What Is the Least Common Engine Placement?

The least common engine placement in modern production cars is the rear-engine layout, where the engine sits behind the rear axle. While front-engine designs dominate and mid-engine layouts serve performance niches, true rear-engine vehicles have become exceedingly rare—largely surviving in a handful of specialty models, most notably the Porsche 911. In electric vehicles, rear-mounted motors are increasingly common, but those are motors, not combustion engines.

How Engine Placement Types Compare

Automakers have historically used three main layouts for internal-combustion powertrains. Each affects handling, packaging, and efficiency in distinct ways, which explains why some are far more prevalent than others.

• Front-engine: The most common. The engine sits ahead of the cabin, driving the front or rear wheels. Favored for cost-effectiveness, cooling efficiency, crash safety, and interior space.
• Mid-engine: The engine sits between the axles, typically behind the seats. Popular in high-performance cars for balanced handling and weight distribution.
• Rear-engine: The engine sits behind the rear axle. Once widespread in early economy cars and a few luxury models, it’s now a niche choice due to packaging, handling, and regulatory challenges.

These layouts evolved with technology and regulations; front-engine cars became the default for mainstream buyers, while mid-engine sports cars and the rare rear-engine vehicles serve specialized roles.

Why Rear-Engine Layouts Are Rare Today

Rear-engine cars have unique benefits—excellent traction off the line and distinctive dynamics—but several practical and regulatory pressures have pushed the industry away from them.

• Packaging trade-offs: A rear engine can limit trunk space and complicate cabin packaging compared with front-engine designs.
• Cooling complexity: Effective radiator placement and airflow are more difficult at the rear, adding engineering costs.
• Handling constraints: With so much weight behind the rear axle, tuning predictable, forgiving handling for everyday drivers is harder.
• Safety and crash structures: Meeting modern crash standards and pedestrian protection with a rear engine can be more complex and expensive.
• Cost and scale: Front-engine platforms are ubiquitous, making them cheaper to produce and share across model lines.

Taken together, these factors make rear engines a tough business case except for brands that can charge premiums or that deliberately pursue the layout’s unique character.

Where You’ll Still Find Rear Engines

Current production examples

In today’s internal-combustion market, only a few models continue with rear engines, primarily for heritage and performance identity.

• Porsche 911 (current 992 generation): The standout modern example, retaining its signature rear-mounted flat-six for brand character and dynamic traits.

Beyond the 911, modern internal-combustion rear-engine offerings are effectively nonexistent in mainstream production, underscoring how unusual the layout has become.

Recently discontinued or historical modern-era models

Several recent city cars and historical models illustrate how the rear-engine layout once found broader use before being phased out.

• Renault Twingo III (2014–2024, Europe): Rear-engine city car, now discontinued as Renault pivots to electrification.
• Smart ForTwo (ICE, 1998–2019): Used a rear-mounted engine; the brand has since transitioned to EVs.
• Volkswagen Beetle (classic, 1938–2003): The archetypal rear-engine car, produced for decades across multiple regions.
• Chevrolet Corvair (1960–1969): A notable American rear-engine experiment.
• Tatra sedans (various, mid-20th century): Luxury and executive cars from Czechoslovakia that used rear engines.

These examples show the layout’s past breadth—from budget-friendly city cars to distinctive luxury sedans—before modern regulations and economics narrowed its appeal.

Electric vehicles: a related but different trend

Many modern EVs place an electric motor at the rear axle (for example, numerous rear-wheel-drive models on Volkswagen’s MEB platform and Tesla’s base Model 3/Y variants). However, that’s motor placement, not an internal-combustion engine layout. In EVs, rear-motor designs are often chosen for efficiency, packaging flexibility, and traction—but they don’t revive the traditional “rear-engine” architecture.

Historical Context

Rear-engine cars enjoyed a lengthy mid-20th-century run, particularly in Europe, for reasons of simplicity, cost, and space efficiency when engines and cooling systems were smaller and regulations lighter.

