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출처: 대전 BMW Stormbringer 원문보기 글쓴이: 길주영
A centrally located ram-air duct provides pressurized cold air through the steering head into the airbox. |
A stainless steel four-into-two-into-one exhaust system keeps its weight low and centralized. Three exhaust valves enhance its power production and sound. |
As we were learning a new bike and a new track, we were advised to begin with the ECU set to the Rain mode. This smooths throttle response and limits engine output to a maximum of 150 horsepower. And with the DTC/ABS option, it also restricts throttle application at lean angles greater than 38 degrees; making it ideal when riding on low-adhesion surfaces.
However, on a dry and grippy racetrack like Portimao, the system proved way too intrusive. Especially off-putting was the ghost in the machine that prevented application of throttle when at a corner's apex while the bank-angle sensor was beyond the 38-degree threshold. Then, once at 37 or fewer degrees, power comes on suddenly and gives the pilot the feeling that he's not fully in control.
Still, there was much to appreciate from this restricted first session. BMW's RR feels as nimble as a Honda CBR1000RR, the most agile of existing literbikes, and it continues steering well even while trail-braking. It feels lighter than its fully fueled 450-pound weight would indicate. Ergonomics feel racy but not brutal, with pegs set back quite far.
Although the engine is detuned in Rain mode, there is still plenty of power on tap. BMW's RR has the largest bore (and, correspondingly, shortest stroke) of its competition, and this usually hinders low-end and midrange power. BMW fills in those low-rev holes with technologies that alter the flow of air in and out of the engine.
On the intake side are variable-length throttle trumpets, using a longer, torque-enhancing configuration at lower revs before splitting apart to reveal a short intake runner for maximum power at high rpm. Spent gasses are at the mercy of three exhaust valves. A butterfly valve bridges the header tubes of cylinders 1 and 4, and a second butterfly joins cylinders 2 and 3. A third exhaust valve located ahead of the tailpipe is described by BMW as an “acoustic flap,” which is in place only to limit sound emissions at lower revs.
Session Two – Sport Mode
It only took a few corners to realize the Sport setting is much preferable in dry, high-traction settings than the Rain mode. Throttle response is still smooth and the bank-angle sensor is still in play, but in Sport mode it only limits throttle openings at lean angles beyond 45 degrees. Within these parameters, a rider is still able to cut fairly quick laps
Without the Rain setting's restriction of power output, the S1000RR is able to unleash its full 193 claimed crankshaft horsepower, although throttle application is more progressive than the Race or Slick settings. Full-throttle acceleration is something near ferocious, and I'd estimate a rear-wheel horsepower number near 170, which would make the S1000RR the most powerful literbike available.
The S1000RR is remarkably easy to hustle around a racetrack, with or without its many electronic rider aids. |
The S1000RR proves BMW knows how to build a high-performance engine. It likely has about 170 horses at the rear wheel, which is more than any of its competitors. |
In its spec chart, BMW states the S1000's maximum speed is “over 200 kph,” which is a bit of a joke because the uber-sport Beemer was carrying its front wheel up the front straight beyond 240 kph – that's 150 mph to us Ah-mer-cans. Peak torque of a brawny 82.6 ft-lbs arrives at 9750 rpm, while 193 ponies are bolting the corral at 13,000 rpm, 1200 revs short of its lofty rev limit.
A limitation of Sport and Rain modes is a form of wheelie control based on wheel-speed sensor data. If acceleration forces the front tire off the ground, it soon will be spinning slower than the rear. The ECU perceives this data as a loss of traction, and the DTC cuts power and therefore brings the front wheel back in contact with the tarmac, sometimes ungracefully.
With the most powerful engine in its class, this is a pose the S1000RR frequently makes. |
In the lower gears where acceleration is strongest, a rider can be presented with a wheelie followed by a fairly aggressive intervention of power, then, once wheel speeds are equalized, full power resumes that can again initiate another wheelie and another power interruption. Disabling the DTC prevents such histrionics.
Another rider aid, this one based on the Race ABS, is present in Rain and Sport modes. If the ABS senses the rear wheel is lifting off the ground during hard braking, it will subtly release a bit of front brake pressure to bring down the rear end, an operation that is transparent to the rider. .
Session Three – Race Mode
The unfastening of three bolts quickly removes the license-plate mount, fender and rear turnsignals. |
Stefan Zeit, Project Manager for the S1000RR, says Race mode is best for 90% of trackday riders. It offers more aggressive throttle inputs, nearly the one-to-one ratio of Slick mode. A rider is aware of the higher state of tuning by throttle response that is occasionally but not always slightly abrupt upon reapplication.
