Powertrain - Service Information (s63) BMW X6 M E71

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TECHNICAL DATA OF S63 ENGINE IN COMPARISON WITH N63 ENGINE

EXHAUST SYSTEM HOT END OF S63 WITH N63 REFERENCE CHART

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Crankcase, Cylinder Head and Valve Timing Components

The crankcase was taken from the N63.

In view of the high ignition pressures of the S63, the pistons were upgraded accordingly.

The interior structure of the crankcase ventilation system has been adapted in terms of the oil separator and control valve (similar to S85).

Cylinder Head

The cylinder head has been adapted to accommodate the higher thermal and mechanical loads, the modified turbochargers (ATL) and exhaust manifold as well as the increased transverse dynamics of the vehicle.

The following changes have been made to the cylinder heads compared to the N63

1. The S63 cylinder heads are made from a higher grade alloy
2. Adapted bolt pattern arrangement for the new exhaust manifold
3. The exhaust camshafts are new and specific to the S63

Other changes to the top of the engine include the newly designed oil filler neck and its new location as well as the redesigned thermostat housing.

Note. It is important to note that the rigidity of the engine mounts on the S63 has been adapted to M specific requirements.

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The timing components have been adopted from the N63 engine.

The following changes have been made

1. The cam timing has been adapted.
2. The exhaust camshafts are new components, specific to the S63.

Exhaust Manifold

On the N63, a single-flow, cast exhaust manifold per cylinder bank is assigned to each exhaust turbocharger (cyl. 1-4 and cyl. 5-8).

The S63 is fitted with a four-flow, air gap insulated tuned pulse exhaust manifold that connects both cylinder banks. In an ideal configuration, the exhaust gas pulses from cylinders 1/6 and 4/7 are fed to the turbocharger installed over the right bank (cyl.1-4) and the exhaust gas pulses from cylinders 2/8 and 3/5 are fed to the turbocharger installed over the left bank (cyl. 5-8).

This design creates a spacing of 360° of crankshaft angle between the two exhaust cycles within the exhaust flute that feeds each twin scroll turbocharger turbine. The effective utilization of the exhaust gas energy delivers optimum de-throttling, ideal response characteristics and minimizes turbo lag.

Corrugated pipes combined with sliding seat flanges connect the exhaust ports from both banks within the center of the manifold outer shell to compensate for thermo-mechanical expansion and contraction. (See below)

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The specially designed exhaust manifold connects each of the 8 cylinders in sequence according to the exhaust pulses in the firing order. This delivers a uniform flow of exhaust gas to the turbochargers which improves volumetric efficiency by promoting cylinder scavenging.

Every 180° of crankshaft rotation, one exhaust gas pulse is fed to each turbocharger over the entire ignition sequence (1-5-4-8-6-3-7-2).

This highly efficient charging concept achieves optimum energy transmission of the exhaust flow to the turbine blades of the turbochargers. The result is the fastest and most direct response characteristics of any turbo engine worldwide. The innovative technology is patented by BMW and therefore represents a unique selling point over the competition.

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Advantages of the Twin-scroll Turbo System

The response characteristics of the exhaust turbochargers are enhanced when compared to the N63. The S63 turbocharger turbines are fed through two separate channels within the turbine housing (highlighted red in the graphic above). Each of these channels or "scrolls" is always fed by the exhaust pulses from the same two cylinders.

The layout and cross sections of the turbine impeller and compressor wheels have been correspondingly adapted and are designed for the maximum exhaust inlet operating temperature of 1020°C (1868°F).

The diverter valves are now integrated in the charge air line and have a hose connection to the turbocharger compressor inlet side (See the graphic on the next page).

Catalytic converters and oxygen sensors are the same as in the N63 with the cable routing of the oxygen sensors adapted accordingly to the new engine.

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COLD END EXHAUST SYSTEM REFERENCE CHART

Exhaust Components After Catalytic Converter "Cold End"

The exhaust system downstream of the catalytic converter in the E7x M is based on the exhaust system of the E71 xDrive 50i and adapted to the requirements of the S63 engine.

Particular attention was paid to ensuring optimum pipe layout routing using the largest possible pipe diameter.

The four M tail pipes with chrome tips round off the dynamic and sporty appearance of the vehicles.

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E70/E71 M COOLING SYSTEMS REFERENCE CHART

Intake Silencer (AGD)

To enhance air flow to the engine while taking pedestrian protection into consideration, the intake silencer has been redesigned and fixed to the body directly in front of the engine (on N63 its fixed to the engine). Two activated carbon filters prevent pollutants (that could stem from the engine) from entering the intake system when the engine is not in operation, complying with corresponding emission requirements.

