Overview of the 190E 2.3-16 Cosworth Mercedes
There was excitement among automotive experts on November 29, 1982: the third Mercedes-Benz model series--in the form of the long-awaited compact Mercedes-Benz 190E appeared on the automotive world stage. A sensation, as it would turn out, because in terms of design, suspension, engine and lightweight materials, this Mercedes differed distinctively from its brand brethren, the Mercedes mid-series, as it was called at the time. Today, the model designations are a lot simpler: C-Class, E-Class and S-Class.
The eagerly awaited 190E 2.3-16 certainly shook people up. It had already made its very first appearance in Italy on the high-speed test track in Nardo, near Lecce in southern Italy, to be precise. Three cars, only slightly cosmetically altered, had set three world records in August at the Nardo testing facility in Italy, recording a combined average speed of 154.06 mph (247.94 km/h) over the 50,000 km endurance test, and establishing twelve international endurance records.
When new Mercedes-Benz models make their first public appearance, their prototypes already have a hard time behind them, a tour de force to make them fit for a long automotive life with as little disturbance as possible. Yet it was rather unusual to stage the last acid test of outstanding performance in public – on a high-speed test track.
When this car was conceived as the top of the 190E range, the rear-wheel drive 2.3-16 was considered a credible way back into international motor sport. Its chassis was deemed capable, its weight distribution adequate and its position at the bottom of the Mercedes range absolutely perfect for maximum PR effect. All Mercedes needed was an engine, and this is where the 2.3-16 broke all the rules. Renowned for its solid engineering skills, Mercedes nevertheless chose to seek outside technical expertise for beefing up the 190E, from Cosworth Engineering of Northampton. Cosworth admits it was amazed to get the phone call from Stuttgart, but in fact it made perfect sense. Not only was Cosworth a safe bet as a technical partner in the planned re-entry into motor sport, it had also proved itself an expert in producing reliable four valve combustion engines, a technology still in its infancy in mass production. Mercedes had a reasonably powerful six-cylinder engine at hand, but it needed something more fiery for its racer, and so it delivered its standard M102, four-cylinder 2.3-litre block on Cosworth's doorstep, and commissioned a 16-valve cylinder head. And the 2.3-16 was born.
The new 2.3-liter four-cylinder engine with twin overhead camshafts in the 190E 2.3-16 was the first four-valve powerpack in a production Mercedes. Its light-alloy cylinder head, developed together with the British Cosworth company, had two camshafts, four V-shaped overhead valves per cylinder and pent-roof shape combustion chambers with a favorable geometry and spark plugs optimally located in the center. It was made from light alloy using Coscast's unique casting process and brought with it dual overhead camshafts and four valves per cylinder, meaning 16 valves total, which were developed to be the "largest that could practically be fitted into the combustion chamber". Precise mixture formation was ensured by mechanical Bosch KE-Jetronic fuel injection.
The engine (U.S. Spec) developed at 167 hp @ 5800 rpm and 162 lb·ft @ 4750, giving the car acceleration from standstill to 62 mph in 7.5 seconds and a top speed of 131 mph. The engine was combined with a manual five-speed transmission tuned for sporty performance. Self-leveling suspension on the rear axle was a standard feature.
The bodywork was aerodynamically modified to match the car's high performance. Front and rear aprons extended further down and a small spoiler on the trunk lid generated additional down force. Wheel arch flares covered the tires --wider than those of the 190E. Thus prepared, the car entered large-scale production.
Three of these production cars were slightly modified for record runs aimed at proving their reliability: the bodywork was lowered by 15 millimeters, the front apron was extended downwards by 20 millimeters, the fan was removed and the power steering replaced by mechanical steering. In the early morning of August 13, 1983, they started out on a 50,000 km high-speed test run, demanding stamina on the part of cars, drivers and test department staff. The Nardo cars also featured self-leveling suspension on the front axle to keep the ground clearance at a constant level.
The record track in Nardo is precisely 12.64026 kilometers long, has a diameter of some four kilometers and slightly banked lanes, thereby permitting driving almost without lateral forces even in the speed range over 140 mph.
According to the engineers' calculations, the cars were to reach the 50,000 km target in the morning of the eighth day – provided there were no problems, the pit stops were performed as scheduled and the six drivers were up to the strain. Lap times were to be three minutes and five seconds to reach the targeted average speed of 240 km/h including pit stops. Due to the cars' low Cd value of 0.30, they were expected to reach somewhat higher top speeds than the production versions.
Every two-and-a-half hours, the cars came in for refueling and a change of driver during a 20-second pit stop. The heavily strained rear tires had to be replaced every 8,500 kilometers and the front tires every 17,000 kilometers. During these five-minute tire change breaks, the oil and oil filters were also replaced and the valve clearance was checked. To protect the headlamp lenses against soiling and damage during the daytime, plastic caps covered them; the radiator mask was fitted with a quick-change insect screen to prevent clogging of the radiator.
After 201 hours, 39 minutes and 43 seconds, two of the cars had clocked up 50,000 kilometers. The replacement parts carried on board in compliance with the regulations had not been required – the cars had been running perfectly smoothly despite the extreme strain. The third car was laid up for three hours by a broken distributor rotor arm – an item costing just a few cents, which the pit crew were not allowed to replace but had to repair.
The new Mercedes-Benz 190E 2.3-16 had already more than fulfilled the hopes pinned on it when it became a crowd-puller at the Frankfurt Motor Show in September and a winner when it came to sales success.
In the following years, the 16-valve model formed the sound basis for the extremely successful Mercedes-Benz racing cars entered in the German Touring Car Championship (DTM).