Saturday, September 22, 2012

A Dream: E28 M5

E28 M5 / M535i - 1985 to 1987

What makes the E28 M5 unique?
The E28 M5 is the BMW Motorsport-developed version of the E28 5 Series. It uses the M88 or S38 twin-cam 24-valve inline-six first introduced in the M1. It also has a BMW Motorsport-tuned chassis and a few special cosmetic pieces.
Where was the E28 M5 first introduced?
The M5 debuted at the 1985 Amsterdam Motor Show.
Where was the E28 M5 built?
Unlike the other E28 5 Series models, M5s were assembled by a small group of BMW Motorsport technicians who mated the drivetrain and interior trim with pre-painted bodies transported from the Dingolfing factory. This hand-assembly took place in one of two facilities, depending on the production date. E28 M5s produced before September of 1986 were assembled at BMW Motorsport’s original Preussenstrasse location near the BMW AG headquarters in Munich, while E28 M5s built beginning in 9/86 were assembled at the newly-opened BMW Motorsport headquarters in Garching, roughly 100 kms (60 miles) east of Munich. The only exceptions were M5s produced for the South African market, all of which were assembled at BMW’s Rosslyn, South Africa factory from German-supplied Complete Knock Down (CKD) kits.

Why was BMW sued by American E28 M5 owners?
When BMW of North America first anounced the E28 M5 in late 1986, production was said to be limited to 500 cars. But by the time production ended in November 1987, however, almost triple that number had been produced. Thus, a class action lawsuit was filed against BMW by E28 M5 owners who claimed that the collector’s value of their cars was diminished by the greater volume. The company settled the case by giving these owners a rebate on the purchase of a new BMW.
Why are all North American-spec E28 M5s officially 1988 models if the last example was made in 1987?
This was most likely a marketing decision. With the M5 originally intended to be a limited edition of 500 cars, and with the entire E28 range due to be replaced by the E34 for 1989, perhaps BMW of North America wanted to keep the E28 M5 exclusive by offering it only for the final 1988 model year. Also, it is worth noting that production of the other 1988 5 Series models began in early 1987, so the M5 preceeded these by only a few months.
Why are all North American E28 M5s essentially identical?
Because the E28 M5 was hand-assembled, yet needed to be manufactured for the North American market in relatively large numbers within a relatively short amount of time, BMW of North America was forced to limit the model’s specification to just two color schemes: Black (086) with a Natur (tan) leather interior and (officially for Canada only) Black (086) with a black leather interior.
Why is a North American E28 M5 with a black leather interior so rare?
Though a Natur (tan) extended leather interior was the only official interior color choice for the U.S. market, Canada insisited on giving E28 M5 buyers the second option of a black extended leather interior. The black interior option was later expanded to the U.S. market at the very end of E28 M5 production. In total, 102 E28 M5s with a black interior were produced for North America, of which 72 were built to Canadian specification and the rest to U.S. specification.

Production Data
How many versions of the E28 M5 were developed?
BMW Motorsport built four different versions of the E28 M5, three at the M works in Garching, Germany (European-spec in left-hand drive and right-hand drive, plus the North American version) and a South African-spec model for the home market assembled from Complete Knock Down (CKD) kits. Only the North American version utilized the catalyst-equipped S38 version of the M88 motor.
How many of each version were produced?
ECE (LHD without catalyst): 588 produced from 10/84 through 9/87
ECE (RHD without catalyst): 187 produced from 3/86 through 11/87
NA (LHD with catalyst): 1,340 produced from 11/86 through 11/87
SA (RHD without catalyst): 96 produced (assembled from CKD kits) from 6/87 through 11/88*
*Dates shown indicate final completion of vehicles assmebled in Rosslyn, South Africa.
What changes were made to the E28 M5 during its production?
Though all North American-spec E28 M5s are essentially identical, there were some alterations to the European-spec E28 M5 that occurred over the course of its production. These include:
-Change from “M” shift knob lapel (with shift pattern as sticker on ashtray lid) to regular shift pattern lapel (early 1985 production)
-Change from light grey to anthracite headliner and trunk liner (early 1985 production)
-Introduction of optional BMW Sound System (11/85 production)
-Introduction of optional driver-side airbag (11/85 production)
-Introduction of different rear springs (2/86 production)
-Introduction of optional Shadowline (dechromed) exterior trim (5/86 production)
-Introduction of (optional in most markets) 16-inch cross-spoke alloy wheels (5/86 production)
-Introduction of Boge (in place of of Bilstein) shocks (approximately 10/86 production)
-Introduction of 25mm (front) and 18mm (rear) anti-roll bars (10/86 production)
-Introduction of map lights in rear-view mirror (10/86 production)
-Introduction of door sill plates with the “M5” logo (10/86 production)

