2007 Bahrain GP Technical Review

With the Bahrain race coming just a week after the Malaysian race, there has been no time to test or develop new parts. Thus the similarity in the two circuits proved useful to the teams, with both tracks being fast with high ambient temperatures. As there were almost no developments to speak of at Sakhir, this is a good point to consider how the teams are faring and to look into detail on some of the cars.

The Circuit

Although similar to Sepang, the Sakhir circuit has its own demands on the cars. As a modern wide track, the featureless circuit is made up largely of the three straights linked by slow corners. Due to the simplicity of the layout the car is either accelerating to maximum speed or braking, in fact two thirds of the track is on open throttle. Aiding the teams' reliability was the scheduled replacement of most the engines, which had run the two previous races.

This fast/slow nature is without any long challenging corners, yet the track's grippy bumpless surface places a heavy toll on brakes and tyres. Much like the Malaysian race, most of the teams arrived in Bahrain having tested here already. This allowed the teams to evaluate the tyres, set up and cooling for the race. For the old Michelin runners the extra tyre knowledge helped reduce the gap to the existing Bridgestone teams, as they had no data for this track.

However with the Sakhir circuit being based in the desert and used infrequently, the surface changes during the weekend as the track rubbers-in and the wind blows dust onto the track. Exacerbated by these changes, tyres are prone to degrading and excessive wear. In the race many cars suffered understeer and others overly worn rears.

The set up conundrum for the teams was the downforce needed to protect the tyres while maintain speed on the straights. Moreover the penalty for heavy fuel was particularly bad; many teams opted for long middle stints and this either wrecked their overloaded rear tyres or stymied their pace.

In the course of the race all teams opted for the white-lined 'soft' tyre as the primary choice, only changing to the hard tyre for the last stint. In the practice sessions the softer tyre was the clear choice, unlike the more marginal difference in Sepang. Liuzzi was the sole driver to start on 'hard' tyres, although Sutil switched to hard tyres as he stopped on lap one for repairs.

With the increased heat and extra rubber on the track, the 'hard' tyres worked well in the last stints, to the surprise of most teams who expected to see a drop-off in pace and accordingly ran a long middle stint to reduce the last stint to a minimum.

Team by Team

Renault

After poor showings in the opening pair of races, Renault are proving less competitive in faster corners. Heading to Bahrain the team were optimistic that the car would be better suited to Sakhir's lack of fast turns but instead continued their disappointing performances, which were multiplied by race strategies that sent the cars out with heavy fuel to the detriment of the rear tyres.

Trying to analyse their problems is difficult, but you could summarise that the problems of excessive rear tyre wear and their struggles in high speed corners, suggest a lack of downforce is at issue.

However, the two reported problems could be two separate and unrelated issues; this proves that the situation is more complex than it externally appears. Thus the speculation that the team need to develop a long wheelbase B-spec car is overly simplistic.

Ferrari

As in Malaysia, the team are feeding through small developments onto the race car. Revised sidepod flip ups in Sepang were joined by new detailing in the bargeboards in Bahrain. The team removed the flip-up at the trailing edge of the boards and added a slit, similar to that used on their rear wing endplate. The slit bleeds high pressure from outside the board to inside (as shown by Yellow arrow) this reduced the vortex produced at the end of the board.

In terms of pace, Ferrari matched McLaren once more, unhindered by bad starts and Kimi's suspect engine. However, the team are believed to be marginal on cooling and the upper faces of the sidepods were crossed by several large louvers, although the chimney continued to be run closed.

These openings must be costing Ferrari drag, but their straight-line speed continues to be unmatched. This suggests that in the cooler climes of Europe, Ferrari's peak speed will be even higher due to the openings being closed off, added to the advantage Ferrari has in braking and traction, which is important for the shorter European tracks.

Offsetting this potential is the apparent inability of the Ferrari's aero to work in traffic. Several rival drivers have noted the car's sensitivity when following another car. If Ferrari's aero has to work in clear air then this bodes badly for future development. This must first seek to make the car more consistent in all conditions, before developing more efficient designs.

McLaren

McLaren's 2007 season started early, with the team's focus on the new car starting so much earlier than normal. But the design and race engineering teams weren't able to run with their new drivers until the car was ready for initial testing. Thus the work to date has had to both understand the new car and the driver's requirements from it.

