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On The Road

The language of luxury: Getting to the bottom of the letters and numbers on cars

Courtesy of BMW
BMWs, such as these specially painted for a breast-cancer-awareness campaign, are differentiated by strings of numbers and letters that may not mean much to the consumer at first glance.

The upscale auto world has long dismissed the idea of naming cars.

When it's time for product planners to name their pride and joy, they skip past the dictionary of everyday communication and dive into coded strings of letters, numbers and decimal points. Because of psychological forces understood only to marketing geniuses (or a complete lack of imagination), anonymity has come to equal prestige.

To people who never learn the language, it can also equal misunderstanding. It doesn't help that every maker uses a different code, that most of them revamp their code every few years, or that many of them have contradictions and redundancies and are whimsical about following their own rules. Kind of like English.

Here are some examples:


BMW has at least employed the same basic system since the mid-1970s. For a long time now, there have been a 3-series, 5-series and 7-series. Each has grown over the years - today's 3-series is larger than the 5-series of the past - but they have grown together. Basically, 3, 5 and 7 means small, midsize and large sedan, respectively. This number is given away in the first digit of every BMW's name.

Following that digit are two more that denote engine displacement in metric liters. BMW now has the following engines in its lineup: 2.5-liter six (184 horsepower), 3.0-liter six (225 hp), 3.2-liter six (333 hp), 4.4-liter V8 (325 hp), 4.8-liter V8 (355 hp) and 6.0-liter V12 (438 hp)

Easy example: the cheapest model in BMW's lineup is the 325i: a 3-series sedan powered by a 2.5-liter six. A 330i is a 3-series sedan with a 3.0 six. A 545i is a 5-series sedan with a 4.4 V8. Hold the phones - shouldn't that be "544i"? Nope, because BMW recently decided to round up to the nearest .5 liters. This is probably a better solution than the brief period in 1998-2000 when a 3-series with a 2.5-liter engine was randomly dubbed "323" before being restored to "325" in 2001, even though the engine never changed.

If you guessed that "i" means sedan, you'd usually be correct. It used to stand for "fuel injection," but that indicator has been unnecessary for years. While we're on letters, "Ci" either means coupe or convertible, even though as recently as the late '90s, "is" meant coupe as well. "Ci" first started getting use on the 8-series back in 1993, replaced "is" when the new 3-series coupes came out in 2000, and now that it's also used on the new 6-series coupes, it finally enjoys consistent and exclusive use. "iT" denotes BMW wagons, as it has for a while. Right now, its only starring role is to put a badge on the 325iT, the only remaining wagon in BMW's lineup. "X" refers to 3-series models with all-wheel-drive: the 325xi and 330xi sedans and the 325xiT wagon. Finally, the "L" in 745Li and 760Li stands for long, as in a longer-by-5.5-inches wheelbase. It used to be "iL" in 7-series cars, but BMW has flip-flopped it.

But when is a 5-series not a 5-series? When it's a 6-series. One of BMW's other new laws is to designate even numbers to two-door versions of odd-numbered cars. The Z3 was reborn as the Z4 in 2003, and when the new 5-series sedan came out for 2004, the coupe and convertible were dubbed 6-series.

BMW seems to be following Mercedes' cue of positioning coupes above sedans - something that's already reflected in the 6-series' $20,000-higher price tag - so assigning them numerically higher names supports that idea. When the new 3-series coupes come out for 2007, the coupes and convertibles will be the 4-series. At around the same time, we can look for the first-ever 2-series, since the two-door version of the 1-series is the only version we'll get. Once coupes and convertibles have their own numbers, the whole "Ci" thing will probably be unnecessary, won't it?

The 3-numbers-followed-by-1-letter system bows down to the letter "M." The company's motorsports tuner division pumps up any BMW car to maximum power, then sticks the "M" in front, followed by the series number. The M3 is the fastest 3-series, just as the M5 will be the fastest 5-series. Note that there's no hint of body style or engine displacement. If you must know, the M3 has a 3.2-liter, 333 hp V6 and comes as a coupe or convertible, and the M5 sedan and M6 coupe will both have the same 500 hp 5.0-liter V10.