Does every example of the E28 M5 utilize a “WBS” VIN prefix?
Starting with the E28 M5, all products from BMW Motorsport GmbH were assigned a “WBS” VIN prefix to distinguish them from the non-M BMW AG vehicles, which retained a “WBA” prefix. However, the first 26 left-hand drive ECE examples of the E28 M5 were produced with the regular WBA prefix.
Why do most sources list the total production of North American-spec M5s at 1,370 instead of 1,340?
Most sources (including BMW AG itself) list the total production of North American-spec E28 M5s (USA and Canada combined) at 1,370 units. However, this figure does not consider a major flaw in the BMW production database that lists 30 additional VINs which do not, in fact, actually exist. Thus, the accurate figure is 1,340.
Of the 1,340 North American-spec E28 M5s, how many were built to Canadian specification?
A total of 102 E28 M5s were built to Canadian specification, while the remaining 1,238 were built to U.S. specs. Aside from minor differences in instrumentation (imperial versus metric), U.S. and Canadian E28 M5s are identical.

What makes the M88/S38 engine unique?
The M88 and S38 engines are evolutions of the 24-valve inline-six developed for the mid-engine M1 supercar. Like that engine, both the M88 and S38 share a displacement of 3,453cc (via a bore of 93.4mm and a stroke of 84mm), and both have a four-valve crossflow cylinder head (with 37mm inlet valves and 32mm exhaust valves) designed for better breathing at high rpm. However, for their application in the E28 M5, the M88 and S38 have unique pistons and connecting rods, as well as more advanced Bosch Motronic fuel injection/engine management. To save costs, both engines utilize the standard steel M30 crankshaft and wet-sump lubrication system. Many other smaller items, such as the ignition system, are shared with the regular 5 Series as well.
How do the M88 and S38 engines differ?
The M88 is the non-catalyst version of the S38 engine. With a 10.5:1 compression ratio, 264-degree camshafts, and a single-row timing chain, it is identical to the one found in the non-catalyst versions of the E24 M635CSi coupe. Power is rated at 286 hp (DIN) at 6,500 rpm with 251 lb/ft of torque at 4,500 rpm. The M88 can be identified by the BMW Roundel and only the words “M Power” on its valve cover.

The S38 s the “clean” version of the M88 motor, introduced to allow E28 M5s sold in the United States and Canada to comply with North American emissions regulations. It utilizes a duplex (double-row) timing chain, 248-degree camshafts, and features a lower 9.8:1 compression designed to work with catalytic converters. This reduced the horsepower to 256 hp (SAE) or 260 hp (DIN) at 6,500 rpm and torque to 243 lb/ft at 4,500 rpm. The S38 can be identified by the words “BMW M Power” on its valve cover.
What kind of gearbox does the E28 M5 have?
All E28 M5s have the Getrag 280/5 five-speed manual gearbox. Gear ratios are as follows: 3.51 (1), 2.08 (2), 1.35 (3), 1.00 (4), .81 (5). A 3.73:1 final drive is fitted to all but the North American E28 M5, which uses a 3.91:1 rear end. All have limited slip differentials with a maximum locking of 25 percent.

How is the suspension of the E28 M5 different from that of a standard 5 Series?
All M5s utilize the MacPherson strut/semi-trailing arm chassis design common to all E28 5 Series, though the suspension geometry has been altered and many components have been upgraded by BMW Motorsport in various ways, depending on the market and production date.
Up front, European-spec models produced before October of 1986 feature unique Bilstein shock inserts (shared only with the European-spec M635CSi) mounted to standard E28 struts, plus a 21mm anti-roll bar. However, beginning in October of 1986, the front shocks were updated to a different iteration from Boge (also specific to the M5) and the anti-roll bar was enlarged to 25mm. In the rear, European-spec M5 built before February of 1986 retained standard E28 components, including the springs, shocks (Bilstein) and a 14mm anti-roll bar. However, the M5 received unique rear springs beginning with February 1986 production, followed eight months later by a switch to Boge rear shocks and a larger 18mm rear anti-roll bar.

