What Size Engine Does NASCAR Run?

NASCAR vehicles utilize 358 cubic inch (5.9 liter) V8 engines. These powerplants produce approximately 670 horsepower and operate at speeds up to 9,000 rpm. NASCAR engines are purpose-built for racing, featuring advanced designs and materials to maximize performance within strict regulations.

The engines in NASCAR come from three manufacturers: Chevrolet, Ford, and Toyota. While each brand supplies its own parts, the engines must adhere to specific NASCAR guidelines. This ensures a level playing field while allowing for some brand differentiation.

NASCAR engines are built for short-term, high-intensity use. Unlike street cars designed to last 100,000 miles or more, these racing engines typically endure for just two race weekends before requiring a rebuild. This extreme focus on performance over longevity sets NASCAR engines apart from their consumer counterparts.

NASCAR Engine Basics

NASCAR engines are powerful, purpose-built V8s designed for high-performance racing. These engines have evolved over decades while maintaining certain core characteristics.

Current Engine Specifications

NASCAR Cup Series engines are 358 cubic inch (5.87 liter) pushrod V8s. They produce around 670 horsepower on most tracks and 510 horsepower on superspeedways. The engines are naturally aspirated and use a single 4-barrel carburetor for fuel delivery.

Key components include:

• Cast iron engine block
• Aluminum cylinder heads with 2 valves per cylinder
• Flat-tappet camshaft
• 12:1 compression ratio

These V8s rev up to 9,000 RPM and generate over 500 lb-ft of torque. Strict rules govern engine design to keep costs in check and maintain competitive balance between teams.

History and Evolution of NASCAR Engines

NASCAR engines trace their roots back to modified production V8s. In the 1960s and 70s, teams used 427 and 429 cubic inch engines based on street car designs.

The 358 cubic inch limit was introduced in 1974 to curb escalating power and speeds. Over time, NASCAR standardized more engine specs:

• 1991: Mandated iron blocks and limited valve sizes
• 2012: Fuel injection replaced carburetors
• 2015: Tapered spacer reduced horsepower

While maintaining a classic pushrod V8 layout, NASCAR engines have become highly specialized racing powerplants. Modern units share little with production car engines beyond basic architecture.

Regulations and Limitations

NASCAR maintains strict rules for engine specifications to promote fair competition and safety. These regulations cover power output, component usage, and fuel capacity.

NASCAR Regulations

NASCAR limits engine power to 670 horsepower for most tracks, with a 510 horsepower cap for superspeedways. This standardization aims to level the playing field and enhance racing quality. Teams must carefully optimize torque within these constraints to maximize performance.

Engine components are subject to specific regulations. NASCAR mandates the use of certain parts and prohibits others to control costs and maintain competitive balance. Fuel capacity is also regulated, with specific limits set for different race types and track lengths.

Restrictor Plates and Their Impact

Restrictor plates are devices used to limit engine power on certain tracks. These metal plates with four small holes are placed between the carburetor and intake manifold, reducing airflow to the engine.

NASCAR introduced restrictor plates to slow cars down at high-speed tracks like Daytona and Talladega. This measure improves safety by keeping speeds in check. While restrictor plates reduce top speeds, they also lead to tighter pack racing as cars have similar power outputs.

The use of restrictor plates has sparked debate among drivers and fans. Some argue they make racing safer, while others claim they reduce the skill factor and increase the risk of multi-car crashes.

Technical Aspects of NASCAR Engines

NASCAR engines are highly specialized V8 powerplants designed for maximum performance within strict regulations. These engines incorporate unique features to optimize power, reliability, and efficiency on the track.

Fuel Delivery Systems

NASCAR engines use a single four-barrel Holley carburetor to deliver fuel. This traditional system contrasts with modern production cars that use electronic fuel injection. The carburetor allows precise control over fuel-air mixture and throttle response.

Carburetors are simpler and easier to adjust than electronic systems, giving teams more flexibility during race weekends. They also provide instant throttle response, crucial for drivers making split-second decisions on the track.

Some tracks require restrictor plates to limit airflow into the engine, reducing power output for safety reasons.

Engine Power and Performance

NASCAR Cup Series engines produce around 750 horsepower on tracks 1 mile or shorter and 550 horsepower on longer tracks. These V8 engines have a displacement of 358 cubic inches (5.9 liters) and can rev up to 9,800 rpm in certain race conditions.

Engine blocks are typically made of iron for durability, while cylinder heads are often aluminum to reduce weight. High-flow intake valves and carefully designed exhaust systems help maximize airflow and power output.

Teams use dynamometers to fine-tune engine performance and measure power output under controlled conditions.

Aerodynamics and Engine Design

Engine design in NASCAR is closely tied to aerodynamics. The shape and placement of engine components affect the car’s overall aerodynamic profile.

A dry sump oiling system allows the engine to sit lower in the chassis, improving the car’s center of gravity and handling. This system also provides superior oil control during high-G cornering and acceleration.

The air intake and exhaust systems are designed to work with the car’s body shape, optimizing airflow both into the engine and around the vehicle. This integration helps teams achieve peak performance while staying within NASCAR’s strict rules.

Teams and Manufacturers

NASCAR engines are produced through a collaborative effort between racing teams and manufacturers. This partnership drives innovation and performance in stock car racing.

Role of Racing Teams in Engine Development

Racing teams play a crucial part in NASCAR engine development. Top teams like Hendrick Motorsports invest heavily in research and development to gain a competitive edge. They work closely with manufacturers to refine engine designs and improve performance.

Teams employ skilled engineers and technicians who specialize in engine tuning and optimization. These experts fine-tune engines for specific tracks, adjusting parameters to maximize speed and fuel efficiency.

Racing teams also conduct extensive testing to evaluate engine performance under race conditions. This data helps identify areas for improvement and guides future development efforts.

Engine Suppliers and Manufacturers

Three major manufacturers supply engines for NASCAR: Ford, Chevrolet, and Toyota. Each brand produces engines that meet NASCAR’s strict specifications while incorporating unique design elements.

Ford uses its FR9 engine, developed specifically for NASCAR competition. Chevrolet engines are based on the R07 design, while Toyota Racing Development (TRD) produces engines for Toyota teams.

These manufacturers work within NASCAR’s rules to create powerful V8 engines capable of producing over 750 horsepower. Engine designs are optimized for high-speed tracks like Daytona and Talladega, as well as shorter circuits like Pocono Raceway.

With the introduction of the Next Gen car, NASCAR has standardized many components to reduce costs and improve competition. However, engine development remains an area where manufacturers and teams can gain an advantage through innovation.