You may be familiar with the “W126” Mercedes-Benz S-Class produced during the 1980-91 model years. But have you ever heard of the “822 Performance Package” factory option package that was available on European market 1986-88 sedans and coupes? Here, we’ll take a look at this interesting set of upgrades with a focus on European market models. First, we’ll start with some history about why the 822 package came to be.
BMW’s 12-CYLINDER SURPRISE
In the mid-1980s when it became known that BMW was working on a first ever 12-cylinder engine to put in their next generation 7-series flagship (codenamed the “E32”), Mercedes execs grew gravely concerned. Until that point, with the exception of one V8 built in limited numbers in the 1950s, BMW’s largest mass-produced engines never had more than six cylinders – giving Mercedes a clear advantage they had grown used to since the 1960s.
Now BMW sought to shift the paradigm by leapfrogging to twelve cylinders. The last-minute decision in 1984 to engineer such an powerplant required delaying the E32’s development in order to widen the vehicle’s body to fit the bigger engine. It also meant existing stamping presses and tooling that were already created for the 7-series had to be scrapped at great expense to fabricate new ones . Ultimately, BMW’s V12 engine created would displace 5.0 liters and produce 296 horsepower along with 347 lb-ft of torque.
Once Benz executives realized BMW’s revisions would delay the E32’s release date in Europe from the middle of calendar year 1985 to mid-1986 as a 1987 model, they sprang into action with a revised plan of updates to the W126 to prevent it from being left in the dust and dethroned from the title of “best sedan in the world”.
To coincide with the E32’s introduction which was originally set for late 1985 as an ‘86 model, Mercedes had planned a refresh of the W126 for the same 1986 model year. The updated “Generation 2” W126 received mechanical refinements and, most noticeably, new aero look wheels and side cladding. Anticipating BMW would bring out a new V8 engine, Mercedes enlarged all of their existing six- and eight-cylinder engines to produce more power. Their biggest V8 in production at the time displaced 5.0 liters (known as the M117 engine), and was enlarged to 5.6 liters via a lengthened compression stroke to produce either 241 or 272 horsepower depending if a catalytic converter was fitted.
The V12 surprise suddenly meant those planned changes weren’t going to cut it. Benz engineers now had a bigger challenge to measure up to, and a short time to do so. Developing a V12 for the W126 would take too long and wouldn’t be practical, as it would require re-engineering too many systems to make everything fit and run smoothly. Instead, Mercedes began working on a V12 for their next generation of S-Class, not the W126. (more on that later in this article).
During late 1984 and 1985, Mercedes worked overtime creating a high output 300-horsepower version of the 5.6-liter V8 engine to match the E32’ twelve-cylinder power. Classified internally as the hoch verdichting (high compression) “ECE” motor, this massaged mill featured a higher compression ratio of 10 to 1 (instead of 9:1), different camshafts, revised ignition timing, and a freer-flowing exhaust system with “Tri-Y” headers that was not designed to accept catalytic converters. Compared to the standard Euro 5.6 engine, the ECE produced significantly more torque as well. After testing and perfecting, it was introduced in October 1985 as an option on 1986 model 560SEL sedans and 560SEC coupes.
(Left: A 560SEL with the 822 Package performance option is shown testing during its development in 1985.)
But the 300hp ECE engine wasn’t all Mercedes whipped up. In fact, it was just part of a comprehensive high-performance & handling package known as the “822 option”. By checking the 822 box on the factory order sheet, buyers also got hydro-pneumatic suspension at all four wheels (in place of traditional coil springs) for buttoned-down handling at high speeds, an engine oil cooler, lightweight aluminum hood & trunk panels, and a 2.65:1 rear axle ratio which allowed these W126s to achieve peak performance on par with the BMW E32.
Left: W126s equipped with the 822 Performance Package feature a suspension height control switch to the left of the emergency flashers as seen here.
For comparison, the 2.65 axle ratio created higher engine revs and snappier performance than the more relaxed 2.47 ratio normally used on 420, 500, and 560 SE/SEL models. 822 package transmissions were calibrated to start in first gear at all times, unlike traditional V8 models which started in second gear unless full throttle was applied.
CHANGING EUROPEAN EMISSIONS LAWS AFFECTED THE ECE ENGINE
Because more and more countries in Europe were requiring catalytic converters for cleaner emissions by the mid-1980s, Mercedes offered two versions of the standard 1986 5.6-liter to suit various markets. A “KAT” version produced 241 horsepower and came with a catalytic converter fitted as standard. An “RUF” version designed to be retrofitted with a converter at a later point put out 272 hp. Both of these versions ran the standard 9:1 compression.
After a year or so on the market, BMW’s E32 7-series was proving to be a more serious competitor than ever before, prompting Mercedes to up compression ratios on both RUF and KAT standard model V8 engines from 9:1 to 10:1 in the middle of the 1988 model year. Engine knock sensors were added to retard engine timing should improper detonation (knocking) occur as to prevent improper running conditions and unburned fuel damaging catalytic converters.
With all these updates, the revised RUF standard 5.6-liter now produced 296 horsepower – rendering the ECE version that was incompatible with catalytic converters redundant and obsolete. At this point in March 1988, the ECE engine and 822 package were both discontinued. The revised KAT version now made 279 hp, a notable improvement from the prior 241.
After the 822 package was dropped, included items such as 4-wheel-hydropneumatic suspension, oil cooler, and more that were formerly required became separate, individual options.
