Forgotten Icons - E12 BMW M535i/5 Series

M535i

When you think of “M” you may think of cars like the E30 M3, or E60 M5. But here is something much older. The M535i, one of the first sports sedans.

The M535i was a sportier version of the 535i. However, it didn’t feature any M drivetrain components but a few things you wouldn’t find on a regular M535i would be the M-Technic suspension,the wheels and body panels. The E12 M535i is the only official BMW Motorsport-developed version of the E12 5 Series. It is the only E12 model powered by the SOHC 3.5-liter M30B35 inline-six from the E23 735i and E24 635CSi. It also has a BMW Motorsport chassis and some unique cosmetic items. European E12 M535i models were halfway assembled on the normal E12 5 Series production line at Dingolfing then hand-finished at the BMW Motorsport plant at Preussenstrasse in Munich. South Africans versions were assembled in BMW’s Rosslyn, South Africa factory from Complete Knock Down (CKD) kits from Germany.
The E12 M535i was introduced at the 1979 Frankfurt motor show. The E12 M535i never came to North America because the 3.5-liter M30 engine was not available with a catalyst at the time and therefore could not meet U.S. emission standards. Also, the addition of such equipment, as well as the various safety items needed, it would have reduced performance to essentially that of a North American 528i.

About the Normal E12 5 Series

The E12 was in production from 1972 to 1981, and was a perfect middle child to the larger E3 6 Series and the smaller 2002 which later became the 3 Series. This particular model was quite troublesome for BMW when they imported it to the US. With different regulations and safety laws BMW had to replace and modify many of the parts on this vehicle and because of that, the car was known overheating from warped or cracked cylinder heads. BMW offered replacement parts on all effected models in and outside of warranty which was a steep price. The E12 models were fitted with a many different engines. 1.8 L and 2.0 L M10B18-20 I4 engines. The 520i was also available with a 2.0 liter M20B20 engine and used the mechanical fuel injection system from the BMW 2000tii and BMW 2002tii. The six-cylinder 520i made 120 horsepower and 160 Nm (120 lb-ft) of torque. While the four-cylinder 520i made 125 horsepower and 171 Nm (126 lb-ft) of torque. US-spec E12s in the later years were sold as ‘upscale’ models and were fitted with power windows, wood trim, leather interiors and air conditioning as standard. BMW only sold fuel-injected six-cylinder versions of the E12 5 series in the American market, the 530i and later the 528i. BMW claimed to have sold around 700,000 E12s between 1972 and 1981, and that’s correct as far as German production goes, which stopped just after 699,094 units. But in South Africa, BMW’s first foreign factory, another 23,100 were built up until 1984, only for the local market.

M535i Specs

Length: 4618 mm

Weight: 1391 kg

Engine: 3.5 litre, 3453 cm3

Cylinders: 6

Power: 218 PS / 215 bhp / 160 kW at 5200 rpm

Torque: 304 Nm / 224 ft.lb / 31 kgm at 4000 rpm

0-60 mph: 6.9 s

0-100 km/h: 7.2 s

Top speed: 228 km/h, 142 mph

The M535i's Drivetrain, Suspension And Chassis

The E12 M535i is powered by the earliest version of the M30B35 inline-six with a bore of 93.4mm and a stroke of 84.0mm for a total displacement of 3,453cc. This SOHC iron-block unit uses Bosch L-Jetronic fuel injection and produces 218 hp at 5,200 rpm and 224 lb/ft of torque at 4,000 rpm. This engine was not offered with emission controls.

There were two different five-speed manual gearboxes availbable on the E12 M535i. All European models were equipped with the close-ratio unit featuring a dogleg shift pattern, ratios: 3.72 (1), 2.40 (2), 1.77 (3), 1.26 (4), 1.00 (5). This gearbox was also offered as an option on the South African-built model, even though most were equipped with the more common overdrive manual transmission with the following ratios: 3.82 (1), 2.20 (2), 1.40 (3), 1.00 (4), .81 (5). Regardless of the gearbox option, all E12 M535i models were equipped with a 3.07:1 final drive and limited slip differential (LSD).

The basic suspension design of the E12 M535i is similar to that of all E12 5 Series models as mentioned earlier, with MacPherson struts in front and a semi-trailing arm design in the rear. However, it has been tuned by BMW Motorsport and is therefore equipped with unique springs and Bilstein shocks. Steering is by recirculating ball, with engine-speed-sensitive power assist and an overall ratio of 16.9:1.

All the E12 M535i models have four-wheel disc brakes. The vented front rotors measure 11-inches (280mm) in diameter and are not larger than those fitted to other six-cylinder E12 models. However, at 25mm in thickness, they are 3mm thicker than all other E12 rotors. The solid rear rotors measure 10.7-inches (272mm) in diameter and are identical to those used on other E12 models. ABS wasn’t an option.
E12 M535i models are fitted with 195/70VR14 tires but was available different wheel options. All European models are equipped with 6.5x14-inch BBS cross-spoke alloys while South African versions use a slightly wider 7x14-inch version of a similar design made by BBS/Mahle. They also feature unique center caps bearing the BMW Motorsport logo.

