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Drivetrain

How is the S38 engine in the E34 M5 different from the version used in the E28 M5?
The early E34 M5 uses an evolution of the 24-valve inline-six found in the E28 M5 and E24 M635CSi/M6. Designated S38 B36, the engine technically remains a 3.5-liter, with a bore of 93.4mm (same as the previous engine) and a stroke of 86mm (up 2mm on the early S38) for a total capacity of 3535cc (up from 3453cc). The added stroke is due to a new forged steel crankshaft, though the camshafts were also changed. Compression is up slightly (10:1 versus 9.8:1). Further enhancements include:
-An electronically-controlled butterfly valve in the inlet manifold to provide better low-rpm and mid-range power
-Bosch Motronic fuel injection for precise metering of the air/fuel mixture
-Improved flywheel
-Equal length stainless steel headers
-Three way ceramic catalysts (similar to those used on the M70 V12 engine)

The S38 B36 is rated at 315 hp (DIN) or 310 hp (SAE) at 6,900 rpm and 266 lb/ft of torque at 4,750 rpm. Like the earlier S38 B35, it carries the "BMW M Power" inscription on its cam cover but the design of almost every component is different.

Unlike the engine used in the E28 M5, the S38 B36 engine in the E34 M5 was designed to meet all worldwide emission standards from the start. Therefore, the engines used in North American- and South African-spec E34 M5s are essentially the same as those used in the European-spec models.

How is the 3.8-liter M5 engine (S38 B38) different from the 3.6-liter version (S38 B36)?
The final evolution of the S38 powerplant, the S38 B38, was used in later versions of the E34 M5, none of which were sold in North America. In this application, the bore was increased (to 94.6mm) and the stroke lengthened (to 90mm), raising the displacement to 3,795cc. Though the added capacity makes the S38 B38 the largest six-cylinder production BMW engine of the modern era, it represents only a portion of the major revisions developed by BMW Motorsport at this time. Others include:
-Larger intake and exhaust valves
-Lighter pistons
-Shorter conrods
-Increased compression to 10.5:1
-Bosch Motronic 3.3 engine management system
-Distributorless ignition with six coils
-Redesigned intake and exhaust manifolds
-Revised throttle butterfly linked to Motronic engine control
-Dual-mass flywheel with harmonic balancer
-Metal catalysts for reduced backpressure and better heat conduction

The S38 B38 is normally rated at 340 hp (ECE)/347 hp (DIN) at 6,900 rpm and 295 lb/ft of torque at 4,750 rpm. However, a cleaner version was developed for Austria and Switzerland, rated at 334 hp (ECE) and later 327 hp (ECE). The S38 B38 can be identified by its grey (instead of black) cam cover surround.

What kind of gearbox does the E34 M5 have?
All M5s built before May, 1994 have a Getrag 280/5 five-speed manual gearbox with the following ratios: 3.51 (1), 2.08 (2), 1.35 (3), 1.00 (4), 0.81 (5). These cars have a 3.91:1 final drive, with the exception of North American-spec E34 M5s built to 1992 and 1993 specification which have a taller 3.73:1 final drive for better fuel economy.

As of May, 1994 production, the five-speed was replaced with a Getrag Type D six-speed manual box with the following ratios: 4.23 (1), 2.52 (2), 1.66 (3), 1.22 (4), 1.00 (5), 0.83 (6). A taller 3.23:1 final drive was fitted at this time.

All E34 M5s have a standard limited slip differential with a maximum locking of 25 percent.



Chassis

How is the E34 M5's suspension different from the standard E34 5 Series?
The E34 M5’s chassis is based on the MacPherson strut/semi-trailing arm design of the normal E34 5 Series but incorporates the following changes from BMW Motorsport:
-20mm reduction in ride height
-25 percent firmer spring rates
-Firmer shock valving all around and self-leveling in the rear
-Thicker antiroll bars (25mm vs. 23mm in the front, 18mm vs. 15mm in the rear)
-Adjustable rear toe-in

All 3.8-liter M5s are further fitted with the Adaptive M Suspension, an M-tuned version of the Electronic Damping Control system that was introduced in the E32 7 Series. This system electronically chooses the optimum shock rates based on sensors that gather road speed, steering input, acceleration/deceleration loads and lateral body movements. Furthermore, M5s equipped with the Nurburgring package (standard from May, 1994) have a control switch on the dashboard to lock the Adaptive M Suspension into the firmest setting during aggressive driving.