Ever since BMW began expanding into roadsters and SUVs in the mid-'90s, letters started coming first elsewhere. "Z" seems to stand for roadster, as the late Z3 and current Z4 are two-seat convertible variations of the 3-series (the four-seat convertible remains part of the 3-series). Engine displacement is simply given away verbatim; the Z4 lineup consists of "Z4 2.5i" and "Z4 3.0i." Hmm, so much for "i" standing for sedan.

As Z means roadster, "X" marks the spot for SUV when it comes first (X, remember, is all-wheel drive). In a similar manner, X3 means 3-series SUV and X5 means 5-series SUV and engines are again stated afterward. There are two X3s - 2.5i and 3.0i - and three X5s: 3.0i, 4.4i, and 4.8is. Hey, what's the deal with "is"? Didn't it used to mean coupe, and didn't BMW jettison it in 1999? The X5 4.8is is a four-door SUV, just like other X5s. Sigh.


Naming conventions at BMW's archrival are a little less clean. Mercedes-Benz hit the reset button in 1994 and finally injected some sense into the system. Obviously, for every mainstream BMW, there's a mainstream Benz, so the 3-, 5- and 7-series now butt heads with the C-class, E-class and S-class. Mercedes' 2005 engine lineup consists of the Supercharged 1.8-liter 4 (189 hp), 2.6-liter V6 (168 hp), 3.2-liter V6 (215 hp), 3.2-liter 6 Diesel (201 hp), 3.5-liter V6 (268 hp), 3.7-liter V6 (232 hp), 4.3-liter V8 (275 hp), 5.0-liter V8 (288, 292, or 302 hp), 5.4-liter V8, (362 hp), Supercharged 5.4-liter V8 (469 hp), Twin Turbocharged 5.5-liter V12 (493 hp) and Twin Turbocharged 6.0-liter V12 (604 hp).

Mercedes puts the series letter first, followed by the two digits for engine displacement, then a zero, i.e. a C320 is a C-class with the bigger 3.2-liter V6.

But Mercedes is even more random than BMW. Kicking off the C-class line is the C230, overstating its 1.8-liter engine by a good half-liter. Next up is the C240, undercutting its 2.6-liter V6 by 0.2 deciliters. The C320 is true to its name, but the new-for-2005 C55 slips up again by only offering 5.4 liters, as is the case with every Mercedes with "55" in its name.

That applies to C-class sedans, wagons and hatchbacks. C-class coupes and convertibles fall under the "CLK" lineup, as Mercedes often blurs the relation between genetically similar cars by dramatically altering appearances. The first-generation CLK (1998-2002) was a notably misleading example, having obviously been styled to resemble the E-class. The CLK line also shares the E-class' engines, starting with the V6-powered CLK320, working through the V8-powered CLK500 and ending with the CLK55. The motivation, obviously, is so they can charge E-class prices: the CLK320 and CLK55 are $7,300 and $16,000 more expensive than their C-class sedan equivalents.

The C-class roadster gets its own name as well - "SLK" - which actually means something: Sport, Light, Kompact. The SLK350's 3.5-liter engine is exclusive to it (for now), while the SLK55's V8 is shared with the C55 and CLK55.

As mentioned, the midsize E-class shares the CLK's engine lineup, so there's an E320, E500 and E55. All come as sedans; the first two also as wagons. And there's a diesel-powered E320 CDI sedan.

At the high end is the big, imposing, sedan-only S-class, starting with the S430 and its smaller 4.3 V8 not available in lesser Benzes. The S500 brings back the now-familiar 5.0 V8 and the S55 brings the supercharged 5.4 V8, but the top-of-the-line, $125,000 S600 carries a grand 5.5-liter twin turbo V12, which strangely carries the exact same power rating as the supercharged V8: 493 hp.

