2007 BMW Sauber F1.07
BMW Sauber F1.07 – a cast of experts - Time was of the essence in the development of the F1.06, the first car developed by the BMW Sauber F1 Team. Indeed, BMW only took the decision to purchase a majority stake in the Sauber team in June 2005. The components already in the midst of a lengthy development period (the chassis, engine and transmission) were moulded into an overall package – and with notable success, as the results over the course of the season just gone can testify. However, the shortage of time available meant that compromise was unavoidable in certain areas.
The BMW Sauber F1.07 started out from a very different basis. Work on the concept began in April 2006 and took shape as part of a close cooperation between the chassis experts in Hinwil and their colleagues in Munich responsible for the powertrain, i.e. the engine and transmission, and the electronics.
Priorities were set out from day one and all the aspects of the project brought together to create a harmonious overall package. “We have channelled our experience with the F1.06 into the new car, but at the same time focused on the new challenges presented by the 2007 regulations”, explained Willy Rampf, Technical Director of the BMW Sauber F1 Team. To this end, the most significant change is the switch to a single tyre supplier in Bridgestone. In accordance with the stipulations of the FIA, the Japanese company has produced tyres which offer less grip as a means of lowering cornering speeds.
“It’s clear that the cars are going to slide around more. It was therefore important for us to build a car that is easy to drive and that our drivers can trust sufficiently to go on the attack”, added Rampf, giving an insight into the team’s development strategy. “We should also expect the cars to run with rather greater downforce as a rule, in order to make up for the loss of grip.”
The nose has it
Aerodynamics has been a key area in Formula One for a long time now, but the advent of the single tyre supplier format in 2007 will raise its importance even further. “If you look at all the components which affect the performance of a Formula One car, aerodynamics represent – by a distance – the single most important factor”, emphasises Rampf. All of which explains why the BMW Sauber F1 Team top brass gave the expansion of the aerodynamics department top priority. The team’s use of the wind tunnel in Hinwil was gradually increased, with a move initially from one to two shifts, and from there to a round-the-clock three-shift system in late October 2006. This has given the team parity in this area with its rivals – who have long had comparable systems in place – and fulfilled a central requirement in achieving its ambitious aims.
As always, the key is to enhance aerodynamic efficiency. However, almost as important this year is the need to develop a package that functions as well as possible through corners. Here, the front wing has an influential role to play, largely dictating the flow of air around the front tyres. It has been completely newly developed and forms a harmonious unit with the likewise totally new nose section, which is shorter and sits higher than its predecessor. This results in a reduction in its weight, but also places extra demands on the engineers when it comes to passing the FIA crash tests. The most important aspect of this development, though, is that the wing channels a large amount of air under the car, allowing the underbody and diffusor to work to their full potential.
New cooling concept
The cooling intakes are somewhat larger than those on the 2006 car and represent part of a new cooling concept which is more effectively integrated into the overall package and designed to ensure greater air throughput. The air is diverted upwards to maximum effect, improving aerodynamic efficiency compared to last year’s car, especially in high outside air temperatures. As Rampf explains: “We took a lot of time in the conceptual phase to find the best possible solution in this area. This is an important point, as the air temperature at the first races of the season, in particular, are traditionally very high. The cooling concept of the F1.07 promises to deliver impressive efficiency in all conditions.”
The designers built of the knowledge gained with the F1.06 in the development of the rear, giving the tail an even slimmer and lower profile in order to further optimise the air flow around the rear wing. The basis for these modifications is provided by the compact quick shift gearbox and cleverly positioned hydraulic elements. Also integrated into the design are the exhaust pipes, whose form was defined to maximise performance and fit harmoniously into the overall package. The section underneath the rear wing is a totally new development.
