The Mitsubishi Toppo 657 U, produced from 1990 to 1999, represents a significant entry in the Japanese Kei car class, though it wasn’t directly marketed in the United States. This small, three-door hatchback was designed to navigate the congested urban landscapes of Japan, offering an affordable and practical transportation solution. The “657 U” designation refers to its engine displacement, a key characteristic defining vehicles within the Kei car regulations. While modest in power by American standards, the Toppo 657 U served a vital role in its domestic market and found limited export success in other regions, particularly in Europe as a budget-friendly city car.
Mitsubishi Toppo 657 U: A Kei Car Overview
The Mitsubishi Toppo, in its various iterations, was a mainstay of Mitsubishi’s Kei car lineup for decades. The 657 U model, specifically, was part of the second generation of the Toppo, introduced in 1990. Kei cars are a unique segment of the Japanese automotive industry, defined by strict regulations regarding size and engine displacement. These regulations offer tax and insurance benefits to owners, making Kei cars exceptionally popular in Japan. The Toppo 657 U, with its 657cc engine, fell squarely within these parameters, offering a compact and economical vehicle for daily commuting.
Engine & Performance
Powering the Mitsubishi Toppo 657 U is a small, 657cc inline three-cylinder petrol engine. This engine produces 40 horsepower at 6000 rpm and 51 Nm (37.62 lb-ft) of torque at 4000 rpm. While these figures may seem low compared to larger vehicles, they were adequate for the Toppo’s intended purpose – navigating city streets and short commutes. The engine is naturally aspirated and utilizes a carburetor fuel injection system, a common feature for vehicles of this era. The power-to-weight ratio is 16.8 kg/Hp, or 59.7 Hp/tonne, and the torque-to-weight ratio is 13.1 kg/Nm, or 76.1 Nm/tonne. The Toppo 657 U is equipped with a three-speed automatic transmission, providing ease of use for urban driving. The front-engine, front-wheel-drive configuration contributes to its maneuverability and fuel efficiency.
Design & Features
The Mitsubishi Toppo 657 U is a three-door hatchback, designed to maximize interior space within its compact footprint. It seats five passengers, although rear passenger space is limited. The vehicle’s design prioritizes practicality over aesthetics, with a focus on functionality and ease of parking. The body dimensions are 3295 mm (129.72 in) in length, 1395 mm (54.92 in) in width, and 1765 mm (69.49 in) in height. The wheelbase measures 2260 mm (88.98 in). Safety features for the time included front disc brakes and rear drum brakes, along with an Anti-lock Braking System (ABS) as an available option. The steering system is a rack and pinion type, providing responsive handling. The vehicle rides on 12-inch wheels with 135/80 R12 S tires.
Technical Specifications
| Brand | Mitsubishi |
| Model | Toppo |
| Generation | Toppo |
| Type (Engine) | 657 U (40 Hp) Automatic |
| Start of production | 1990 year |
| End of production | 1999 year |
| Powertrain Architecture | Internal Combustion engine |
| Body type | Hatchback |
| Seats | 5 |
| Doors | 3 |
| Fuel Type | Petrol (Gasoline) |
| Weight-to-power ratio | 16.8 kg/Hp, 59.7 Hp/tonne |
| Weight-to-torque ratio | 13.1 kg/Nm, 76.1 Nm/tonne |
| Power | 40 Hp @ 6000 rpm |
| Power per litre | 60.9 Hp/l |
| Torque | 51 Nm @ 4000 rpm / 37.62 lb.-ft. @ 4000 rpm |
| Engine layout | Front, Transverse |
| Engine displacement | 657 cm3 / 40.09 cu. in. |
| Number of cylinders | 3 |
| Engine configuration | Inline |
| Cylinder Bore | 65 mm / 2.56 in. |
| Piston Stroke | 66 mm / 2.6 in. |
| Compression ratio | 9.8:1 |
| Number of valves per cylinder | 2 |
| Fuel injection system | Carburettor |
| Engine aspiration | Naturally aspirated engine |
| Valvetrain | OHC |
| Kerb Weight | 670 kg / 1477.1 lbs |
| Fuel tank capacity | 32 l / 8.45 US gal | 7.04 UK gal |
| Length | 3295 mm / 129.72 in |
| Width | 1395 mm / 54.92 in |
| Height | 1765 mm / 69.49 in |
| Wheelbase | 2260 mm / 88.98 in |
| Front track | 1215 mm / 47.83 in |
| Rear (Back) track | 1215 mm / 47.83 in |
| Drivetrain Architecture | The Internal combustion engine (ICE) drives the front wheels of the vehicle. |
| Drive wheel | Front wheel drive |
| Number of gears and type of gearbox | 3 gears, automatic transmission |
| Front suspension | Spring Strut |
| Rear suspension | Coil spring |
| Front brakes | Disc |
| Rear brakes | Drum |
| Assisting systems | ABS (Anti-lock braking system) |
| Steering type | Steering rack and pinion |
| Tires size | 135/80 R12 S |
| Wheel rims size | 12 |
The Mitsubishi Toppo 657 U, while not a performance vehicle, offered a practical and affordable transportation solution within the constraints of the Japanese Kei car regulations. Its compact size, fuel efficiency, and ease of use made it a popular choice for urban commuters. Though largely unknown in the United States, the Toppo represents a significant part of Japan’s automotive history and a testament to the ingenuity of designing efficient vehicles for densely populated areas.
