Nitrous Jetting Calculator

Shot & system

Target HP shot

System type

Target fuel:nitrous ratio (by weight) Enter as 1:X — e.g. 5.5 means 1 part fuel to 5.5 parts nitrous by weight. Typical wet-shot range is 5–6.

This hypothetical area model rounds diameters to whole thousandths of an inch. Modeled horsepower is not verified hardware performance.

Presets:

Illustrative jet diameters

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Enter a target HP shot to see the algebra illustration.

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Nitrous jet

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Fuel jet

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Estimated actual HP

Enter a target HP shot to see the algebra illustration.

Wet-nitrous jet reference chart

Typical published wet-nitrous jet combos at a 1:5.5 fuel:nitrous ratio, for reference. Jet numbers are brand-specific in the real world — treat these as a general planning reference, not an exact match for any one kit.

HP shot	Nitrous jet	Fuel jet

4 min read 5 steps 7 terms 3 examples 6 FAQs nitrousJet ≈ √(targetHP ÷ k), where k = 100 ÷ 35² (anchored t…

This calculator demonstrates an area-scaling equation using a hypothetical anchor.

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Walk-through

How to Use This Calculator

5 steps

Enter your target HP shot

Type the horsepower gain you're aiming for — most street kits fall between 50 and 150 hp, while race-only setups can push higher. The calculator accepts anything from 25 to 400 hp.

Pick wet or dry

Choose Wet if your kit sprays both nitrous and fuel (fogger nozzle or plate system) — you'll get a fuel algebra illustration too. Choose Dry if the kit only adds nitrous and relies on the factory fuel system or ECU to richen up — no fuel jet is shown for dry systems.

Adjust the target fuel:nitrous ratio (wet only)

For the algebra demonstration, enter X in the ratio 1:X. Increasing X reduces modeled fuel flow. This is not a tuning recommendation.

Read the algebra illustration

The result card shows the nearest whole-jet-size nitrous jet (and fuel jet, if wet) plus the estimated actual horsepower that combo delivers — real jets only come in fixed sizes, so this won't always match your target exactly.

Check the fuel ratio and reference chart

Switch to the Fuel Ratio tab to see how close the illustrated diameters land to your target ratio, and the Jet Reference Chart tab for the full table of combos this calculator is built from.

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Reference

Formula & Methodology

3 formulas

Nitrous jet sizing (orifice-area scaling)

nitrousJet ≈ √(targetHP ÷ k), where k = 100 ÷ 35² (anchored to a .035" jet at 100 hp)

At a roughly constant bottle/line pressure, the mass flow through a jet scales with its orifice area — diameter squared, not diameter directly. This calculator anchors that relationship to a commonly published wet-nitrous combo (a .035" nitrous jet supporting a 100 hp shot) and scales the ideal jet diameter for any target HP from there, then rounds to the nearest whole thousandths-of-an-inch size actually sold.

Fuel jet sizing (wet systems)

fuelJet ≈ chosen rounded nitrousJet × (20 / 35) × sqrt(5.5 / X)

The illustrative .035-inch/.020-inch anchor is not a manufacturer specification. Fuel scaling uses the chosen rounded nitrous diameter before rounding the fuel diameter. Doubling X halves modeled fuel flow, so diameter scales by 1/sqrt(2).

Estimated actual HP

estimatedHP = (rounded nitrousJet)² × k

Because the recommended jet size is rounded to the nearest whole increment sold in real jet kits, the actual horsepower delivered by that jet is back-calculated from its exact diameter rather than assumed to equal your typed target.

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Glossary

Key Terms Explained

7 terms

Nitrous jet The removable orifice inside a nitrous solenoid or nozzle that meters how much nitrous oxide flows through the system. Sized in thousandths of an inch (e.g. a ".035" jet").

Wet system A nitrous kit that sprays both nitrous oxide and extra fuel together (through a fogger nozzle or a wet nitrous plate), keeping the air-fuel mixture correct as nitrous is added. Requires both a nitrous jet and a fuel jet.

Dry system A nitrous kit that injects only nitrous oxide into the intake and relies on the vehicle's existing fuel injectors — richened by the factory ECU or a piggyback controller — to supply the extra fuel. No separate fuel jet exists to size.

Fuel jet The orifice that meters extra fuel flow on a wet nitrous system, sized to keep the fuel:nitrous ratio in a modeled ratio as the nitrous jet is changed.

AFR (fuel:nitrous ratio) In a nitrous context, the ratio of fuel mass to nitrous mass delivered by the system — commonly expressed as 1:X (1 part fuel to X parts nitrous by weight). A illustrative ratio is around 1:5.5; running leaner than that risks detonation.

