CHASSIS AND SUSPENSION
The chassis of the E92 M3 is based on the chassis of the series model E92. All modifications are described in this section.
Scheme 27
| Designation | E92 M3 | Series E92 335i |
|---|---|---|
| Tire type/Wheel rim type/Rim offset [mm] | 245-40 ZR 18/8.5Jx18/IS29 | 225-45 WR 17 RSC/8Jx17/IS34 |
| Tire radius [mm] | 305 | 295 |
| Wheelbase [mm] | 2761 | 2760 |
| Track width [mm] | 1538 | 1500 |
| Total toe | 16' | 14' |
| Toe differential angle | 2° 14' | 1° 40' |
| Camber | 1° | 18' |
| Kingpin inclination | 15° 2' | 14° 7' |
| Kingpin offset [mm] | 8.4 | 5.1 |
| Trail [mm] | 29.4 | 20.3 |
| Trail angle | 7° 8' | 7° 5' |
CHASSIS AND SUSPENSION SPECIFICATION CHART
Scheme 28
Scheme 29
Wheel suspension components
| Index | Explanation |
|---|---|
| 1 | Rubber mount for tension strut |
| 2 | Tension strut |
| 3 | Swivel bearing |
| 4 | Wheel hub |
| 5 | Wishbone |
| 6 | Front axle carrier |
INDEX EXPLANATION REFERENCE CHART
Front Axle Carrier
The front axle carrier is an aluminum alloy construction. In order to ensure optimum strength and torsional rigidity, a high-pressure forming technique has been used to manufacture certain sections.
Aluminum has been chosen for its lightweight and strength properties. The components of the front axle are joined together by an aluminum welding process.
Scheme 30
Swivel Bearing
The 'M' swivel bearing is completely new. The bearing is made from an aluminum cast alloy, which reduces the weight by 500 grams.
The following changes have been made to the front wheel carrier
Scheme 31
Scheme 32
- Adjusted dimensions for the larger 'M' wheel.
- As described below, the method by which the spring strut is clamped into the swivel bearing has been changed.
- The geometric fixing points for the wishbone, tension strut and steering track rod have been selected to ensure optimum sports vehicle kinematics.
- Modified mounting position for the larger brake caliper. INDEX EXPLANATION REFERENCE CHART Index Explanation 1 Clamp connection of the spring strut support 2 Attachment points for the tension strut, wishbone and steering track rod 3 Brake caliper mounting
Spring Strut
The front steel suspension spring has a 95 mm compression and 100 mm rebound travel.
A new spring concept supports lateral chassis stability. Depending on the vehicle weight (equipment), modified spring types are used.
Scheme 33
| Index | Explanation |
|---|---|
| 1 | Retaining nut, shock absorber to support bearing |
| 2 | Dowel pin, support bearing to body |
| 3 | Mounting fixture, support bearing to body |
| 4 | Joint seat |
| 5 | Support bearing |
| 6 | Upper spring seat |
| 7 | Support disc |
| 8 | Additional damper/spring |
| 9 | Gaiter |
| 10 | Lower spring seat |
| 11 | Spring strut |
INDEX EXPLANATION REFERENCE CHART
Scheme 34
Legend for graphic on previous page
| Index | Explanation |
|---|---|
| A | Spring strut support in the E92 series model |
| 1 | Vertical force (Z-axis) |
| 2 | Upper and lower limit for supporting lateral and longitudinal force (X and Y axis) |
| 3 | Clamp height 52 mm parallel fit |
| 4 | Parallel contact face |
| A | Spring strut support in the E93 M3 |
| 1 | Vertical force (Z-axis) |
| 2 | Upper and lower limit for supporting lateral and longitudinal force (X and Y axis) |
| 3 | Clamp height 76 mm with parallel upper and conical lower fit |
| 4 | Upper cylindrical and lower conical contact face |
INDEX EXPLANATION REFERENCE CHART
As shown in the diagram, the clamp height has been increased on the Z-axis from 52 mm on the series E92 (left) to 76 mm on the E92 M3 (right).
The front spring strut now has an additional support. The wheel carrier has also been modified to compensate for the increased drive and dynamic forces.
The lower contact face of the spring strut in the E92 M3 has a cone, which is positioned firmly in the wheel carrier. In the series E92, however, the front spring strut has a parallel construction and is only held in place by the clamping force.
This design change and the increased clamp height accommodate the increased reaction forces of the spring strut and increase the overall stability of the wheel suspension.
During assembly, the M3 spring strut is pulled into the lower cone using a new special tool.