• Economy icons: Volkswagen Beetle, Fiat 500 (original), Škoda 1000 MB.
• Engineering outliers: Tatra’s air-cooled, rear-engine sedans prioritized aerodynamic innovation.
• American experiment: Chevrolet Corvair tried to bring the formula to the U.S. market.

As safety, emissions, and consumer expectations advanced—along with front-wheel drive and transverse engine packaging—the rear-engine layout receded to niche status, mainly preserved by Porsche’s 911 lineage.

Bottom Line

The rear-engine layout is the least common engine placement in modern cars, now largely confined to the Porsche 911 and a few specialty or historical models. While EVs often use rear-mounted motors, that trend doesn’t change the rarity of true rear-engine internal-combustion vehicles.

What is the least common type of engine placement?

The least common type of engine placement is a mid-engine configuration, where the engine is located between the front and rear axles but behind the passenger compartment. This layout is rare because it is expensive, compromises passenger and cargo space, and is typically reserved for high-performance sports cars due to its superior handling and weight distribution. 
Why Mid-Engine is Rare 

• High Cost: Mid-engine cars are more expensive to design and build, making them inaccessible for most consumers.
• Space Limitations: The engine’s placement significantly reduces passenger legroom and luggage capacity.
• Complexity: The complexity of the drivetrain and cooling systems also adds to the cost and engineering challenges.

Examples of Mid-Engine Cars Lamborghini Aventador, Ferrari 456, and Porsche 718 Cayman (a mid-engine model). 
Comparison to Front and Rear Engine Placements

• Front-Engine: Opens in new tabThe most common layout, offering the best compromise of cost, space, and practicality for everyday vehicles. 
• Rear-Engine: Opens in new tabAlso uncommon but found in performance vehicles like the Porsche 911. It improves traction and acceleration but can suffer from tricky handling and oversteer. 

What is the most inefficient engine?

Reciprocating engines. Reciprocating engines at idle have low thermal efficiency because the only usable work being drawn off the engine is from the generator.

What is the best engine placement?

The mid-engine is most commonly found in high-performance cars because its placement near the rear axle gives it a low centre of gravity and better acceleration. For those who want to become an auto mechanic, it’s important to note that a mid-engine layout also lends an ideal weight distribution to the car.

What is the most common engine layout?

The inline engine, particularly the inline-four configuration, is the most common engine configuration in the automotive world due to its simple, compact, and cost-effective design. Inline engines feature cylinders arranged in a single, straight row, which provides smooth operation, efficient power output, and ease of manufacturing and maintenance, making them ideal for a wide range of small to medium-sized vehicles.
 
This video explains the inline engine configuration and its benefits: 59sBladed AngelYouTube · Apr 6, 2018
Why Inline-Four is So Common

• Compactness: The inline design is efficient for space, especially in front-wheel-drive vehicles where space is at a premium. 
• Simplicity: It has a straightforward design that is easier and cheaper to manufacture and maintain. 
• Balance: With the cylinders in a straight line, the engine tends to run smoothly with minimal vibration. 
• Versatility: The configuration is adaptable for various vehicles, from economy compact cars to mid-range sedans and even some high-performance models with the addition of turbochargers. 

This video shows the different engine configurations, including the V engine: 59sThe Engineers PostYouTube · Jan 2, 2023
Other Common Configurations
While inline engines are most prevalent, other configurations exist and are popular for specific applications: 

• V-Engine: Opens in new tabCylinders are arranged in a V-shape, which makes the engine more compact than an inline engine for a given number of cylinders. 
• Boxer Engine: Opens in new tabCylinders lie horizontally on opposite sides of the crankshaft, creating a lower center of gravity and enhanced stability. 
• Rotary Engine: Opens in new tabUses a triangular rotor spinning inside a chamber instead of traditional cylinders and pistons.