The DTC in Race mode allows 48 degrees of lean before affecting throttle application, and that's a fairly deep angle of dangle for most riders. Even with excellent grip from the standard-equipment Metzeler Racetech K3s, the DTC is reassuring and really aids confidence on corner exits. This higher-performance mode also enables bigger wheelies before power is reduced.
The parameters of the Race ABS is also geared toward faster riders in the Race mode, so the rear-wheel lift-off detection is disabled. I'm happy to report the S1000RR has very little of the oft-maligned pulsing feel of some anti-lock systems. Only a few times while bleeding off 170 mph into Turn 1 did I feel any mediation of the ABS. Kudos to BMW for building such a clever system that adds only 5.3 pounds to the bike. The performance anti-lock system on Honda's CBRs add 22 pounds of ballast to its RRs.
The S1000RR at Portimao – two of Duke's new favorite things. |
Speaking of rider aids, it was a pleasure to be turning laps with the help of BMW's Gearshift Assistant. The quickshifter simplifies upshifts by briefly cutting the ignition to enable grabbing the next gear without using the clutch or letting off the gas – seamless acceleration is available by simply kicking the foot lever. It makes a squeaky-squooshy sound faintly akin to a turbo's wastegate letting off excess boost
Session Four – Slick Mode
You gotta be serious if you want to get into Slick mode – you can't even access it unless it is enabled by an optional accessory to plug into an underseat port. The “Slick” part refers to racing tires, not traction.
Slick mode allows 53 degrees of lean angle before throttle application intervention, and you've got to be a moderately heroic rider to be demanding more power while leaned over at, say, 55 degrees. If you are that person – perhaps factory BMW rider Troy Corser – you're free to disable the DTC with a long push of a single button.
Lean angle is plentiful. |
The new Beemer's ergonomics are compact but not overly cramped. |
Slick mode also allows access to wheelies without disabling the DTC, but there are still a couple of electronic nannies in place to keep a rider safe. Mono-wheeling remains verboten if the bike is at a lean angle greater than 23 degrees, and the duration of a wheelie is limited to five seconds of fun before the electronic cops are called in to spoil the party. If wheelies are a prerequisite in your hooligan world, simply turning off the DTC will enable your Jason Britton imitations.
One other noteworthy trait of Slick mode is that the rear brake loses its anti-lock control so your inner Ben Bostrom can pull hackers on corner entries. Truth be told, I barely remember even using the rear brake. The Brembo radial-mount front calipers and 320mm floating front rotors are deliciously powerful, exhibiting exemplary feel through steel-braided lines without a harsh initial bite.
I spent the rest of my day in Slick mode, as it was the closest comparison to the literbike rivals without disabling the traction control entirely. Positive impressions were plentiful.
First off, I was amazed at the grip and durability of the Racetech K3s. Good front-end feel and feedback through the beefy 46mm inverted fork inspired confidence, and the S1000 needed to be ridden quite aggressively before I could get the footpeg feelers to skim the pavement. Corner entries are aided by a back-torque-limiting (slipper) clutch that performed well.
Not a lot of time has passed since the recent construction of the Portimao circuit, so there weren't many bumps on which to test the S1000's fully adjustable suspension. As set up, it performed perfectly, and we award BMW kudos for giving each compression and rebound damping adjuster clearly labeled numbers from 1 to 10 to simplify keeping track of your settings. Front and rear ride heights are also adjustable.
Multiple trips to the S1000's redline gave plenty of opportunities to sample the characteristics of BMW Motorrad's highest specific-output engine ever, and I was surprised the non-counterbalanced engine didn't give off objectionable vibration at any speed. Christian Landerl, Executive VP Development and Model Lines, BMW Motorrad, told us it was because of the engine's lightweight components and the particular frame design.
Although it's BMW's first foray into the liter-sized sportbike market, the S1000RR is already a well-honed package. |
Landerl, who began work on this project nearly five years ago, pointed out the Formula 1-influenced valvetrain that uses finger followers made of forged steel and treated with DLC to toggle the four titanium valves per cylinder – many engines with Ti poppets use steel valves on the exhaust side. Landerl claims the S1000's design allows valve actuation components to be 30% lighter than a conventional shim-under-bucket design, key to the high 14,200-rpm redline. Landerl says it could safely rev to 15K. As it is, the S1000 has fairly lengthy 12,500-mile valve adjustment intervals.
[출처] S1000rr ECU 주행모드 (BMW Sports Riders club) |작성자 고산