The Different Types of CO2 Cars: From Classroom Dragsters to Road Vehicles

CO2 cars generally fall into two meanings: small, cartridge-powered “CO2 dragsters” used in education and competitions, and road vehicles categorized by their carbon dioxide emissions or powertrain type. In short, the former includes body and class variations such as rail, wedge, and shell/bullet designs, while the latter spans internal-combustion, hybrid, plug-in hybrid, electric, and fuel-cell vehicles, often grouped by regulatory CO2 standards. Below, we break down both uses of the term and explain how each category is defined and compared.

What “CO2 cars” can mean

When people ask about “types of CO2 cars,” they typically refer to one of two contexts—either the school or hobbyist model cars propelled by CO2 cartridges, or the broader market of road vehicles differentiated by their CO2 emissions and propulsion technology. The following list clarifies these two interpretations so you can find the information that matches your need.

• CO2 cartridge dragsters: Lightweight model cars powered by a punctured CO2 cartridge, raced over a short track in classrooms and competitions.
• Road vehicles categorized by CO2: Passenger cars and light-duty vehicles classified by tailpipe CO2 emissions and powertrain type (ICE, hybrid, PHEV, BEV, FCEV), or by regulatory CO2 labeling schemes.

Understanding which meaning applies helps you focus on either design and performance factors for dragsters or emissions and technology choices for road-going cars.

CO2 cartridge dragster types

CO2 dragsters are a staple of STEM programs worldwide. They use a small pressurized CO2 cartridge for thrust and race along a tethered track. While exact rules vary by organizer, the broad “types” are best described by body style, competition class, and performance factors.

Body and design styles

Design styles primarily balance aerodynamics, weight, and structural constraints. The list below outlines common approaches seen in classrooms and competitions.

• Rail: A narrow, skeletal frame minimizing frontal area and mass; popular for reducing drag but requires careful stiffness and alignment.
• Wedge: A tapered block with a low, sloping nose; easy to fabricate and reliably aerodynamic for beginners.
• Shell/Bullet: Smooth, enclosed shapes with rounded noses and tapered tails; emphasizes streamlined flow at the cost of more complex shaping.
• Aerofoil/Winged: Incorporates airfoil sections to manage airflow; often used to stabilize and reduce pressure drag while keeping weight low.
• Freeform/Concept: Custom sculpted designs that experiment with surface curvature, wheel shrouds, and innovative layouts within rule limits.

Each style trades off ease of construction, structural integrity, and aerodynamic efficiency; competition constraints (like minimum cross-sections and wheel clearance) heavily influence what works best.

Competition classes and specifications

Many programs define classes to keep racing fair and safe. While specifications differ by event, these are the most common distinctions you’ll encounter.

• Kit/Stock vs. Open/Custom: Kit classes use standard blanks, axles, and wheels; open classes allow more freedom in materials, shaping, and components.
• Cartridge and track standards: Most events use an 8-gram CO2 cartridge and a straight, tethered track over roughly 20–25 meters; launch and timing systems are standardized for safety and consistency.
• Dimensional and safety rules: Mandated limits for length, width, wheelbase, minimum material around the cartridge, and weight floors to ensure structural safety and fair competition.

Before building, teams should consult the exact rulebook for their event (e.g., school districts, TSA, technology challenges) because allowed dimensions, minimum mass, wheel types, and testing procedures vary.

Performance factors

Fast runs come from managing airflow, weight, and friction while maintaining stability. The following factors matter most for CO2 dragster performance.

• Aerodynamics: Low frontal area, smooth finish, gradual tapering, and minimal flow separation reduce drag.
• Mass distribution: Light overall weight within rules and balanced front/rear loading improve acceleration and tracking.
• Rolling resistance: True-running wheels, low-friction bushings/bearings, precise axle alignment, and proper clearances cut losses.
• Stability and alignment: Straight axles, square geometry, and good center-of-gravity placement prevent scrub and zig-zagging.
• Cartridge integration: Clean, centered mounting and an unobstructed nozzle path ensure consistent thrust; launch alignment matters.