Note. Follow the new installation and removal process according to the service repair manual.
Tension Strut
The tension strut is similar to that used in the series E92, but features an 'M'-specific harder rubber mount.
Scheme 35
Wishbone
The M control arm is completely new and is connected to the axle carrier and wheel carrier by two ball joints. It is manufactured out of forged aluminum alloy.
Scheme 36
Wheel Bearing Unit
The M3 wheel bearing unit is identical to the E60 M5 wheel bearing unit. It has three dowel pins for the brake disc.
Scheme 37
Front Anti-roll Bar
The weight-optimized front anti-roll bar was adapted for the M3 and has a special rubber bearing material for more direct response. The hinged brackets are made out of an aluminum alloy (series E92 steel).
Scheme 38
STEERING
The design of the rack-and-pinion steering system is the same as the series E92. The average variable overall ratio is 12.5 and hence sports-oriented (16 in the series E92).
In the M3, the steering force support is controlled by the MSS60 via the Servotronic valve. A speed dependent characteristic curve is stored in the MSS60 for this purpose. With the MDrive menu option, a second and even more sports oriented characteristic curve can be activated.
The steering oil is guided through a steering oil cooler before it returns to the oil reservoir.
The E92 M3 is not available with active steering.
Scheme 39
| Index | Explanation |
|---|---|
| 1 | Steering oil header tank |
| 2 | Steering oil hydraulic pump |
| 3 | Steering transmission housing |
| 4 | Steering oil cooler |
| 5 | Steering wheel spindle |
INDEX EXPLANATION REFERENCE CHART
Rear Axle Carrier
The rear axle carrier is constructed from steel sections which are welded together. All mounting points for the rear axle and suspension components are formed or attached to the axle carrier making it an integral component.
Nearly all components of the rear chassis have been revised, the aim is to achieve optimum sports vehicle kinematics, chassis stability and a more precise and direct response, with a simultaneous reduction in weight.
This has been achieved by the careful selection of materials for the axle components and bearings, and through a modification of the axle geometry.
Scheme 40
| Designation | E92 M3 | Series E92 335i |
|---|---|---|
| Tire type/Wheel rim type/Rim offset [mm] | 265-40 ZR 18/9.5Jx18/IS23 | 225-45 WR 17 RSC/8Jx17/IS34 |
| Tire radius [mm] | 311 | 295 |
| Wheelbase [mm] | 2761 | 2760 |
| Track width [mm] | 1539 | 1513 |
| Total toe | 10' | 18' |
| Driving axis angle | 0° | 0° |
| Camber | 1° 45' | 1° 30' |
REAR AXLE SPECIFICATION CHART
Scheme 41
| Index | Explanation |
|---|---|
| 1 | Wheel carrier |
| 2 | Toe struts |
| 3 | Connections from control arm to rear axle carrier |
| 4 | Camber struts |
| 5 | Wishbone |
| 6 | Shock absorber |
| 7 | Rear axle carrier |
| 8 | Traction strut with semi-trailing arm below it |
INDEX EXPLANATION REFERENCE CHART
Wheel Carrier
The attachment points for toe, camber, wishbone, longitudinal and traction struts have been positioned specifically for the 'M' model.
Its overall dimensions allow for the larger M wheel to be fitted. The 'M' wheel carrier is fitted with a modified rubber mount connecting to the semi-trailing arm and a ball joint for the camber strut.
Toe Struts
The new 'M' toe strut is forged from Aluminum. It is one-piece and has two integrated ball joints.
Camber Struts
The 'M' camber strut is a new lightweight component forged from Aluminum. Its design reduces the unsprung mass of the vehicle.
The new 'M' wishbone is forged from aluminum and has a modified integrated ball joint and a rubber mount.
Control Strut
The semi-trailing arm is the only rear suspension strut that is taken from the series E92. It is connected further inwards on the rear axle carrier, only the rubber mount is new.
Traction Strut
The geometry of the forged aluminum 'M' traction strut has been revised. It now has a new integrated rubber mount for the wheel carrier. The ball joint for the rear axle carrier has been taken from the series E92.
Rear Shock Absorbers
New 'M' specific rear aluminum dampers are fitted to the M3. Electronic damper control - continuous (EDC-K), is available as an option.
The integrated lower damper rubber mount has a support sleeve that improves the rigidity and stability between the damper and the camber strut.
Scheme 42
Overview of rear axle struts
| Index | Explanation |
|---|---|
| 1 | Wheel carrier |
| 2 | Toe strut |
| 3 | Camber strut |
| 4 | Control strut |
| 5 | Wishbone |
| 6 | Traction strut |
INDEX EXPLANATION REFERENCE CHART
Scheme 43
EDC-K is available for the first time in the E92 M3. EDC-K is an option and is based on the EDC-K in the E65.