More stringent regulations governing rear-end collisions have meant that the rear crash element is now more voluminous overall and also has a modified form. The lower positioning of this element has required a totally revised design for the centre section of the diffusor. The engineers were also instructed to reduce the car’s weight, while maintaining its rigidity. The affects the monocoque, which is made up of up to 60 layers of carbon fibre in places, as well as individual components. “It’s always good if you can use a lot of ballast, but in the situation we have now it’s particularly important, as it ensures outstanding flexibility in terms of weight distribution. And that plays a critical role in the optimum use of tyre potential”, explains Rampf.
New suspension elements
The construction of the suspension elements is totally new and, at the front axle, dictated primarily by aerodynamics. The raised nose section mean that the wishbones slant downwards at a striking angle. The kinematics have been modified in response to the introduction of the standard Bridgestone tyres. “We were also very keen to give the steering a high level of feedback”, says Rampf. “This area has gained even further in importance as a result of the cars’ reduced grip levels. The harder tyres will, by definition, cause the cars to slide around more, which means the drivers will have to do a lot more correcting as a result. And that makes good steering feedback indispensable.” The rear axle was also modified to further improve traction.
Comfort and Formula One make uneasy bedfellows. And yet, one of the focal points in the development of the F1.07 was an increase in comfort. This is expressed specifically in the seating position of the drivers, especially that of Robert Kubica. The Pole’s 184-cm frame was a far from comfortable fit in the 2006 car, whose cockpit area was particularly tight. As Rampf points out: “We only have restricted room for manoeuvre in this area, but we’ve done what we can to give Robert a pleasant seating position in the new car.” There has also been progress in the area of electronics, which combine the workings of the chassis and powertrain in the interests of integration.
The electronics for the chassis, engine and transmission have now been brought together into a single control unit, whose space-saving design allows it to be accommodated in the cockpit without taking up too much room. “We created a solid basis for this year’s car in our first season on the grid. The cooperation between the team members in Munich and Hinwil is now working well, and the additional resources give us extra potential. Our aim is now to further reduce the gap between ourselves and the top teams”, said Rampf, looking forward optimistically to the new season.
BMW Sauber F1.07 – technical data
Chassis: carbon-fibre monocoque Suspension: upper and lower wishbones (front and rear), inboard springs and dampers, actuated by pushrods (Sachs Race Engineering) Brakes: six-piston callipers (Brembo), carbon pads and discs (Brembo, Carbone Industrie) Transmission: 7-speed quick shift gearbox, longitudinally mounted, carbon-fibre clutch (AP) Chassis electronics: BMW Steering wheel: BMW Sauber F1 Team Tyres: Bridgestone Potenza Wheels: OZ Dimensions: length 4,580 mm width 1,800 mm height 1,000 mm track width, front 1,470 mm track width, rear 1,410 mm wheelbase 3,110 mm Weight: 605 kg (incl. driver, ready to drive, tank empty).
Engine. V8 reloaded
Following the fundamental conceptual shift from V10 to V8 engines ahead of the 2006 season, the focus is now on the development of clever details for the Formula One powerplants of the future. In 2006 the decision was taken to freeze large areas of engine development until after the 2010 season. The homologation of the 2.4-litre V8 units requires technical monitoring and has been conducted in several stages.
The Formula One teams’ engines started to appear at the FIA office in Chessington, England towards the end of the 2006 season. All the manufacturers were required to submit an engine which had come through two GP weekends. To be on the safe side, BMW decided to put aside the first P86 engine as early as Monza, with further development work continuing apace at the same time. Having met its obligations, the team had earned itself extra room for manoeuvre when it came to making improvements. The engines in Nick Heidfeld and Robert Kubica’s cars completed the final races of the season in Japan and Brazil without a problem, and Kubica’s unit was handed over to the FIA.