Optimizing these areas usually yields bigger gains than extreme styling alone; consistency and build precision are key.

Road vehicles categorized by CO2

In consumer markets, “CO2” usually refers to emissions measured in grams per kilometer (g/km) or grams per mile (g/mi). Vehicles are broadly grouped by their propulsion technology and by regulatory labeling that indicates CO2 output under standardized test cycles.

Types by powertrain and typical CO2 implications

The powertrain determines whether a car emits CO2 at the tailpipe and how much. Here’s how major categories compare.

• Internal-combustion engine (ICE: gasoline/diesel): Emits CO2 at the tailpipe; efficiency and fuel type determine actual g/km.
• Mild hybrid (MHEV): Adds starter-generator assistance; reduces CO2 modestly versus comparable ICE but still tailpipe-emitting.
• Full hybrid (HEV): Can drive short distances on electric power; lower CO2 than ICE in city-heavy duty cycles, still tailpipe-emitting overall.
• Plug-in hybrid (PHEV): Larger battery with external charging; very low CO2 on short trips if charged regularly, but emissions rise on long, engine-heavy drives.
• Battery electric vehicle (BEV): Zero tailpipe CO2; lifecycle CO2 depends on grid mix and manufacturing.
• Fuel-cell electric vehicle (FCEV): Zero tailpipe CO2 when using green hydrogen; lifecycle impact depends on hydrogen production method.
• CNG/LPG vehicles: Typically lower CO2 than gasoline per unit energy, but still tailpipe-emitting.
• E-fuel/biofuel ICE: Tailpipe CO2 similar to fossil fuels, with potential lifecycle reductions if fuels are sustainably produced.

Real-world CO2 depends on driving patterns, maintenance (e.g., tire pressure), and energy sources used for charging or fuel production.

CO2 rating and labeling systems you’ll see

Governments and agencies publish standardized CO2 figures and labels to help buyers compare models. The following examples show how different regions present CO2 data.

• European Union/UK: WLTP-based g/km figures on consumer labels; many countries use color-graded A–G style ratings. Fleet-average CO2 targets push automakers toward lower-emission models.
• United States: EPA labels include estimated CO2 emissions (g/mi) and a greenhouse gas rating; state incentives may hinge on these metrics.
• China and other markets: Localized fuel-economy and CO2 labeling plus “dual-credit” or compliance systems encourage low-emission vehicles.

Because test cycles and label designs differ, the same car can show different CO2 numbers across regions; use local labels for apples-to-apples comparisons.

Lifecycle (well-to-wheel) CO2 considerations

Beyond tailpipe ratings, total climate impact includes energy production and manufacturing. These factors shape the bigger CO2 picture.

• Electricity mix: BEV CO2 improves as grids add renewables; charging times and locations matter.
• Fuel pathways: Hydrogen, e-fuels, and biofuels vary widely in CO2 depending on production methods and feedstocks.
• Manufacturing footprint: Battery and materials production add upfront emissions; these are often offset over the vehicle’s life with clean energy use.
• Usage patterns: Long highway trips vs. urban commutes, and charging diligence for PHEVs, significantly affect real-world CO2.

Considering lifecycle helps avoid misleading conclusions based solely on tailpipe measurements, especially when comparing BEVs, PHEVs, and efficient ICEs.

Summary

“CO2 cars” most often refers either to cartridge-powered classroom dragsters—classified by body style and competition rules—or to road vehicles grouped by their CO2 emissions and propulsion systems. Dragsters vary by designs like rail, wedge, and shell/bullet and are governed by event-specific specifications. Road vehicles range from ICE and hybrids to BEVs and FCEVs, with regional labels reporting CO2 under standardized tests. For performance, focus on aerodynamics, weight, and friction in dragsters; for road cars, compare CO2 labels, consider your driving patterns, and factor in lifecycle emissions to choose the most climate-efficient option for your needs.