How is the E34 M5's steering system different from the standard E34 5 Series?
Like all E34 5 Series, the E34 M5 uses a recirculating ball steering design, but the overall ratio is reduced from 16.2:1 to 15.6:1.

Two types of power assistance were offered: An engine-speed sensitive system was fitted to all European-spec 3.6-liter M5s and on North American models built before September, 1991. A vehicle-speed sensitive system developed by ZF and called Servotronic was available on European-spec 3.8-liter models as either a stand-alone option or as part of the optional Nurburgring Package. However, Servotronic was not included with the Nurburgring Package after it became standard equipment in May of 1994, but continued to be available as an individual option. Servotronic was also fitted as standard to all North American-spec M5s built after September, 1991 (i.e. 1992 and 1993 model years).

What is the Nurburgring Package?
In addition to the standard Adaptive M Suspension fitted to all 3.8-liter M5s, the Nurburgring Package could be added as an extra cost option. This consisted of ZF Servotronic (vehicle-speed sensitive) power steering, a 19mm rear anti-roll bar, wider 255/40ZR17 rear tires on 9x17-inch alloy wheels (already standard on the Touring) and a control switch for the adjustable shocks that allowed them to be locked in the firmest position. This package became standard on all M5s as of May, 1994 production, with the exception of the Servotronic steering which became a separate option at this time.

What size brakes does the E34 M5 have?
All M5s built before May, 1994 have upgraded vented front disc brakes measuring 12.4-inches. The rear rotors measure 11.8-inches in diameter and are vented as of 10/89 production. The May, 1994 update brought even larger front and rear brakes (now 13.6-inches and 12.8-inches, respectively) and the front rotors were changed to a two-piece “floating” design for better heat dissipation.

What are the factory wheel and tire sizes for the E34 M5?
There are two factory 17-inch wheels for the E34 M5, M System I and M System II. Both are a two-piece wheel with a forged five-spoke center and a cast rim covered by an outer cover. The only difference is the design of the outer cover, "turbine" for the M System I and "throwing star" for the M System II. This outer cover is interchangeable between the two M System wheels, making updating form the earlier style to the later style an easy (and therefore common) procedure.

The 3.6-liter M5 is equipped with 235/45ZR17 tires on 8x17-inch M System I wheels. However, for the 1993 model year, North American-spec M5s use the M System II design in the same size. In addition, wider 255/40ZR17 rear tires on 9x17-inch M System I wheels were available as an option in some markets (not North America).

All 3.8-liter M5 sedans built before May, 1994 are equipped with 235/45ZR17 tires on 8x17-inch M System II wheels. Sedans equipped with the optional Nurburgring Package and all Tourings use wider 255/40ZR17 rear tires on 9x17-inch M System II wheels.

All M5s built after May, 1994 have 245/45ZR18 tires on all four corners with staggered M Parallel Spoke wheels measuring 8x18-inches in the front and 9x18-inches in the rear. Note: Though nearly identical in style to the 18-inch M Parallel Spoke wheels later used on the E38 7 Series, the E34 M5 wheels have a matte silver finish and a unique offset.



Cosmetics

How is the E34 M5’s exterior different from that of a normal 5 Series?
An E34 M5 is most easily distinguished from a normal 5 Series by its unique lower body panels that include a front airdam, side valances and rear diffuser. These are painted in a contrasting Diamond Black metallic (181), Sebring Grey metallic (229) or Granite Silver metallic (237), depending on the car’s exterior color and production date. In addition, the E34 M5 has large-diameter twin exhaust pipes and “M5” grille and decklid badges (only the former on M5s built after May, 1994). Like the previous E28 M5, these could be deleted upon request. Dechromed window trim (known as Shadowline) was optional on the E34 M5 in most markets, as was a body-color rear decklid spoiler. Starting with the production of the 3.8-liter model, the E34 M5 could be ordered (in most markets) with aerodynamic M rear-view mirrors (also fitted to all North American-spec E34 M5s for the 1993 model year). All E34 M5 sedans have a black plastic panel that fills in the gap between the taillights and the license plate. Though this panel was only fitted to M5 sedans, this same area on the M5 Touring is covered in an exclusive textured black paint (instead of the normal body-color).