The deadline for engines was 22nd October, but that didn’t mean the engineers could go into hibernation for the winter. The teams were able to submit a list to the FIA – by 15th December 2006 at the latest – containing modifications to the engine (except the pre-specified core) which they were intending to carry out by 1st March 2007 in order to adapt it to the rev limit of 19,000 rpm. In simple terms, while the block and crankshaft had to remain untouched, further tweaks were allowed to the cylinder head and peripheral components. Additional enhancements were permitted to details of the intake and exhaust piping, lubricant and fuel supply, pistons, valves and mounts. Alterations required to install the engines in the new cars were also given the green light. A new central control unit for the engine, transmission and chassis replaces the previous engine electronics. The new development has been christened RCC, standing for Race Car Controller. The designation of the BMW power unit reflects the fact that the engine concept must remain unchanged: it will be known as the BMW P86/7, rather than the P87.
Fixed parameters for all
The introduction of the V8 engines in time for the 2006 season was underpinned by a series of central parameters governing their construction. Displacement of 2,400 cc and a bank angle of 90 degrees were stipulated for the V8 engines. The powerplants had to tip the scales at no less than 95 kilo¬grams. This included the intake system up to and including the air filter, fuel rail and injectors, ignition coils, sensors and wiring, alternator, coolant pumps and oil pumps. It did not include liquids, exhaust manifolds, heat protection shields, oil tanks, accumulators, heat exchangers and the hydraulic pump. The new regulations stipulate that the engine’s centre of gravity must be at least 165 millimetres above the lower edge of the oil sump. The longitudinal and lateral position of the V8’s centre of gravity has to be in the geometric centre of the engine (+/– 50 millimetres).
The cylinder bore is limited to a maximum 98 millimetres. The gap between the cylinders is also set out in the rulebook – at 106.5 millimetres (+/– 0.2 mm). The central axis of the crankshaft must not lie any less than 58 millimetres above the reference plane. Variable intake systems designed to optimise torque have also been banned since 2006. The power supply to the engine electrics and electronics is limited to a maximum 17 volts and the fuel pump has to be mechanically operated. Only an actuator may be used to activate the throttle valve system. With the exception of the electric auxiliary pumps in the petrol tank, all subcomponents must now be driven mechanically and directly via the engine. In addition, a long list of exotic materials have been excluded and the team limits itself to working with the conventional titanium and aluminium alloys stipulated in the regulations. Another restriction which will come into force for 2007 and the following years is a cap placed on engine speed at 19,000 rpm.
V8 development from November 2004 to February 2007
Development work on the BMW V8 engine began in late November 2004. The champagne was flowing at BMW’s Formula One engine factory at Anton-Ditt-Bogen in Munich in May 2005 after the first-specification V8 successfully completed its opening examination on the test rig. An updated specification made its track debut in Jerez on 13th July 2005. A further developed version was then introduced in time for winter testing, which began in Barcelona on 28th November 2005. The next stage of development was ready for the first rollout of the new car on 17th January 2006, and this was followed by another update for the first race of the season and a series of new specifications as the year went on. The later versions were developed with one eye on the homologation process to come. As Theissen explains: “A Formula One engine is never the finished article. It’s like a painting that may already look finished to the onlooker but which the artist, knowing precisely where he can improve his work, will still touch up here and there. A single stroke of the brush can change the whole effect. Far from reducing development work to a standstill, the increased number of regulations has merely shifted the emphasis. It’s important that Formula One remains at the cutting edge of technology, and that’s what it will do.” Power for longer.
The mileage a Formula One engine is required to cover has changed dramatically in the recent past. 2002 was the last season where a new engine could be fitted ahead of every race. Back then, qualifying saw the use of highly tuned engines which the teams would never have dared risk over a full race distance. In 2003 the rules changed to force the teams to use the same engine for qualifying and the race itself, and that was followed by the introduction of the whole-weekend stipulation in 2004, doubling the mileage the engine had to cover. Since 2005 the engines – then still 3-litre V10 units – have had to hold it together for two full GP weekends. An unwanted side effect of this rule saw the GP drivers preserving their engines during Friday practice and staying in the garage as much as possible.
