The 18-month car.

Nikkei BP, a Japanese technology publisher, sells a 494-page teardown of the BYD Seal for ¥880,000, about $6,000. Japanese carmakers and suppliers buy it. Forty years ago, the world bought books about Japanese factories.

The book found an eight-in-one power unit, a battery built into the floor, and very few control units. Each part BYD merges is one less supplier to negotiate with and one less test to wait for.

Reuters puts the traditional time from concept to launch at about five years. In 2025 the engineering firm AVL measured today’s carmakers for Nikkei. China’s electric-car makers took about half as long as Japan and Europe.

Other estimates agree within a few months. They differ on when the count starts and stops.

Chery’s published process takes about 35 months. GAC says it went from 26 months to 18 to 21 after it adopted integrated product development (集成产品开发, jíchéng chǎnpǐn kāifā), the method Huawei uses. GAC also reports R&D costs down more than 10%.

McKinsey splits development into three stages. The stages that prepare the factory barely change. The design and validation stage shrinks by almost two-thirds. Chinese carmakers decide much sooner that a design is ready.

Chinese electric-car makers run about 65% of their tests on computers, against 40 to 50% at Western carmakers. They build about half as many physical prototypes. Zeekr says it checks a turn signal in software in about 30 minutes.

The idea comes from Toyota. In 2000 Stefan Thomke and Takahiro Fujimoto called it front-loading: Toyota found about 80% of its problems by the end of detailed design.

Chinese carmakers keep software separate from hardware. A car can launch with its software unfinished and improve through updates sent over the air. During joint work on the bZ3, Toyota engineers were reported to be “flabbergasted” at how readily BYD made major design changes late.

When the battery, motors and electronics come from your own divisions, nobody waits on a supplier. ITIF found a supplier design change takes 2 to 3 months in China and 3 to 4 years in the West. Zeekr says its engineers search 20 years of Geely designs for an existing part before they draw a new one.

Rhodium Group compared a BYD Seal with a Tesla Model 3. Of a cost gap of about $4,700 per car, it credits $2,369 to making parts in-house and $292 to government subsidies.

Chinese carmakers also put more engineers on each car, and those engineers work long weeks. Six days a week, about 12 hours a day, is normal in Chinese electric-car engineering. Zeekr hands work between Shanghai and Gothenburg so that a project moves about 20 hours a day.

In 2021 a 35-year-old BYD worker died suddenly after a month with 26 shifts of nearly 12 hours. Lean calls this overburden (無理, muri). A system that depends on it carries a cost it has not removed.

In June 2025, 17 carmakers promised to pay suppliers within 60 days. A year later, investigators found most still paid much later, often with commercial notes, a promise to pay at a future date.

Quality shows strain too. BYD recalled cars for battery defects, and regulators now require carmakers to file software updates before they send them. Teardowns do not find cheap cars, though. Caresoft found “no corners cut” in the $12,000 BYD Seagull. The risk is uneven quality and failures that only show up after years.

In the 1980s Kim Clark and Takahiro Fujimoto studied 29 car projects at 20 carmakers. Japanese projects took about two-thirds of the time of American ones and half the engineering hours: 1.7 million against 3.4 million.

Detroit first blamed culture. The study found method: a chief engineer (主査, shusa) with real authority, design steps that overlapped, and suppliers who engineered their own parts. US carmakers adopted the method and caught up by the mid-1990s. Chrysler developed the Neon in 31 months.

Nikkei reports that Nissan is bringing the Chinese method back to Japan, a reverse import (逆輸入, gyaku yunyū). Other carmakers are doing the same.

Japan’s lead in the 1980s lasted until its rivals studied the method. These carmakers are now studying China’s.