The chassis of the North American-spec E28 M5 is different from the European-spec version in a number of ways. Its front suspension contains standard springs (shared with the North American-spec E28 535i/535is and European-spec E28 M535i/E24 635CSi) and shocks (shared with the North American-spec E24 635CSi), though it did receive the 25mm anti-roll bar used on later European-spec M5s. The M5-specific rear springs and 18mm rear anti-roll bar are identical to those of later European-spec M5s. However, the North American model is further equipped with an automatic load-leveling system that is unique to this version within the entire E28 range.
What size brakes does the E28 M5 have?
The E28 M5 has enlarged vented front rotors that measure 11.8-inches (300mm) in diameter. These utilize four-piston calipers. The solid rear rotors are the same as those fitted to an E28 535i or M535i, measuring 11.2-inches (284mm) in diameter. ABS is standard.

What wheels and tires were offered on the E28 M5?
Two different factory alloy wheels were available for the E28 M5. The majority of European-spec E28 M5s were equipped with metric-sized forged alloy wheels also used on some E23 7 Series and E24 6 Series models. These measure 195mm x 390mm and are shod with 220/55VR390 tires.

Later in production, the E28 M5 was also offered with7.5x16-inch cross-spoke alloy wheels carrying 225/50VR16 tires, usually Pirelli P700s. These wheels were introduced as an option on left-hand drive European-spec M5s starting in 9/86 (1987 model year), and were made standard on right-hand drive E28 M5s at the same time (though they were also offered as an option on UK-market M5s built before 9/86). All North American-spec E28 M5s, as well as those produced for South Africa, received these wheels as standard equipment.

What distinguishes the exterior of a European-spec E28 M5 from that of a normal 5 Series?
Because the intention of BMW Motorsport was to hide the performance capabilities of the M5 within a standard-looking 5 Series body, there are few external items that differentiate the European-spec E28 M5 from any other E28 sedan. The only body panel that is unique is the black plastic front airdam, included to reduce front end lift at high speeds. There is also an M5-specific aerodynamic engine compartment undertray, body-color rear-view mirror housings and a pair of “M5” badges, one on the grille and another on the trunk-lid, though these could be omitted upon request (which was common).

Two different alloy wheels were offered on the E28 M5: A metric-sized version made of forged alloy (exclusive to the M5 within the E28 series but also offered on the E24 6 Series and E23 7 Series), as well as a unique 7.5x16-inch cross-spoke wheel (introduced for the 1987 model year) that also included body-color fender lip extensions. Shadowline (dechromed) exterior trim for the window surrounds, bumpers and side moldings was optional beginning with 4/86 production.
In most European markets, the M-Technic aerodynamic package (as fitted as standard to the E28 M535i) was offered as an option. This consisted of body-color extensions with ribbed trim (front bumper and lower airdam, side valance panels, rear bumper and lower diffuser), the M-technic rear spoiler and dechromed side moldings. This option could be ordered with or without Shadowline trim and was commonly (but not always) paired with the 16-inch cross-spoke alloy wheels and body-color fender lip extensions.