Feedback from within the team suggest that Alonso's technical ability, matched to his ability to put in fast times from a less than perfect car have reaped major rewards. The upcoming four-week development phase before the Spanish race should be especially productive for McLaren as the team are already announcing "significant" upgrades for Spain.

As much as McLaren have developed a good car, their understanding of the new Bridgestone tyres also puts them ahead of the other previously Michelin shod rivals. But they are still learning as their pace on the harder tyres later in the race proved.

Due to its long gestation period, the car features so many details in its mechanical and aerodynamic design that several pages could be dedicated to each corner of the car.

One of McLaren's aims with the new car has been to capitalise on every possible bit of space when creating aerodynamic devices, and the diffuser, with its extra channel running above the side diffuser, is stretched to meet the very limit of the bodywork rules, creating a wider duct than other teams have been able to exploit. The inboard ends of each wishbone are lengthened to created aerofoils sending their wake more efficiently to the rear of the car.

Because of this, their bargeboards are more complex than any other teams, sticking to the trusted principal of one larger board, aided by forward-mounted vanes projecting from the keel area. In amongst these vanes are shaped areas of floor and fences to direct the flow around the car and, more importantly, to distribute pressure underneath the car to make the diffuser work better.

One device added this year is the fence running alongside the Splitter (yellow), as used by Williams this year. This device sits behind the front wheel but within the width allowed for the step under the car. This allows the fence to be as low as the floor of the car, which makes the fence very efficient. It drives air along the step under the car and this powers the complex diffuser more effectively.

Toyota

Despite a strong end to the year in 2006 on Bridgestone tyres, the opening races this have exposed problems for the team. Central to their problems are the way the car uses its tyres, as it's inherently too light on the tyres. This makes the tyres slow to warm up, but more durable over the race.

But with such a competitive midfield the poor qualifying performance is hampering their race. In both the last two events, the Toyota cars have been fast on a clear track only to hit the usual overtaking problems. What causes the tyre problems is not clear. The team have announced new suspension developments as well as revised aero, but they are staying tight-lipped about the nature of the changes.

They also have a bigger aero upgrade planned for Spain. Unusually Toyota ran both a low and higher downforce set-up in practice on Friday. The slimmer front wing and "V" shaped rear wing formed the lighter downforce set up, while deeper front wing and rear wing were joined by extra winglets in the sidepods for the high downforce set up. The team settled for a compromise in the race and did not run the sidepod winglets.

Bahrain saw the usual opening added to the engine cover for cooling, while the detail of the floor shows a new approach to the splitter section. Behind the two layer bargeboards, Toyota have added a complex shaped floor extension.

This area is often used by the teams to manage the flow from the splitter and how much of it goes under the car. Toyota's approach is to make the trailing edge of the floor extension serrated (highlighted in yellow), this breaks up the vortices shed from the rear of the floor into several less powerful trails to improve the pressure dispersal across the floor.

Honda

Due to the team's problems with stability under braking, the Bahrain track was never going to suit the car. The numerous heavy braking zones are critical in setting a fast lap and the driver's lack of confidence in the cars handling is shown up even more. The team are working on developments to resolve the issues.

The team's engineering director Jacky Eeckelaert told autosport.com: "We are still investigating the rear end stability problems, and our main focus is on the aerodynamics - both front and rear."

This work centres on how the race car relates to the wind tunnel results. Honda now have their new tunnel in operation, and this is a larger and more complex tool than the simple open jet facility used to date, with the ability to run a full scale car in the new tunnel.

Eeckelaert continued: "We are also investigating other aspects of the car as well, by means of data analysis and comparing the model to full scale wind tunnel data and against the track data, including performing specific track sequences and runs during the normal testing."

By doing this, the team can see where the car deviates from the wind tunnel data. Of course finding the problem is only the first step - and designing and testing a solution is the next. Already the car has raced with a new front wing in Malaysia, while the front wing fins and rear winglet, said Eeckelaert, were "part of the overall aero kit from normal aero development for better efficiency and more for air flow conditioning than downforce."

