Model nomenclature
Since 1972, BMW model names have generally been a 3 digit number is followed by 1 or 2 letters
the first digit represents the chassis type (e.g. 3 series, 5 series)
the last two digits represent the engine displacement in litres times 10.[7]
the letters provide additional information on the model variant (see below).
Commonly used letters at the end of the model name are:
C = coupé, last used on the BMW E46 and the BMW E63 (dropped after 2005 model year)
c = cabriolet
d = diesel
e = eta, an engine tuned for fuel efficiency rather than power (from the Greek letter 'η')
h = hydrogen
i = injected (fuel injection)
L = long wheelbase
s = sport, this can represent either upgraded interior/cosmetic options or increased engine power depending on the model. For the E36 range, all models with "s" in the name were coupes/convertibles)
sDrive = rear wheel drive
T = touring (wagon/estate)
t = hatchback for the BMW 3 Series hatchback
td = "Turbo Diesel" ( 524td, 525td/s, 324td, 325td/s, 318tds), or hatchback diesel ( E46 Compact 318td, 320td; E36 Compact 318tds)
x / xDrive = BMW xDrive all wheel drive
For example, the BMW 760iL is a fuel-injected 7 Series with a long wheelbase and 6.0 liters of displacement. A 318i represents a 3 series with a 1.8 L engine, in this case the "i" means that the engine is fuel-injected. This badge was used for successive generations, E65 and F01.
When 'L' supersedes the series number (e.g. L6, L7, etc.) it identifies the vehicle as a special luxury variant, featuring extended leather and special interior appointments. The L7 is based on the E23 and E38, and the L6 is based on the E24.
When 'X' is capitalized and supersedes the series number (e.g. X3, X5, etc.) it identifies the vehicle as one of BMW's Sports Activity Vehicles (SAV), their brand of crossovers, featuring BMW's xDrive. The second number in the 'X' series denotes the platform that it is based upon, for instance the X5 is derived from the 5 Series. Unlike BMW cars, the SAV's main badge does not denote engine size, the engine is instead indicated on side badges.
The 'Z' identifies the vehicle as a two seat roadster (e.g. Z1, Z3, Z4, etc.). 'M' variants of 'Z' models have the 'M' as a suffix or prefix, depending on country of sale (e.g. 'Z4 M' is 'M Roadster' in Canada).
Previous X & Z vehicles had 'i' or 'si' following the engine displacement number (denoted in liters). BMW is now globally standardizing this nomenclature on X & Z vehicles by using 'sDrive' or 'xDrive' (simply meaning rear or all wheel drive, respectively) followed by two numbers which vaguely represent the vehicle's engine (e.g. Z4 sDrive35i is a rear wheel drive Z4 roadster with a 3.0 L twin-turbo fuel-injected engine).[8]
The 's' code has meant different things at different times. The E30 325iS was an options pack for the 325i, however the E30/E36 318iS models used different engines to E30/E36 318i models. The 's' code was dropped in 1999 after the 325tds model (the last use in North America was for the 1995 325is). However, the 's' code was revived on the 2011 model year BMW 335is and BMW Z4 sDrive35is. The 335is has a more powerful engine, sports options and an optional dual clutch transmission that slots between the regular 335i and top-of-the-line M3.[9][10]
The 'M' – for Motorsport – identifies the vehicle as a high-performance model of a particular series (e.g. M3, M5, M6, etc.). For example, the M6 is the highest performing vehicle in the 6 Series lineup. Although 'M' cars should be separated into their respective series platforms, it is very common to see 'M' cars grouped together as its own lineup on the official BMW website.
A similar nomenclature is used by BMW Motorrad for their motorcycles.
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Exceptions
There are exceptions to the numbering nomenclature,[11] most commonly relating to SUV models, turbocharged engines and differing specification despite the same engine capacity.
SUV models
The M versions of the X5 M and X6 M, could not follow the regular naming convention, since "MX5" was used for Mazda's MX-5 Miata and MX-6.
Turbocharged engines
The 2008 BMW 335i and 535i also have 3.0-liter engine; however the engines are twin-turbocharged (N54) which is not identified by the nomenclature. Nonetheless the '35' indicates a more powerful engine than previous '30' models that have the naturally aspirated N52 engine. The 2011 BMW 740i and 335is share the same twin-turbo 3.0 N54 engine, although the badging is not consistent ('40' and 's'). Due to the move to turbocharged engines, the 2009 750i has a 4.4 L turbocharged engine, compared with a 4.8 L naturally-aspirated engine for the 2006 750i.
Due to the increased use of turbocharging recently, it will become increasingly common for the last two digits to not represent the engine capacity (for example the F30 328i uses a turbocharged 2.0 litre engine).
Different specification levels but same engine capacity
In the 2008 model year, the BMW 125i, 128i, 328i, and 528i all had 3.0 naturally aspirated engines (N52), not a 2,500 cc or 2,800 cc engine as the series designation number would lead one to believe. The '28' is to denote a detuned engine in the 2008 cars, compared to the 2006 model year '30' vehicles (330i and 530i) whose 3.0 L naturally aspirated engines are from the same N52 family but had more output.
A similar situation occurred with the E36/E46 323i and E39 523i models. These models all used 2.5 litre engines. However, the previous 325i and 525i models were higher in the model range than their replacements, therefore the replacements were called 323i and 523i (which also provided a bigger gap to the future 328i and 528i models). BMW has not produced a 2.3 litre gasoline engine since the early 1990s.
The opposite situation occurred with the 1996 E36 318i, since it used a 1.9 L engine (M44) as opposed to the 1.8 L (M42) used in the 1992 to 1995 models. This was done to avoid changing the model code for the base model (i.e. otherwise consumers would need to be taught that the base model was now called 319i).
Another example of an exception is the 1980s 325e and 525e models. These cars actually used 2.7 litre engines (which were tuned for fuel economy rather than power).