Count me in as a 5 series lover. I have owned 3, an e39 540, and e60 M5 and presently 550i (Ok, I know those models barely count!
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I do love the e28 M5. They are so rare, here is some information:
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 built?
Unlike the normal 5 Series models, M5s were hand-assembled at the BMW Motorsport facility in Garching, a suburb of Munich. Bodies were pressed at the normal Dingolfing factory, then sent to Garching where they were mated with the engine and interior trim. The only exceptions were the South African-spec cars, assembled at BMW's Rosslyn, South Africa factory from German-supplied Complete Knock Down (CKD) kits.
Where was the E28 M5 first introduced?
The M5 debuted at the 1985 Amsterdam Motor Show.
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 (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.
Drivetrain
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 have a four-valve crossflow cylinder head (with 37mm inlet valves and 32mm exhaust valves) designed for better breathing at high rpm and a pair of 264-degree camshafts. They also share a displacement of 3,453cc via a bore of 93.4mm and a stroke of 84mm. However, for their application in the E28 M5, the M88 and S38 have unique pistons and connecting rods, as well as a more advanced Bosch ML-Jetronic fuel injection system. 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 and a single-row timing chain, it is identical to the one found in the 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 inscription on its cam cover: the propeller Roundel plus the words “BMW” or “M Power.”
The S38 is the “clean” version of the engine, exclusively available in the E28 M5 in North America. It utilizes a duplex (double-row) timing chain and 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 has the inscription “BMW M Power” on its cam cover but no Roundel.
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.
Chassis
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.