US models use an intake silencer with an integrated snow valve and additional activated carbon filter mesh.

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Snow Valve

The snow valve is a filter bypass valve that is opened by engine vacuum. It allows continued engine operation (at greatly reduced power output) if necessary, should the air cleaner be iced up or closed off with packed snow in extreme wheather conditions.

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Vacuum Supply

The vacuum pump has been adopted from the N63. The two plastic vacuum accumulators each with a volume of 0.3 l are new and are located under the engine cover (N63 uses one accumulator designed as a metal cylinder under the turbochargers).

Cooling Systems

As in the series production X6 (xDrive50i) the X5/X6 M have two cooling systems, the main engine cooling system and a low temperature cooling system dedicated to intake charge air cooling (turbo intercooling). The following components have been adopted from the N63 and are common with series production E71 vehicles

1. The low temperature system heat exchanger for the intercoolers
2. Air conditioning condenser
3. Power steering oil cooler
4. The standalone auxiliary radiator

The expansion tank for the main engine cooling system was taken from the E70.

New and Adapted Cooling Components

The main coolant radiator takes up the same package space as in the E71 but has a winglet tubing design, for increased surface area. It no longer contains the integrated low temperature area for the transmission oil-to-coolant heat exchanger.

The engine oil cooler has been adapted to the higher engine output by increasing the core depth from 30 mm to 45 mm.

The charge air (low temperature) cooling system has an additional intercooler heat exchanger installed in series, a second auxiliary water pump and a new expansion tank. The length of the engine intercoolers (LLK) has been increased from 130 mm to 160 mm. The measuring range of the boost pressure sensors at the intercooler outlet has also increased to 4 bar.

The transmission oil heat exchanger has been adapted to the higher engine output by increasing the number of plates from 23 to 31.

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GEAR RATIO REFERENCE CHART

Cooling Module Components

The components highlighted in "blue" (*) below are new or have been newly designed to meet the specific requirements of the M powertrain. The components highlighted in "red" are carried over from the series production E71 xDrive50i model.

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Transmission

With the M Sport automatic transmission 6HP26S the customer is able to enjoy spontaneous gearshifts and a more stable control of the torque converter lock-up clutch.

To effectively absorb rotational irregularities in the drive train and achieve the best possible reduction of the slip at the converter lock-up clutch, a double-damper torque converter is installed. A single-damper torque converter design is used in the 6HP26TU of the E71 xDrive50i.

The spring characteristics in the double-damper converter are especially designed for the increased power and torque of the S63 engine. The 6HP26S internal components have also been adapted to the maximum engine speed of 6800 rpm.

The plastic transmission oil pan has been replaced with an aluminum version. The air flow to the transmission has been enhanced and the opening point of the transmission oil thermostat has been lowered.

The gear ratio is identical to that of the series production 6HP26TU transmission.

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DYNAMIC DRIVING PROGRAM REFERENCE CHART

M Gear Selector Lever (MGWS)

The functional design of the M gear selector lever is similar to the series production E7x. A new feature of the design is the integrated M logo in the gear indicator of the M gear selector lever.

The button for the electronic damper control (standard equipment feature) is positioned on the base of the gear selector lever.

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Transmission Control

The electronic transmission control unit (EGS) for the 6HP26S, is integrated into the transmission case as on the series production model.

The transmission control software is adapted to M specific requirements.

The transmission now features even shorter shift times in manual mode, ensured by a new type of torque reduction system involving cylinder cutout. This feature along with the short axle transmission ratio emphasize the sporty characteristics of the vehicle.

A special M shifting program ensures quick and precise gear changes and enhances throttle response throughout the three driving modes.

Shift times and accelerator pedal characteristics can be adapted to the driver's preference and driving situation

BRAKE SYSTEM REFERENCE CHART

Note. The weight of the transmission has increased slightly as the result of the converter technology used.

Launch Control

Launch control ensures optimum vehicle acceleration when starting on a road surface with sufficient grip.

Activation is not possible if one of the preconditioning requirements is not met and if the transmission oil temperature is too high.

The alternator power output is reduced to zero when launch control is activated, in order to further optimize power. However the A/C compressor remains active to address possible window fogging.

Note. For further information regarding E70/E71M Launch Control refer to the vehicle Owner's Manual.

Transfer Case and Final Drive

The xDrive transfer case and input/output shaft have been adopted from the series production models. The rigidity of the rubber mounts in the transmission mounting has been adapted to the application.