AUTO MAGAZINE COMPARISONS OF THE 560SEL vs. 750iL
In the September 1987 issue of the British magazine Auto, Motor & Sport, the new 750iL was compared against a top-level 560SEL with 822 package. The 560SEL was commended for its better low-end torque, better responsiveness, and faster 0-60 time (thank the 2.67 rear axle), but critiqued for its lower refinement relative to the BMW 12-cylinder’s supreme smoothness at autobahn speeds.
In top speed (255 km/h vs. 242), coefficient of aerodynamic drag (0.34 vs. 0.36), and fuel economy (15.5l/100km vs. 16.8), the 750iL measured slightly better numbers all around. Despite being heavier than the Mercedes, magazine writers felt the 7-series absorbed bumps better and handled with less understeer and ponderousness.
Ultimately, they awarded the Top Sedan In The World title to the 750iL – writing, “to be fair, the Mercedes doesn’t surrender easily for a seven-year-old car” and, “in a performance-oriented society that is ever eager to reach for something better, one could still drive a 560SEL with peace of mind”. For more details on this review, see Christopher Butt’s full synopsis on driventowrite.com.
HOW TO TELL IF A 5.6 LITER ENGINE IS AN EARLY ECE or LATER 10:01 VARIANT
Checking your car for the presence of a high-performance 5.6 liter engine is relatively easy. On 1986-88 ECE engines, you’ll find “822” stenciled in paint on the back of the cylinder heads, and a code stamping on top of the engine that has “HV” as the last two characters. As noted earlier, HV signifies hoch verdichting (high compression) in German.
On mid-1988 through 1991 European 5.6-liters designed for catalytic converters, you’ll find a stamping of “10:1” on the engine instead of HV – referencing the 10:1 compression ratio that all Euro market V8s now had.
According to a Mercedes source, 10:1 compression 5.6-liters were put in chassis numbers A363799 onwards, with the exception of the following chassis numbers:
A 360603,A 360655,A 360679,A 362163,A 362184,A 362368,A 362452,A 362494,A 362538,A 362542,A 362553,A 362557,A 362601,A 362610, A 362621,A 362626,A 362630,A 362635,A 362640,A 362648,A 362651,A 362654,A 362660,A 362662,A 362673,A 362680,A 362687,A 362690, A 362696,A 362698,A 362732,A 362736,A 362737,A 362747,A 362770,A 362787,A 362791,A 362799-A 362802,A 362810,A 362814,A 362820, A 362824,A 362834,A 362838,A 362845,A 362847,A 362853,A 362867,A 362872,A 362879,A 362883,A 362899,A 362913,A 362914,A 362916, A 362918,A 362923,A 362928,A 362930,A 362932,A 362934,A 362937,A 362940,A 362942,A 362948,A 362950-A 362954,A 362958,A 362962, A 362967,A 362972,A 362974,A 362980,A 362984,A 362986,A 362989,A 362992,A 362994,A 362995,A 362998,A 363001,A 363009,A 363015, A 363020,A 363024,A 363030,A 363031,A 363033,A 363037, A 363039,A 363041,A 363043,A 363045,A 363047,A 363049,A 363050,A 363053,A 363055,A 363060,A 363061,A 363066,A 363068,A 363071, A 363073,A 363075,A 363079,A 363085,A 363090,A 363091,A 363095,A 363102,A 363109,A 363111,A 363112,A 363114,A 363122,A 363127, A 363129,A 363131,A 363134,A 363138,A 363139,A 363143,A 363148,A 363156,A 363157,A 363161,A 363162,A 363167,A 363168,A 363175, A 363176,A 363182,A 363186,A 363188,A 363190,A 363201,A 363202,A 363204,A 363215,A 363220,A 363226,A 363229,A 363231,A 363235, A 363237-A 363239,A 363243,A 363245,A 363247,A 363253,A 363254,A 363258,A 363261,A 363266,A 363272-A 363275,A 363279,A 363284, A 363285,A 363290,A 363291,A 363304,A 363306,A 363309,A 363310,A 363311,A 363314,A 363320,A 363324,A 363331,A 363334,A 363335, A 363339,A 363340,A 363347,A 363350,A 363353,A 363359, A 363366,A 363371,A 363377,A 363379,A 363383,A 363387,A 363388,A 363395,A 363396,A 363404,A 363406,A 363412,A 363415,A 363417, A 363419,A 363427,A 363435,A 363437,A 363439,A 363450,A 363455,A 363456,A 363459,A 363462,A 363464,A 363468,A 363469,A 363474, A 363475,A 363479,A 363482,A 363485,A 363486,A 363489,A 363492,A 363497,A 363501,A 363505,A 363508,A 363517,A 363518,A 363527, A 363533,A 363540,A 363543,A 363548,A 363550,A 363551,A 363553,A 363555,A 363557,A 363559,A 363561,A 363564,A 363573,A 363579, A 363583,A 363585,A 363593,A 363595,A 363598,A 363604,A 363605,A 363611,A 363618,A 363620,A 363622,A 363629,A 363631,A 363641, A 363643,A 363651,A 363653,A 363661,A 363664,A 363670,A 363675,A 363680,A 363683,A 363690,A 363703,A 363705,A 363714,A 363716, A 363721,A 363723,A 363730,A 363734,A 363745,A 363754, A 363758,A 363760,A 363764-A 363766,A 363771,A 363774,A 363776,A 363779,A 363782.
As an interesting footnote, the success of BMW’s 12-cylinder 7-series caused Mercedes to delay the planned introduction of the next-generation W140 S-Class by a few years in order to reconfigure for a 12-cylinder engine, which they needed time to create as well. So thanks to the E32, it’s safe to say the whole world was treated to at least two or three additional years of W126 production.
Left: Mercedes did introduce a V12 engine in their next-generation S-Class for the 1992 model year, known as the W140 body.