How is the interior of an E28 M5 different from that of a regular 5 Series?
Though identical in basic design and layout to that of any E28 5 Series, the interior of the E28 M5 is fitted with a few special items. All examples have a three-spoke M-Technic steering wheel also used in other BMW models. Most are also equipped with sport front seats, though a few were fitted with the standard “comfort” versions by request and some even had genuine Recaro front seats in place of the BMW items. In some markets, both the front and rear seats include an M tri-color stripe attached to a metal tag. On the earliest cars, the leather shift knob is topped with only an “M” logo. This was soon changed to a version with both the standard shift pattern and the tri-color M stripe. The instrument cluster contains a unique 280 kph/170 mph speedometer and a special tachometer with the M logo instead of an economy meter. A black headliner is exclusive to the M5 within the E28 range and later examples also have special door sill plates with the “M5” logo. Finally, the trunk of the E28 M5 is unique for four reasons. First, it contains the battery in a special right-side compartment, secured by one of two different covers, depending on the production date. Second, it is lined with a plush carpet. Third, with the exception of the earliest examples, the lining on the inside of the trunk lid is black instead of the usual light grey. Finally, there is a special cargo net to secure loose objectrs, though this also does not appear to have been fitted to the earliest cars.
What features were optional on the European-spec E28 M5?
Because the E28 M5 was assembled largely by hand at the BMW Motorsport facility, European customers could not only choose from the entire range of normal E28 options but also request more specialized features like hand-stitched complete leather interiors and/or integrated electronics such as phones, faxes, and minibars. Thus, depending on the market and production date, the E28 M5 could be very sparsely equipped or extremely luxurious. However, every E28 M5 features power front windows, power mirrors, central locking, and the Check Control vehicle function monitoring system. Options varied from market to market but generally included metallic paint, Shadowline (dechromed) exterior trim, headlight washer/wipers, leather upholstery (in various grades), air conditioning, the on-board computer II, power front seats, heated front seats, power sunroof, rear window sunshade, rear headrests and various audio systems.
How is a North American-spec E28 M5 cosmetically different from a Euro-spec E28 M5?
The North American-spec E28 M5 uses the same government-mandated sealed-beam headlights (all four of the same diameter) and 5-mph bumpers with integrated side marker lights as all U.S. and Canadian versions of the E28 5 Series. However, the M5 adds a special front airdam designed specifically for the North American front bumper as well as the M-Technic rear spoiler fitted as an option to some European-spec examples. Though these items are not unique to this model (both are also found on the E28 535is), the M5 can further be identified by its Shadowline trim, “M5” grille and trunk-lid badges plus the 16-inch cross-spoke alloy wheels.

How is the interior of the North American E28 M5 different from that of the European version?
Unlike the wide variation of color, trim and equipment found in European-spec E28 M5s, all North Americans-spec interiors have Black or Natur leather sport seats, with additonal hide on the seats, center console, glovebox door and door pulls. In addition, all have the M tri-color seat stripes (front and rear) and “M5” door sill plates, while the carpeted trunk always features the black lid lining, cargo net, later-style battery box enclosure and left-side storage compartment. Standard equipment includes air conditioning, power seats, power sunroof, cruise control and an eight-speaker am/fm cassette stereo system. Heated front seats were the only factory option (standard in Canada)

Special Versions
Were there any special versions of the E28 M5?
There were no special editions of the German-built E28 M5. However, a limited run (96 cars) of M5s was assembled in South Africa exclusively for that market.
What distinguishes the South African E28 M5 from the German-built version?
The 96 right-hand drive E28 M5s produced for the South African market were assembled at the Rosslyn, South Africa factory using German-supplied Complete Knock Down (CKD) kits. The mechancal items are thus identical to those of the European-spec E28 M5.

Cosmeticaly, however, the South African E28 M5 is somewhat unique. All are equipped with the M-Technic body panels that could be ordered as an option in some European markets, as well as Shadowline trim and the 7.5x16-inch cross spoke alloy wheels. However the South African E28 M5s do not include the body-color fender lip extensions found on the German-built cars, nor were they offered with headlight washer/wipers. Also, because the South African E28 M5s were painted in the local paint shop, exterior colors were limited to five choices: Henna Red, Ice White, Cirrus Blue metallic, Delphin Gray metallic and Diamond Black metallic.
On the inside, all South African E28 M5s have essentially every normal 5 Series luxury item as standard, the only optional extra being a power sunroof. Unique to the South African version is a complete “Highline” Nappa leather interior normally offered only in E24 6 Series and E23 7 Series models. Available in four color choices (Lotus White, Natur, Midsilver and Indigo), the interior includes Nappa leather on the seats, door panels, center console, glovebox door, headliner, sun visors, upper door trim and dashboard. (NOTE: The passenger-side dashboard does not include the storage tray found on all German-built E28s.) The M tri-color insignias remain present on the front and rear seats. Finally, South African-spec models are not equipped with the black inner trunk lid liner used on all but the earliest German-built E28 M5s, though they do utilize the black trunk carpeting.
1985 BMW M5 Specifications