In order to offer the fans more in the way of action, the Friday sessions have now been granted exemption from the engine regulations for the 2007 season. This will encourage the drivers to spend more time out on the track during what are now two 90-minute sessions. Only from Saturday will the teams be obliged to fit the engines in their cars which must then last two GPs – under the watchful eye of the FIA. Longer at full throttle. The lower output of the V8 compared to the V10 engines means the cars spend longer under full throttle. BMW’s figures show that the average proportion of the race spent at full throttle in 2005 was 56.67 percent, with that figure rising to 63.53 percent in 2006.
Practice behind closed doors
Before a new specification reaches race readiness, it has to successfully complete an extended session on the dynamic test rigs. BMW first introduced the new-generation testing facilities, which stretch out over several floors and fill entire halls, in autumn 2005. The exacting challenge for the powerplant remains unchanged: 1,500 kilometres on a pre-programmed circuit profile based on Monza. No other GP venue can match the full-throttle percentage of the Italian track. Engines earmarked for transportation to the race venue complete a rather more gentle functioning check on the test rigs. This is followed by quality checks, with the oil undergoing spectrometer analysis to identify any metallic residue. Then it’s time for action on the track.
One section of the new testing facility at Anton-Ditt-Bogen is used by the transmission development and testing department now based in Munich. A Formula One race transmission needs to display maximum rigidity, yet at the same time be lightweight, have a low centre of gravity, be compact and boast extremely short shift times. The BMW Sauber F1.07 is fitted with a 7-speed gearbox. The main and auxiliary drive shafts are arranged longitudinally to the direction of travel.
The driver can shift up a gear without breaking off tractive power to the rear axle. In a conventional Formula One transmission, engaging the clutch results in the flow of tractive power being interrupted for approximately 50 milliseconds during the shift process. In other words, during this time the car is deprived of propulsion and just rolls – in particular at high speeds against high wind resistance. In practical terms, the car is braked by around 1g during this suspension of tractive power. In a road car, this would come across as powerful braking.
This interruption of tractive power every time the driver shifts up a gear – which he will do some 2,000 times over the race distance of the Monaco Grand Prix – adds up to a significant loss of time or a deficit of several hundred metres by the end of the race. The new quick shift gearbox (QSG) fitted in the BMW Sauber F1.07, however, totally eliminates this break in tractive power. The ingenious interplay of electronic and mechanical components is the key. Both the development and production of the QSG takes place in Munich.
The transmission’s extremely durable toothed gears – partly manufactured at BMW’s Dingolfing plant – are made of high-strength steel, while the transmission housing consists of cast titanium. Converting torque and engine revs is just one of the transmission’s jobs. It also has to pass on the forces generated in the suspension to the chassis via the engine. Made for the track, benefits for the road. One of the aims stated by BMW for its return to GP racing in 2000 was the creation of synergies between F1 and series production. The development of the Formula One powertrain and electronics has been integrated with impressive effectiveness at the Munich plant. The BMW Research and Innovation Centre (FIZ), a type of automotive think tank, plays a key role in this process.
The F1 factory was built less than a kilometre away from the centre and the two facilities are interconnected. “The FIZ represents the future of BMW, with elite engineers working in state-of-the-art research and development facilities”, says Theissen. “The FIZ is given vast resources, from which we benefit directly. At the same time, due to the extreme technical challenges and pace of development demanded by grand prix racing, the company’s involvement in F1 represents a unique proving ground for our engineers.” BMW has made the vision of a seamless process chain a reality, following the development from concept to construction, casting, component production, assembly and testing all the way to race action on the track – and all under its own roof.
Transportation of parts – and the quality problems this can cause – is no longer an issue, and the expertise acquired remains within the company, where it benefits the development of production cars.
Casting technology for Formula One and series production
The casting quality of the engine block, cylinder head and gearbox plays a crucial role in determining their performance and durability. Advanced casting techniques, coupled with high-precision process management, enable lightweight components with impressive rigidity. To ensure that production models benefit from these developments, BMW has its own foundry in Landshut. In 2001, this was joined by a dedicated F1 casting facility.