Exterior/Interior

What makes the difference is the exterior of the E12 M535i that can be identified by its unique body-color front airdam that looks much different from the regular 535i, black rubber rear spoiler and iconic tri-color BMW Motorsport stripes on the side bodywork and front airdam. However, these items were technically listed as optional equipment and could be removed upon request in order to give the car the stealthy appearance of a standard 535i. In addition, the M535” grille and decklid badging could be deleted as well. However, the 14-inch cross-spoke alloy wheels were fitted to every M535i.

The South African M535i was not offered with the front airdam, rear spoiler or Motorsport stripes from the European model. However, it was equipped with the M535i grille and decklid badging as well as a pair of large front foglights. It was also fitted with 7x14-inch BBS/Mahle cross-spoke alloy wheels featuring special center caps bearing the BMW Motorsport logo.

The M535i shares its basic design and layout with the standard E12 5 Series, the interior of the E12 M535i includes two special features: Front sport seats made by Recaro covered in a unique fabric, leatherette or the optional leather (ASS sport seats in black cloth with central Motorsport stripes were also available by special order from BMW) and a three-spoke leather-wrapped steering wheel featuring the BMW Motorpsort logo, identical to the one used in the iconic M1 sports car.

The interior of the South African built E12 M535i is identical to the German built version, but it is fitted with additional standard equipment including air conditioning, power windows and central locking.

The factory option list for the E12 M535i included fog lights (not available with the front and rear spoilers), headlight washer/wipers, passenger-side rearview mirror, leather upholstery (or leatherette at no extra charge), sport seats with Motorsport stripes, passenger seat height adjustment, velour floor mats, fire extinguisher, rear headrests, green tinted glass, brown tinted glass, air conditioning (including green-tinted glass), manual sunroof, power sunroof, power windows (all around or front only), central locking, various audio systems and a power antenna. In addition, the front airdam, rear spoiler and Motorsport exterior stripes were listed as “special equipment,” at extra charge. Right-hand drive models (both ECE and South African) included many of these optional items as standard equipment.

Special Editions

There were no official factory special editions of the E12 M535i. However, an earlier “Motorsport Special Edition” E12 530i was produced as a homologation special by BMW South Africa in 1976, and this model can actually be considered a direct predecessor to the M535i. It is also worth mentioning that the M535i lived on in South Africa until 1984 as part of the updated E12 range that was assembled for the local market as an interim series until production of the E28 began there in 1985. These 4709 models have some of the later E28 features. The Motorsport Limited Edition E12 530 was partly developed by BMW of South Africa and BMW Motorsport GmbH in order to homologate the 3.0-liter 5 Series sedan for competition in the South African Modified Production class. The production of 100 road cars was required under the homologation rules, it is thought that around 216 street-legal examples of the Motorsport Limited Edition 530 were ultimately produced, all in 1976.

At the time, the largest engine available in a standard production E12 was the 2.8L inline-six. However, the Motorsport Special Edition 530 was equipped with a larger 3.0-liter M30B30 motor based on the unit from the E3 sedan and E9 coupe but featured twin Zenith carburetors, a special camshaft, lightened flywheel and an engine oil cooler. It was rated at 197 hp at 6,000 rpm and 204 lb/ft of torque at 4,300 rpm. It had the close-ratio five-speed manual gearbox featuring a dogleg shift pattern and a Borg-Warner limited slip differential (LSD). The chassis was upgraded with Bilstein shocks like on the M535i, stiffer springs and thicker anti-roll bars similar to those fitted to the special German-built E12 530 models offered by BMW Motorsport starting in 1974. In addition, the cars were equipped with four-wheel disc brakes and 195/70VR14 tires on BBS/Mahle cross-spoke alloy wheels.

The Motorsport Limited Edition 530 was offered in three different paint colors, they were Ice White, Platinum metallic or Sapphire Blue metallic, all paired with tri-color BMW Motorsport stripes. The body featured fender lip extensions as well as the fiberglass front and rear spoilers. In order to reduce weight, several body panels were made of aluminum or thinner steel, the pedals and trunk hinges were drilled for further weight saving, and thinner glass was used for all the windows except the front windshield. Inside, these special 530 models were fitted with Scheel sport seats covered in blue velour and equipped with a three-spoke sport steering wheel. The rear bench seat was mounted to a foam base in order to reduce weight even further.

This model should not be confused with the later E12 530 Motorsport Edition of 1977-80, which was a standard production model for the South African market that did include the 3.0-liter M30 motor, limited slip differential, Bilstein shocks, Mahle magnesium wheels, Scheel sport seats and blacked-out exterior trim.

An E28-based successor to the original E12 M535i did not appear in German built version until early 1985, an updated E12 M535i was introduced as part of the facelifted South African E12 5 Series range in the Fall of 1981. This unique E12/E28 M535i hybrid model was known as Model 4709, it retained the older E12 bodywork and mechanicals, but had an updated the interior to include many components from the newer E28 5 Series (not produced in South Africa until 1985). Power was once again provided by the 3,453cc version of the M30B35 inline-six, rated at 214 hp at 5,200 rpm and 229 lb/ft of torque at 4,000 rpm. This could include either the overdrive or close-ratio version of the five-speed manual gearbox, both of which were paired exclusively with the taller 3.07:1 final drive and limited slip differential (LSD). The chassis was also carried over from the existing E12 M535i. BMW South Africa assembled 1,416 examples of the “Model 4709” E12 M535i between September of 1981 and December of 1984. It was then replaced by the actual E28 successor to the E12 M535i in January of 1985.