Both dampers of one axis are always activated in parallel. The valve is installed internally in the damper in the damper oil system.
The driver can choose between three settings, the controlled programs "Comfort" and "Normal", or the uncontrolled fixed setting "Sport".
The program is selected using the EDC-K button on the center console or preset via the MDrive menu and activated using the M button on the steering wheel.
The input signals come from two vertical acceleration sensors in the front wheel arches and a third sensor in the rear right-hand wheel arch.
The steering column switch cluster sends the steering angle to the F-CAN. This is transmitted together with the wheel speeds from the DSC to the PT-CAN and evaluated in the EDC-K control unit.
The longitudinal, lateral and vertical accelerations calculated as a result are used as a basis for regulation.
The EDC-K button signal enters the junction box and is transmitted to the EDC-K on the PT-CAN.
Scheme 44
| Index | Explanation |
|---|---|
| A | Damping force rebound phase (above) and compression phase (below) |
| B | Damper piston speed |
INDEX EXPLANATION REFERENCE CHART
The compression phase, and in particular the rebound phase, of the shock absorbers can be adjusted by the EDC-K depending on the input signals in a smooth transition from relatively comfortable to a harder sports setting.
Scheme 45
| Index | Explanation |
|---|---|
| 1 | EDC valve, front right |
| 2 | Vertical acceleration sensor, front right |
| 3 | Junction box/distribution box |
| 4 | EDC-K control unit |
| 5 | Vertical acceleration sensor, rear left |
| 6 | EDC valve, rear right |
| 7 | EDC valve, rear left |
| 8 | EDC button on center console |
| 9 | Steering column switch cluster |
| 10 | DSC control unit |
| 11 | Vertical acceleration sensor, front left |
| 12 | EDC valve, front left |
INDEX EXPLANATION REFERENCE CHART
Wheels and Tires
In the standard version, the cast 18" 'M' double spoke wheel (style 260) is available for the E92 M3, with the forged and polished 19" 'M' double-spoke wheel (style 220) available as an option. These are weight-optimized M3 light alloy wheels.
The tires are also specifically selected for the M3. The Michelin Pilot Sport (PS2*) is currently fitted.
Wheel/tire Specification
Standard wheel
Front - Wheel: 8.5 J x 18; IS 29; EH2+
Tires: 245-40 ZR 18
Rear - Wheel: 9.5 J x 18; IS 23; EH2+
Tires: 265-40 ZR 18
Optional
Front - Wheel: 8.5 J x 19; IS 29; EH2
Tires: 245-35 ZR 19 XL
Rear - Wheel: 9.5 J x 19; IS 23; EH2
Tires: 265-35 ZR 19 XL
Scheme 46
Brakes
For the E92 M3, the M Compound brake system with perforated brake discs and three 'M'-typical brake pad wear sensors is used, with a specifically adapted operating principle and dimensions.. The diameter of the brake discs has increased compared to the E46 M3 by 35 mm at the front, and by 22 mm at the rear.
Scheme 47
Brake System Specification
| Front brake | Diameter 360 mm, thickness 30 mm, direction-specific ventilation, single-piston floating caliper (lightweight metal alloy), brake pad wear sensor right and left. |
|---|---|
| Rear brake | Diameter 350 mm, thickness 24 mm, direction-specific ventilation, internal handbrake with 185 mm diameter (similar to E60 M5), single-piston floating caliper (cast metal alloy), brake pad wear sensor on right. |
BRAKE SYSTEM SPECIFICATION CHART
Dynamic Stability Control (DSC) MK60E5
The E92 M3 is equipped with the MK60E5 DSC system made by Continental Teves, which has been specifically adapted to its driving dynamics. The "civilian" version is installed in several models including the 6-cylinder series E92 and an M-specific version is installed in the E6x M5 and M6.
The fundamental difference in both versions is the replacement of Dynamic Traction Control (DTC) with M Dynamic Mode (MDM). MDM has been adapted to suit sports car dynamism for experienced sports drivers. The permitted float angle and longitudinal slip in good environmental conditions (road, weather, etc.) are also equally high.
Furthermore, the driving-performance control (FLR), soft stop and Fading Brake Support (FBS) functions are not required in the 'M' version.
The braking readiness, "apply the footbrake and the handbrake until the discs and drums are dry" and the gradient assistant functions have been adapted appropriately.