The two departments are jointly managed and that ensures a constant exchange of information and expertise. The same sand-casting procedure as is used for the production of the Formula One V8 engine is also applied to oil sumps for the M models, the intake manifold for the eight-cylinder diesel engine and prototypes for future generations of engines. Virtually at the same time as the F1 foundry went on stream, an F1 parts manufacturing facility based on the same template joined the series production facility.
This is where the team make components such as the camshafts and crankshafts for the F1 engine. Electronics for race day and every day. With the backing of the electronics experts at the FIZ, BMW also had the confidence to develop its own F1 engine management system for its GP comeback. Turning to established motor sport specialists might have been the easier option, but such a move would have done little to augment the knowledge base in Munich. Engineers normally devoted to developing the electronics for the M models also created the engine management system for the F1 engines.
The expertise they gained in the process filters back into series production. Top-of-the-range BMW cars, such as the 7 Series and M models, have long featured two types of microprocessor which BMW has used and tested in Formula One. Added to which, data storage technology which had first proved itself in F1 was used to hone internet access and the navigation system for the BMW 7 Series. F1 technology is also used in monitoring systems for a variety of vehicle functions – another area which is gaining in importance in road car development.
Early warning systems and automated electronic intervention technology can play an important role in enhancing safety and guarding against damage in production cars as well as racing machines. The demands on the engine management system of a high-revving Formula One engine, which also has to run smoothly at low engine speeds, are immense.
The ignition timing and fuel supply have to be perfectly coordinated millisecond by millisecond in order to achieve optimum efficiency – maximum output combined with low fuel consumption. Optimising fuel economy can enable both better lap times and greater flexibility in race strategy.
One of the electronics and transmission innovations from Formula One to have proved its mettle in the BMW M3, M5 and M6 is the “Sequential M Gearbox – SMG with DRIVELOGIC”. The SMG drive concept delivers F1 transmission technology for everyday use. The driver changes gear electrically via paddles behind the steering wheel. As in Formula One, an electrohydraulic system replaces the mechanical clutch and shift process, and SMG users can similarly keep their foot on the accelerator while changing gear.
Material research for the future. Despite the introduction of even more stringent regulations into GP racing, the materials used in today’s F1 cars still have to be “as lightweight as possible and as durable as necessary”.
The materials research section at the FIZ provides crucial input for the development of BMW’s F1 engines and transmissions, with aviation and aerospace technology frequently serving as a basis. Some highly promising developments, which as yet remain too expensive for use in production models, have already found their way into BMW’s F1 project.
This opportunity to introduce fresh technological blood helps the engineers to continue developing innovations for series production Rapid prototyping – models in double-quick time. From the new idea and the conception phase to the construction process, production of the necessary tools, manufacture of new parts and testing, new components are expensive and time-consuming to make. In Formula One, moving forward and addressing problems demands fast reaction times, while the number of design modifications made during a single season has been as high as for the entire BMW range of series-produced engines.
The team is therefore constantly on the lookout for ways of shortening its processes. Here the BMW Formula One engineers can turn to the Rapid Prototyping/Tooling Technology department of the FIZ. Once the necessary parts have been designed – using a CAD system – computer-controlled machines use laser beams or three-dimensional pressure technology to create scale models made out of resin, plastic powder, acrylic, wax or metal. That enables installation and interactions to be simulated without delay, allowing any necessary modifications to be carried out before the final manufacturing process gets underway.
BMW P86/7 – technical data.
Type: normally aspirated V8 Bank angle: 90 degrees Displacement: 2,400 cc Valves: four per cylinder Valve train: pneumatic Engine block: aluminium Cylinder head: aluminium Crankshaft: steel Oil system: dry sump lubrication Engine management: BMW Spark plugs: NGK Pistons: aluminium Connecting rods: titanium Dimensions: length: 518 mm width: 555 mm height: 595 mm (overall) Weight: 95 kg