BMW N43

The N43 is a 1.6 and 2.0-litre naturally aspirated four-cylinder petrol engine built from
2007 to 2013, and it is one of very few BMW engines with a genuinely unusual feature: direct
injection with spark-ignition lean-burn combustion. It was sold in Europe and never in the
United States.

What the N43 is

A naturally aspirated inline-four with direct petrol injection, designed to run a lean
mixture at part load — more air than the chemically ideal ratio — in order to reduce
throttling losses and fuel consumption. It sat alongside the N46,
which is the conventional port-injected engine of the same era and displacement.

Lean-burn petrol combustion produces nitrogen oxides that an ordinary three-way catalyst
cannot treat, which is why the engine needed additional aftertreatment and why its market
availability depended heavily on local fuel sulphur content. That is the practical reason an
engine like this appeared in some markets and not others.

Why it is not in our records

Our specification pages are built from United States government data: EPA fuel economy and
certification records and Transport Canada vehicle specifications. The N43 was not certified for
sale in North America and appears in none of them. Our brochure archive is a United States
archive, so it holds nothing describing the engine either.

The American four-cylinder story of those years is an absence. Our records contain no
four-cylinder BMW at all for model years 2000 through 2011 — twelve years — and the
next one is the turbocharged N20 in 2012. While Europe was choosing
between the N43 and the N46, the American range had no four-cylinder option.

What we do not publish

No reliability rating, no power figures, no specification table. Nothing on this page is
drawn from a government record or a brochure, because none of them cover a car that was never
sold here. The description above is general engineering description and is flagged as such.

Common questions

Which BMWs have the N43?

The E90 316i, 318i and 320i and the E60 520i, in European markets, from 2007 to 2013. None in
the United States.

What is the difference between the N43 and the N46?

Injection. The N46 uses conventional port injection; the N43 uses
direct injection with lean-burn operation at part load. Same displacement class, same years,
different combustion strategy — and BMW sold both at once.

Was the N43 sold in America?

No. No BMW four-cylinder of any kind was sold new in the United States between the 1999
M44 cars and the 2012 N20.

Sources

None for this engine. The absence of four-cylinder BMWs from the American market between
2000 and 2011 comes from EPA fuel economy data, which is named on every
specification page.