Splitting out from the S-class are the confusing-named CL coupes and legendary SL roadsters. Each takes the S-class' basket of engines, drops the bottom one, and adds one on top. The results are the CL500/SL500 (5.0 V8), CL55/SL55 (supercharged 5.4 V8), CL600/SL600 (turbo 5.5 V12), and CL65/SL65 (turbo 6.0 V12). That last one is new for 2005, setting an all-time record at Mercedes for both power (604 hp) and price ($179,720). Just as the CLK/SLK cost much more than the C-class on which they're based, the SL/CL costs more than equivalent S-class sedans. They also cost more than the nearest BMW rival, the 6-series.

Mercedes was one of the early ones in the luxury SUV arena with its ML-class, which still exists today to battle the X5. Starting off, the again-wrongly named ML350 gets a 3.7-liter V6 with 232 horsepower not shared with any other model. The ML500 finishes the lineup because the ML55 is gone. A new 2006 ML-class will be released very soon.

Mercedes has no equivalent to BMW's X3, but there is a tough, boxy Hummer-basher known as the G-class. G500 and G55, end of story.

Two-digit models are tuned by the AMG division, Mercedes' equivalent of BMW's M. AMG models are supposed to be the fastest, meanest, and most expensive Mercedes, but that claim's a little far-fetched since all AMGs are automatic-only. Also, the theme doesn't always carry all the way to top, as the S55 and SL55 neither outpower nor outprice the mainstream S600 and SL600. But since there's a C55 sedan, CLK55 coupe and convertible, SLK55 roadster, E55 sedan, S55 sedan, CL55 and CL65 coupe, SL55 and SL65 roadster, and G55 SUV, at least there's more of them. At BMW, the M3 is the only game in town at the moment.


Audi's numbers don't mean anything, but with a relatively simple lineup, they probably don't need to. Audi is straightforward about everything, even if they've been taking their sweet time settling down on a system.

Back in the '80s, American Audis were out of whack with the rest of the world; our 3-series and 5-series fighters were dubbed 4000 and 5000. In 1988, the new 4000s were renamed 80 and 90 to bring us in line with the world; the same thing happened in 1989 with the 5000s, which were renamed 100 and 200. In 1990, we got Audi's first big sedan, simply tagged the Audi V8 after its engine

In 1996, everything started over. The 80/90, 100/200, and V8 became the A4, A6, and A8 that we know today (the new naming system coincided with the release of the A4).

Audi has only a handful of engines (many shared with parent Volkswagen) but every model wears its engine right after its model designation. Going through the A4 line, A4 1.8T models have a turbo 1.8-liter 4 and A4 3.0 models have a 3.0-liter V6, both significant for having five valves in every cylinder. With the A4's mid-2005 refreshing, those will give way to a turbo 2.0-liter 4 and 3.1-liter V6, both with five valves per cylinder plus direct fuel injection.

The redesigned-for-2005 A6 starts with the A6 3.2 (which actually has a 3.1 V6 - yes, Audi lies too) and ends with the A6 4.2, hinting at its V8. The Allroad model is basically a rugged-looking wagon version of the 1998-2004 A6 and comes with that car's uplevel engines: 2.7T (2.7-liter turbo V6) and 4.2 (V8).

The V8 is the only engine in the large A8, which comes as an A8 or A8 L. L means the same thing it means at BMW: long wheelbase. Anywhere at Audi, T means turbo and "Avant" means wagon. Sport versions have an "S" replacing the "A" (i.e. the S4 is the ultimate A4) which always carries a more potent engine (in the S4's case, a 340 horsepower V8) and Quattro. Quattro, available on every line, designates all-wheel-drive models and is mandatory on Allroad, A6 and A8.

As the last Audi, the TT coupe and roadster insert near the bottom. TTs come with the 1.8T engine in two different outputs (180 and 225 hp) or with a 250 hp 3.2 V6. Audi simply distinguishes the three TT models by their horsepower ratings, and each is stuck with its own unique transmission. 180-hp TTs are front-drive and automatic; 225 hp TTs are Quattro and manual; 250-hp TTs are Quattro and Direct Shift Gearbox.

Sy is a former Palo Alto resident who writes for the Web site automotive.com.

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