dry Shot Distribution

• Proper nozzle placement – The ideal location depends on the intake design but should promote better mixing with incoming air.

• Higher intake velocity – Running the system at wide-open throttle (WOT) helps improve nitrous distribution by ensuring more turbulence in the intake.

• Aftermarket intake manifolds – Some intakes are better suited for nitrous use, particularly those with better flow balance across cylinders.

Why Direct Port or Wet Systems Solve This Issue

• Direct port nitrous eliminates the issue because each runner gets its own dedicated shot of nitrous.

• Wet nitrous systems mix nitrous with fuel at the injection point, improving mixture uniformity as it enters the runners.

A dry shot can work well on engines with strong fuel injection tuning and even intake airflow, but for high-horsepower or high-precision setups, direct port or wet nitrous is the better option.

Advantages of Direct Port Nitrous

1. Even Distribution – Direct port systems inject nitrous and fuel directly into each intake runner, ensuring that all cylinders receive an equal mixture. This prevents lean conditions in certain cylinders, which can lead to engine damage.

2. More Power Potential – Since each cylinder gets its own dedicated nozzle, you can precisely tune the nitrous and fuel delivery for maximum performance. This allows for significantly higher horsepower gains compared to a single fogger or plate system.

3. Reduced Risk of Fuel Pooling – In plate and single-fogger systems, fuel can sometimes pool in the intake manifold, leading to inconsistent combustion or even backfires. Direct port injection eliminates this risk.

4. More Efficient Combustion – By delivering nitrous and fuel right at the intake runners, direct port systems improve atomization and combustion efficiency, resulting in smoother and more reliable power delivery.

5. Ideal for High-Boost Applications – Turbocharged and supercharged engines benefit from direct port nitrous because it prevents distribution issues that arise from forced induction airflows.

Downsides of Direct Port Nitrous

• More Expensive – Requires more components (nozzles, jets, lines, distribution blocks) and is more complex to install.

• Labor Intensive Installation – Requires drilling and tapping intake runners, making it a more involved process than bolt-on plate or fogger systems.

If you're running a mild street setup or just looking for a basic power boost, a wet plate or single fogger system might be more practical. But for serious performance applications, direct port nitrous is the best choice.

OpenAI. (2025). ChatGPT  [Large language model]. 

can i run a dry shot of nitrous on director ports?

ChatGPT said:

Yes, you can run a dry shot of nitrous on direct port injection, but it requires some careful tuning and additional fuel compensation. Since a dry shot only introduces nitrous oxide without extra fuel, the ECU or fuel system must compensate for the additional oxygen to maintain a proper air-fuel ratio (AFR).

Considerations for a Dry Shot on Direct Port:

1. Fuel Compensation – You must ensure your injectors and fuel system can provide enough fuel when the nitrous is activated. This is typically done through ECU tuning or increasing fuel pressure.

2. Proper Nozzle Placement – Each cylinder must receive an equal amount of nitrous to avoid lean conditions and potential engine damage.

3. ECU Tuning – A standalone ECU or nitrous controller can adjust fuel delivery and timing when nitrous is engaged. Retarding timing is crucial to avoid detonation.

4. Intake Manifold Considerations – Some intake designs don’t distribute nitrous evenly, which can cause some cylinders to run leaner than others.

5. Safety Measures – Running a wideband O2 sensor and monitoring AFR is essential. A window switch and RPM activation also help prevent backfires and misfires.

While dry shots are typically easier to set up for single-port or throttle-body injection, direct port dry systems require advanced tuning and monitoring to prevent engine damage. If you're not experienced with nitrous setups, a wet direct port system may be safer and easier to manage.

If I do direct port, my goal is to make it more like the PRO Race Fogger Kits.

Stainless steal? Are they stronger? Stainless steal into an aluminum intake or aluminum into aluminum 

I read on allot of forms about using red locktite for sealer. Nitrous Outlet and NX express say to use it to. Also it . I will use blue loctite on the inlet.

Other kit exaples that offer a Dry Direct Shot

According to google :  AN4 threads are 1/4-28 UNF with a thread length of 0.469 inches, except for the AN4H-3A, which has a thread length of 0.406 inches. The size of an AN fitting is measured over the thread. If you don't have a measuring tool, you can use an open-end wrench to determine the size. For example, if a 7/16 inch wrench fits over the threads but a 3/8 inch wrench doesn't, then the fitting is a 4AN. 

AN3 bolts have a 10-32 thread and a 3/16 in shank diameter. All sizes of AN3 bolts have a thread length of 0.406 in, regardless of grip length. The grip size for AN3 bolts is 1/4 in, and the wrench size is 3/8 in. 

Size                 Wrench Size

-3AN         7/16 or 1/2

Film notes

Now this is a test in a open port environment, not a closed environment. Nitrous may behave differently with closed valves  being present, vacuum pressure and a large build up of Nitrous in the intake. This test shows you the less resistance pathways with Nitrous wants to go to.

The smallest jet sizes available for dry shot nitrous systems typically start around .014 (14 thousandths of an inch) to .018 inches.

• Some jet charts and manufacturers list jets as small as .014 or .016 for the lowest horsepower dry shots (often around 6-9 HP gain).

• For powersports/single-cylinder dry systems, jet packs are offered starting around .018 (for 10 HP).

To determine the correct dry nitrous jet size for each of your six nozzles to achieve a 100 HP shot, you first need to calculate the target horsepower per cylinder.

Calculation

1. Determine HP per Nozzle: Since you are using a 6-nozzle system, the total horsepower is divided evenly across the nozzles:
   $$\frac{100\ HP\ (Total)}{6\ Nozzles} \approx \mathbf{16.7\ HP\ per\ Nozzle}$$

2. Consult a Jetting Chart: Jet size is not a simple linear calculation; it's based on flow rate, which is specific to the manufacturer's nozzle design and system pressure. You must consult the jetting chart provided by the manufacturer of your dry nitrous kit (e.g., Nitrous Express, NOS, ZEX) for a 6-cylinder direct port or 6-nozzle system.

Estimated Jet Size

For a target of approximately 17 HP per nozzle in a direct port system, the required nitrous jet size typically falls in the range of:

$$\mathbf{.018} \text{ to } \mathbf{.022}$$

• Example from a common chart: Some manufacturers' charts show that a jet size in this range is appropriate for a low-to-moderate shot on a single cylinder.

Critical Warning for Dry Nitrous

Always use the jetting chart provided by your system's manufacturer.

Because a dry nitrous system does not inject fuel with the nitrous, it relies entirely on the engine's computer (ECU) tune to add the correct amount of fuel through the existing fuel injectors.

If you use the wrong jet size:

• Too large a jet $\rightarrow$ Engine will run dangerously lean, leading to severe engine damage (detonation).

• Too small a jet $\rightarrow$ Engine will run rich, resulting in poor performance.

Dry nitrous on a multi-port system like yours requires precise fuel tuning for the added power level. Do not use an estimated jet size without verifying the resulting Air/Fuel Ratio (AFR) on a dynamometer.