Via a button on the right clip-on, the rider can choose between Rain, Sport, and Race modes. Clipping the S 1000 RR's wings to "only" 150 horsepower, Rain mode offers an "extra soft and smooth" throttle response to maintain traction off the corner, with the DTC cutting in early in order to avoid any wheelspin whatsoever. Sport mode provides full engine output at a claimed 193 horsepower at the crankshaft, but with a more spontaneous and direct throttle response, with the DTC waiting until much later before intruding on the proceedings. Race mode was "developed specifically for racing the S 1000 RR on racetracks using street-legal supersports tires...with even more direct and significantly more dynamic [throttle] response at all speeds" according to BMW, and again here the DTC stays out of the picture even later than the Sport mode in order to exploit the increased traction available. Not only are these different maps accessible via the bar-mounted button, but they can also be switched on the fly (although it requires that the throttle be completely shut and the clutch pulled in).
The S 1000 RR's cockpit is...
The S 1000 RR's cockpit is clean and purposeful, with a dual LCD panel display offering a wealth of information without being too cluttered. Programmable shift light is large and positioned in the right area.
The extruded aluminum swingarm...
The extruded aluminum swingarm sports a banana-style curvature on the pipe side to make room for the stainless steel under-engine exhaust with short-tip muffler. Note the thin spokes of the cast aluminum wheel, as well as the wide range of axle adjustment in the swingarm carrier.
Radial-mount/four-piston Brembo...
Radial-mount/four-piston Brembo calipers grip 320mm discs that are mounted directly to the front wheel hub, eliminating the need for disc carriers. Optional Race ABS disc rings are visible in this photo; inverted cartridge fork sports 46mm tubes for better stability under braking.
The bottom end of the engine sports the now-ubiquitous stacked gearshaft arrangement to make the overall assembly more compact front-to-rear, with a ramp-type slipper clutch helping to reduce back-torque wheel hop. Nikasil-lined cylinders have been cast into the upper case half for strength, and the gear engagement dogs have been undercut to ensure positive shifts.
A large centrally-located...
A large centrally-located ram-air intake ensures maximum airbox pressure at speed. Note the three cutaway holes on the outer portion of the windscreen; these allow pressure equalization behind the windscreen at speed and reduce buffeting.
Inhalation is through a ram-air system being fed directly through the steering head from the center point of the fairing nose, with the 7.9-liter airbox featuring the BMS-KP ride-by-wire EFI system utilizing 48mm throttle bodies with single throttle plates and dual injectors per cylinder. As with the Yamaha R1/R6 and other newer sportbikes, the intake trumpets are length-variable in two stages according to rpm to help with intake pulses for better low and top-end power. In order to ensure maximum pressure at speed to the intakes, the air filter is positioned vertically instead of horizontally (laying flat) in the airbox to avoid excessively diverting the direction of airflow. The system also has a cylinder-specific anti-knock control that can adjust ignition and fuel requirements according to the octane rating of the fuel, with two O2 sensors ensuring optimum low-rpm fueling requirements.
The BMW's under-engine exhaust...
The BMW's under-engine exhaust utilizes three internal chambers to reduce noise, along with an exhaust butterfly valve to regulate back pressure and allow a short exit muffler unit out the right side.
The stainless 4-into-2-into-1 exhaust utilizes the increasingly popular under-engine chamber/pre-silencer to centralize mass, with three internal compartments to help reduce excess noise and emissions before exiting the short exit muffler. To assist cylinder scavenging, the primary header system features balance connector pipes with two internal butterfly valves controlled by the ECU that help "tune" the exhaust to a particular rpm/throttle setting for maximum power.
These cutaway CAD illustrations...
These cutaway CAD illustrations show how the adjustable intake trumpets are moved into two positions by an ECU-controlled motor according to rpm. Note that the paper air filter is set up vertically instead of laying flat like most airbox installations; BMW feels that forcing the airflow to change directions is detrimental to airbox pressure and power production. Air enters straight through the hollow steering head.
Borrowing some of its Formula...
Borrowing some of its Formula One engine technology, BMW engineers positioned the intake cam follower pivot on the front side of the intake cam, thus enabling a straighter intake port path for improved flow. Because the followers are not directly attached to the valve springs, reciprocating weight is reduced, allowing higher rpm without valve float.
The S 1000 RR's exhaust system...
The S 1000 RR's exhaust system utilizes two equalizer tubes connecting cylinders 1 and 4, plus 2 and 3. An ECU-controlled butterfly valve in each equalizer tube regulates exhaust pulsations to promote exhaust scavenging and improve power.
Rain, Sport, Race & Slick
Like many of today's sportbikes, the BMW offers a choice of different engine maps-but the S 1000 RR offers a bit more than the usual three modes. In addition to the different engine maps, changing modes can also select differing levels of the optional Race ABS and DTC (Dynamic Traction Control). Unlike the previous ASC (Automatic Stability Control) traction control system that had only one setting, the DTC changes its settings by determining the actual lean angle of the bike using various sensors.