The E34 M5 was also the only regular production 5 Series to be fitted from the factory with 17-inch M alloy wheels in either a “turbine” style known as M System I (all 3.6-liter models and North American-spec cars up to 9/92) or a “throwing star” design known as M System II (all 3.8-liter cars up to 5/94 and North American-spec after 9/92). The final six-speed 3.8-liter M5s (from 5/94) use an 18-inch M Parallel Spoke design, also essentially unique to the M5 within the E34 range.

How is the North American-spec E34 M5 cosmetically different from the European-spec version?
Aside from government-mandated safety features such as bumper-mounted side marker lights, North American cars are visually very similar to their Euro-market counterparts. The sole exception are 1993 models (built from 09/92-03/93). These have the exterior appearance of the European-spec 3.8-liter M5, but retain the 3.6-liter engine and chassis.

How is the South African version of the E34 M5 cosmetically different from the German-built version?
The South African-built M5s are cosmetically identical to the European-spec cars. However, like the South African-spec E28 M5s, their bodies were painted at BMW's Rosslyn factory, thus exterior paint choices may have been limited.

How is the exterior of the 3.8-liter M5 cosmetically different from that of the 3.6-liter model?
The wheels are the main exterior differentiator between a 3.6-liter E34 M5 and a later 3.8-liter model. The European-spec 3.6-liter M5s were all equipped with the M System I (“turbine”) wheel design, while the 3.8 utilized the M system II (“throwing star”) version until April, 1994. At that point, all M5s were upgraded to the 18-inch M Parallel Spoke wheels. (Note: North American-spec 1993 M5s use the later M System II wheel even though they are powered by the earlier 3.6-liter engine.)

In addition, the contrasting color of the lower aerodynamic body panels differed between the 3.6-liter and 3.8-liter M5 models. On the 3.6-liter examples ,these were painted either Diamond Black metallic (181) or Sebring Grey metallic (229). This changed with the 3.8-liter version to a choice of either Diamond Black metallic (181) or Granite Silver metallic (237). (Note: the change from Sebring Grey to Granite Silver also applies to the 1993 North American-spec E34 M5, which retained the 3.6-liter motor.)

What distinguishes the interior of the E34 M5 from that of a normal E34 5 Series?
Though the basic architecture of the interior is identical to that of any E34 5 Series, the M5 interior does have a few unique items: The unique instrument cluster contains red needles, an oil temperature gauge under the tachometer (instead of an economy gauge) and an M logo between the speedometer and tachometer. Like the E28 M5, there are "M5" trim plates on all four door sills (in one of two versions, depending upon the production date) and a fully-carpeted trunk with a storage compartment on the left side.

All E34 M5s are equipped with sport front seats, identical in shape and adjustment to those fitted as an option to other E34 5 Series models. Power controls were either standard or optional, depending upon the year and market. On European-spec M5s, the seats could be upholstered in a unique M cloth with leather boolsters on 3.6-lier models or a different M cloth with Amaretta suede bolsters on 3.8-liter models, as well as optional leather. Also, all E34 M5s built before September, 1990 have a fixed rear center console that effectively makes them four-seaters. This console became optional in most markets starting with September, 1990 production.