BMW Sauber

The huge amount of revisiting basic design concepts and proving them with CFD has paid off for BMW Sauber. The car has the best pace of the midfield and challenged the top two teams in Bahrain - but as winter testing proved, the reliability of the new seamless gearbox is still suspect. So far, the car has worked well with the fast and high efficiency tracks at Malaysia and Bahrain.

As with last year, and aided by a new rear wing, the car appears to have prodigious straight-line speed. But, if the car doesn't have the downforce to match the tyres on the slower European tracks it might struggle. Again running with the shorter chimneys in Bahrain, the team's technical director Willy Rampf told autosport.com: "The new chimneys are similar in the outlet area, but influence the flow to the rear wing in a different way to improve the car characteristics like yaw sensitivity."

Williams

As with Toyota, Williams' car is easy on its tyres and this hurts their qualifying pace. While the car's pace is a transformation from last year, several niggling reliability issues with the gearbox surfaced in Bahrain, as well as Rosberg's race engine suffering a water leak.

How the team develop the car in the upcoming tests will be interesting. The car appears to have the potential for a lot of downforce from its complex but streamlined aero, and if the team can turn this efficiency into downforce and improve their one lap usage of the tyres, then they should have a strong mid season run.

Red Bull

Bahrain confused the picture we have of the Red Bull car. So far, the chassis has delivered very little of its potential but the strong race showing from Coulthard is in contrast to the background rumours suggesting Red Bull have a car problem.

The Newey-designed car had a long design period and this may have frozen some elements early in the design phase, before the tyre rules were full resolved, while the all new design has needed time to understand and capitalise upon. The detail aero work is starting to emerge, however, and a more major upgrade of the car may still be in the pipeline.

New pod wings and mirrors appeared in Malaysia, and the team's technical director Mark Smith told autosport.com the developments were "a natural progression from the race one aero package that we first ran in the Magny Cours test," explaining that the mirrors being moved as a result was for two reasons. "We moved them due to the pod wings, but also to improve the drivers' rear view vision," he said. "The current mirror configuration is an interim solution. The aero effect of these mirrors downstream is negligible."

Spyker

With the new aero package only having the mileage from the Malaysia weekend, the team were expected to go better in Bahrain. On closer inspection the upgrade bears even more of a resemblance to the Toyota set up than covered in the Malaysia technical review. Both the front and rear bargeboards also feature an extra vane fitted to their inside face. This is a feature only previously seen on the Toyota since the German GP last year.

The resemblance is only partially acknowledged by technical director James Key, when commenting on the development. "Obviously Mike has had an input into this work," he said. "But so have the aero teams at Brackley and Aerolab, so it is a combined effort as indeed future developments will be. Aerolab has obviously used their past experience in certain areas though."

Yet, in the illustration, the team's independent thinking on the vane (yellow) attached to the rear brake duct is clear - the large duct sports a vane to send flow around the inside face of the rear wheel. Again, Key comments: "This is a sensitive area and the brake ducts can have an effect on flow through the 'coke' and out of the diffuser."

Key also explained the diffuser has been revised, adding: "The shape is new, with the addition of a fence. Only the rear of the floor required modification, so there has not been a substantial revision of the floor moulding. The results are a balanced and efficient gain in downforce, so gains have been found at both ends of the car."

Toro Rosso

Despite running the same chassis as Red Bull racing, Toro Rosso have yet to appear with the same aero updates as the Red Bull factory car. They also have a slightly different gearbox, not featuring the seamless shift, although the same basic gearbox can be run in both modes, albeit the conventional shift is only 1.5 kg lighter.

Even with these changes, the Toro Rosso team are struggling for pace more than the factory team, which is at odds with the obvious sharing of data at the design stage. This raises the question of how much interchange goes on during and after the race weekend, if what was the old Minardi team do not have the same data and knowledge as the factory team they have at least a year of experience to build with such a different car to that run in previous seasons.

Super Aguri

Flashes of great speed and some good race performances underline the basically solid car the team are running. Despite its links to the RA106 Honda, the car appears stable and fast. Some Bridgestone tyre knowledge may be helping the team, but their race pace has been somewhat slower, suggesting they have opposite tyre problems to other teams, where the car runs well on a single lap but less well on longer runs. Unfortunately, Honda reliability let them down badly in the Sakhir race.

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- The Autosport.com Team

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