What are the different types of CO2 cartridges?

CO2 cartridges are differentiated by their thread type (threaded or non-threaded) and size in grams (e.g., 8g, 12g, 16g, 20g, 25g, 88g), though the most common sizes vary by application, with smaller sizes for bike tires and larger sizes for airsoft guns or industrial uses. Always confirm the cartridge type, especially thread size and weight, matches your device to ensure compatibility and proper function.
 
By Thread Type

• Threaded Cartridges: Opens in new tabThese cartridges screw into the inflator head or device, allowing for a more secure connection and better control over gas flow. 
• Non-Threaded (Push-In) Cartridges: Opens in new tabThese simply push into the inflator head. They are less common but are still used in some applications. 

By Size (in Grams)
The amount of CO2 in a cartridge is measured by its weight, with different sizes suited for different tasks. Common sizes include: 

• 8g: Often used for smaller, quick inflation needs.
• 12g: A very common size, especially in the US, used in airguns.
• 16g: Suitable for inflating standard bike tires.
• 20g: Also good for bike tires and other standard inflation.
• 25g: Used for larger volume tires or other applications.
• 38g: Another size recommended for larger applications.
• 88g: Larger capacity cartridges used in airsoft guns and other high-volume devices.

By Application

• Bicycle Inflation: Smaller, lighter cartridges (like 16g or 20g) are ideal for road and standard bike tires. 
• Airsoft & Airguns: Larger cartridges, such as 88g and 12g, are frequently used with airsoft pistols and airguns. 
• Beverage Dispensing: Cartridges are used to carbonate drinks, though these are a different type of cylinder. 
• Industrial Applications: Larger tanks and specific valves are used for industrial-grade CO2, which differs from consumer-grade cartridges. 

What makes the fastest CO2 car?

Simply put, the less weight your dragster has, the faster it will go. This is the most important factor that will figure into your design. Keep it light! Thrust: The gas escaping from the CO2 cartridge in the car.

What are the three main types of CO2 dragsters?

There are 5 main types of C02 dragsters and if a C02 dragster does not fit into one of the 5 catigories, then its not a C02 dragster. They are Rail, Show, Shell, Model, and Normal.

What are CO2 cars?

A CO2 car is a lightweight model dragster powered by the sudden release of compressed carbon dioxide gas from a punctured cartridge. These cars are often used in STEM education to teach physics principles like Newton’s laws of motion, as students design, build, and race their own dragsters down a designated track. The gas escaping backward creates an equal and opposite force that propels the car forward.
 
This video demonstrates how CO2 dragsters work and explains the science behind their propulsion: 55sPitsco EducationYouTube · Mar 10, 2016
How CO2 cars work:

1. 1. Design and Build: Opens in new tabStudents design and build the car body, usually from lightweight materials like balsa wood, and attach wheels and axles. 
2. 2. Propulsion System: Opens in new tabA CO2 cartridge is inserted into a hole at the rear of the car. 
3. 3. Launch: Opens in new tabThe cartridge is placed in a starting gate, where a firing pin pierces the cartridge, releasing the compressed CO2. 
4. 4. Motion: Opens in new tabThe escaping gas rapidly expands and pushes the car forward down the track, guided by a string or wire to prevent it from veering off course. 

Educational Applications:

• Physics Principles: Opens in new tabCO2 dragsters are excellent tools for teaching Newton’s Laws of Motion, aerodynamics, and concepts like mass, force, and acceleration. 
• Engineering Skills: Opens in new tabStudents learn about design, construction, and problem-solving as they work to create a fast and stable vehicle. 
• Math Skills: Opens in new tabThe project involves calculations related to measurement, multiplication, division, and estimation to achieve optimal performance. 

Key Characteristics:

• Lightweight: Made from balsa wood or other light materials to maximize acceleration. 
• Streamlined: Designed for speed and to minimize air resistance and friction. 
• Guided: A fishing line or wire runs through screw eyes under the car to keep it on the track.