There were five different factory steering wheels available on the E34 M5, depending on the market and production date. Most 3.6-liter models and some early 3.8-liter cars have the three-spoke M-Technic II steering wheel without an airbag but with the M logo on the third spoke. Standard on U.S.-spec M5s and optional in most other markets (including Canada) was the regular airbag-equipped four-spoke BMW wheel. Starting with September, 1992 production, this wheel was upgraded to include the M tri-color stitching on the rim. Beginning with the 1994 model year (09/93 production), E34 M5s could be fitted with either an M-enhanced version of the four-spoke airbag wheel, now including a thicker rim with thumb grips and a revised center pad, or a new non-M three-spoke wheel with an integrated Euro-sized airbag. A leather-wrapped shift knob with an illuminated shift pattern and the M tri-color stripe was fitted as standard to all E34 M5s. Also, the area around the shift lever is unique in that it is recessed for extra storage.

Finally, all E34 M5s have a check control vehicle monitoring system integrated into the instrument cluster and the fourth-generation BMW on-board computer.

What are all the ways that the interior of U.S. and Canadian E34 M5s differ?
All North American E34 M5s are mechanically identical and share the same exterior appearance, with the exception of standard headlight washers on Canadian-spec cars. This feature aside, it is only on the inside that U.S. and Canadian cars can be distinguished from each other. The following are all the ways the two models differ, aside from having metric (Canada) or non-metric (U.S.) instrumentation:

U.S Specification:
Leather trim: Standard on seats only
Fixed rear console: Standard before 09/90 production, then deleted
Heated seats: Optional
Driver’s airbag with knee bolster: Standard
Driver’s three-position seat memory and power steering column adjustment: Not available

Canadian Specification:
Leather trim: Standard on seats only, optional Extended trim with leather on center console, door pulls, glovebox door
Fixed rear console: Standard before 09/90 production, optional after
Heated seats: Standard
Driver’s side airbag with knee bolster: Optional
Driver’s three-position seat memory and power steering column adjustment: Optional

How does the interior of the South African E34 M5 differ from that of the German-built model?
There were no significant differences between the interior of the German-built E34 M5 and those assembled in South Africa, although the level of standard equipment was generally higher on South African models.

How is the 3.8-liter E34 M5's interior different from that of the 3.6-liter version?
The interior of the 3.8-liter E34 M5 is essentially identical to the one found in 3.6-liter models. The main exception concerns the standard cloth upholstery. Early (3.6-liter) E34 M5s that are not equipped with optional leather upholstery have M cloth seats and door panels with leather on the outer bolsters, while the later (3.8-liter) cars have a different type of M cloth on the center part of the seats and door panels with a suede-like Amaretta material on the bolsters.

Also, 3.8-liter M5s have more pronounced door sill plates with the “M5” logo in a style similar to that of the E36 M3. (Note: North American-spec M5s built after 01/92 also have this design.)

What features were optional on the E34 M5?
Like most other M models, the level of standard and optional equipment for the E34 M5 varies significantly from year to year and market to market. Major exterior options (standard in some markets) include power sunroof, metallic paint, heated headlight washers, Shadowline (dechromed) trim and a body-color rear spoiler. Like the E28 M5, the E34 M5's hand-built nature allowed even more variation on the interior. All regular E34 options were available, as well as various special types of upholstery, dash and console trims, and luxury items such as upgraded audio systems, phones, fax machines and televisions.

These special-order items were generally not availble in the North American market, where the E34 M5's option list was confined to heated front seats (standard in Canada), a CD changer, integrated cellular phone and remote locking with alarm (standard from 9/91 production) . One further rare option was the "Four-Seasons" glass moonroof, discontinued as of September, 1990. In addition, Canadian cars could further be fitted with a three-position memory for the driver's power seat and power steering column, extended leather upholstery and the fixed rear center console (standard on all North American cars built before September, 1990).

What types of leather trim were available on the E34 M5?
There were three types of leather trim offered as part of the normal upholstery options for the E34 M5: The most basic included leather only on the seats. This was the only type available on U.S.-spec M5s, where it was standard. In most other markets (including Canada), the interior could be upgraded to "extended leather", which added hide on the center console, door pulls, and glovebox door. Finally, the top-level "complete leather" interior further added leather to the upper dashboard (including instrument cluster surround), A-pillars, upper door panels, sunvisors and rear parcel shelf. Please note that not all upholstery colors were offered with every leather type. See "Color and Upholstery Selections" below.