Nitrous shot The approximate horsepower increase a given nitrous jet combo is rated to add, e.g. a "100 hp shot" or "150 hp shot." Named after the jetting kit's rated output, not an exact guaranteed number.

Jet chart A manufacturer's reference table mapping nitrous and fuel jet sizes to a rated horsepower shot. Jet numbers and rated hp are brand-specific — a "jet 35" from one manufacturer doesn't necessarily flow the same as another's.

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Scenarios

Real-World Examples

3 worked examples

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Weekend street shot

100hp wet shot at the default 1:5.5 ratio

Target HP shot 100 System type Wet

Non-installable algebra illustration. The displayed diameters demonstrate scaling and rounding only; they do not validate a kit, installation, tune or safe shot.

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Bigger dry shot

150hp dry shot

Target HP shot 150 System type Dry

Non-installable algebra illustration. The displayed diameters demonstrate scaling and rounding only; they do not validate a kit, installation, tune or safe shot.

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Ratio check

125hp wet shot, checking the resulting ratio

Target HP shot 125 System type Wet

Non-installable algebra illustration. The displayed diameters demonstrate scaling and rounding only; they do not validate a kit, installation, tune or safe shot.

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Reference

Cite This Calculator

APA & MLA

Use either format to cite this calculator in a paper, report, or resource list.

APA

MLA

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Deep Dive

Understanding the Nitrous Jetting Calculator

3 chapters · 4 min read

This calculator demonstrates an area-scaling equation using a hypothetical anchor. It cannot select installable nitrous or fuel jets and cannot establish a safe horsepower shot.

How the Nitrous Jetting Calculator works

Non-installable algebra demonstration only. Real jet selection requires the exact kit manufacturer chart, fuel, bottle pressure, flowing fuel pressure, hardware and validated tune. The displayed anchor, ratios and diameter rounding have no generic installation or safety validity.

Inputs and what they mean

Limits and edge cases

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Questions

Frequently Asked Questions

6 questions

What's the difference between a wet and dry nitrous system?+

A wet system sprays nitrous oxide and extra fuel together — through a fogger nozzle in the intake tract or a plate under the throttle body — so it needs both a nitrous jet and a fuel jet sized to match. A dry system injects only nitrous oxide and relies on the vehicle's existing fuel injectors, richened by the factory ECU or a piggyback fuel controller, to supply the extra fuel that the added oxygen needs. Dry systems are simpler to install but depend entirely on the fuel system and tune already being able to supply enough extra fuel — there's no separate fuel jet to fall back on.

What's a typical fuel:nitrous ratio for a wet shot?+

The 1:5.5 value is an illustration, not a safe starting ratio. Follow the exact kit manufacturer instructions under their specified pressure and fuel conditions.

Does a bigger nitrous shot need a bigger fuel system?+

Often yes. As the nitrous jet gets larger to support a bigger horsepower shot, the wet system's fuel jet scales up proportionally to maintain the target ratio — which means more fuel volume has to be available at the fuel jet's supply line. On a dry system, a bigger shot demands more enrichment capability from the factory fuel injectors and pump, which may run out of headroom well before the nitrous jet does. This is one reason very large shots typically move to a dedicated wet system with its own fuel supply rather than staying dry.

What's a safe nitrous shot size for street driving?+

No generic safe shot can be established by this calculator. Do not install the illustrated jet pair. Use the exact manufacturer kit chart and all specified operating conditions and engine requirements.

Are nitrous jet numbers the same across all manufacturers?+

No — jet numbers are brand-specific. A "jet 35" from one manufacturer may flow a meaningfully different amount than a "jet 35" from another, because manufacturers use their own internal calibration and testing. This calculator's reference chart represents a generic, commonly published relationship between jet size and horsepower shot; treat it as a planning reference and confirm the exact jet-to-flow numbers against your specific kit's documentation before ordering jets.

What units does this calculator use?+

Target HP shot is in horsepower. Jet sizes are shown in thousandths of an inch (e.g. ".035\""), the standard way nitrous and fuel jets are labeled. The fuel:nitrous ratio is entered and displayed as 1:X by weight, where X is the number of parts nitrous per one part fuel.

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How to Use This Calculator

Enter your target HP shot

Pick wet or dry

Adjust the target fuel:nitrous ratio (wet only)

Read the algebra illustration

Check the fuel ratio and reference chart

Formula & Methodology

Key Terms Explained

Real-World Examples

Cite This Calculator

Understanding the Nitrous Jetting Calculator

How the Nitrous Jetting Calculator works

Inputs and what they mean

Limits and edge cases

Frequently Asked Questions

Get a branded PDF of your results

Keep Exploring

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Guides & articles

Glossary terms