Tech Analysis: Toyota TF108

It seems every year the Toyota team are optimistic at their launch, and this year was no different in the team's upbeat prediction of what they can achieve in the coming season. What's different this year is that the car looks like a substantial step from its predecessor.

Toyota have followed an evolutionary path since the first Gustav Brunner-designed race car appeared in 2002. During this period the team have appeared step behind the opposition, always seeming to have skipped the critical shapes and add-ons, while optimising their own take on the front wing/bargeboard/sidepod package.

While Toyota did have a period of some success, they have yet to really threaten the established teams, and last year ended as a low point for the team. The TF107 proved inconsistent, and hence did its fortunes.

The Toyota Way

Heading the technical team is Pascal Vasselon on the chassis side, with Luca Marmorini taking care of the engine. This pair have lead the design side of the team since Mike Gascoyne's departure.

They work beneath a sizable corporate structure, and operate without a recognisable Technical director in the traditional sense, but Yoshiaki Kinoshita, in his Executive Vice President role, leads the duo and all technical matters.

Kinoshita comes from a technical background, having worked through Toyota's various motorsport programmes at a senior level. In being a Toyota man, he brings the manufacturer's philosophies to the team - 'Hoshin Kanri', or raising the bar, and 'Kaizen', or continuous improvement, are well-known phrases from the team.

The collected philosphies are termed the 'Toyota Way', which the manufacturer employs to lead the world of production automobiles. The team's President John Howett sees this as a bottom-up philosophy, and not a strict management lead structure.

Either way, the team have been criticised by ex-drivers for their overtly corporate way of dealing with decision making. But f the Toyota Way is the leading marketing message coming from the team, beneath the surface several key signings may start to have a positive effect.

For starters, Mark Gillan has been taken on in the aero department. Gillan came from Jaguar Racing, and is a logical worker who can bring some organisation and discipline to the department.

More importantly, Frank Dernie has been taken on as a consultant to the team. Dernie was one the key figures at Williams in the eighties, and was brought back as a consultant during their problematic BMW period. His joining Toyota can be seen as significant, as the team are perhaps looking to operate more like other F1 teams in some areas.

"He started to work with us in September 2007," said Vasselon. "He is working on some long-term studies, like future regulations and the impact of the regulations on concept of the car."

As an aerodynamicist and one of those responsible for the Williams active suspension, this makes sense. But tellingly, Vasselon added: "He is also an advisor for the senior people of the team".

Clearly, one of the important roles for Dernie is to help fix the way Toyota work as well as aid the actual design of the car.

"He helps especially to build a bridge between the wind tunnel and the track," Vasselon said. "He is there to feed our team with his experience. It is really a very good situation, because he is very experienced."

With the standard ECU, the Toyota steering wheel is much more basic © Toyota (Click to enlarge)

The new car

As in any year, understanding the previous car's failings and assessing any new rules is the first order of work.

The inconsistent handling of the TF107 was pinpointed as an aerodynamic problem. It was a typical case for a current F1 car, where the downforce varies with attitude changes and hence the cars balance is upset.

Rectifying this required two changes. First, a different approach in the wind tunnel, and secondly, fundamental change in the layout of the car.

Toyota have lengthened the car this year, which goes hand in hand with the need to alter weight distribution, but also makes the car less liable to big attitude changes around the lap. Other tea,s have achieved a wheelbase change with longer gearboxes or different front wheel positions, but according to Vassselon, "We've done it at several places; it's not just in one places we've distributed it a long the car."

The figures the team sought in the wind tunnel were not aimed at higher and higher downforce levels, but paying more heed to how much downforce is lost as the car steers, pitches and rolls.

This emphasis on making the car less sensitive would aid the problems of the TF107, but also assist the drivers with the loss of driving aids. Vasselon explained the thinking:

"When you generate wind tunnel results, you have objective criteria to decide what is good, what is bad. What we have done is changed the weightings - we are giving more weight to all that concerns balance consistency and downforce consistency.

"You want to make sure the aero balance and downforce balance doesn't change too much."

In seeking the change in sensitivity, the team have gone for a different aero concept, doing away with the forward bargeboard set-up raced since 2003.

This follows what is now considered the de rigueur set-up for an F1 car, adopting larger bargeboard boards with a smaller array placed ahead of them.

For many years, the difference between forward-mounted boards and larger rear-mounted boards has been debatable. Now it seems that all teams are converged on a similar path. The function of bargeboards goes beyond the old method of routing air around the sidepods; the boards now do more to manage pressure distribution under the car to the diffuser than over the visible upper surfaces of the car.

The new bargeboards (yellow) are the major change in aero strategy © Scarborough (Click to enlarge)

The placing of the boards nearer to the start of the floor appears to create a more stable flow structure than forward mounted versions. Along with Toyota's adoption of this approach this year, Honda are also expected to follow this philosophy in 2008.

In moving to large bargeboards, Toyota have needed to redesign the entire front end of the car. I asked Vasselon whether this meant the wind tunnel projects took longer than normal.

"The schedule has been pretty standard," he said. "We started to run the windtunnel model in March. In fact, the concept change does not mean that you step back hugely."

But the impact of the change affects many parts, as Vasselon outlined:

"The cascade starts from the front wing, going through the wishbones, the turning vanes, the bargeboard, the sidepod and sidepod wing."

Visually the car is very different, the nose tip swept down low over the front wing. Gone is the merged bi-plane wing and nose cone, instead, a McLaren-like bridge wing has been adopted.

The lower front wing is the launch version, and will change. The front suspension picks up the flow, but the sculpted upper wishbone seen last year has also gone, replaced by much simpler profiled arms.

But the biggest change is in the bargeboards; the smaller forward boards nestle under the front suspension and are merged to the monocoque, again like McLaren have done so for many years. The large board curves back over the axe-head, jutting from the floor, and along with the raised monocoque, feeds a large undercut in the sidepods.

A visual novelty was the larger pod wing, now complete with a wing mirror. The pod wing is supported in two places so the vibration that affected other teams' mirrors should be negated. The placement of the mirror in this area has very little aero effect, and serves mainly as a neat packaging exercise.

The sidepods themselves are also much slimmer around the rear end, with water and oil coolers mounted horizontally again in a very McLaren-like set up. This necessitated a different chimney position, but the actual shape of the cooling outlet is very similar.

Around the airbox, Toyota have followed fashion and slimmed the spine, remaining legal by adding fins to meet the minimum dimensions demanded by the FIA.

Other novelties beneath the skin include a new gearbox. This is still a cast titanium case, but the quickshift internals are now an exclusively a Toyota project.

Last year Williams and Toyota partnered on a seamless shift, using Williams' second generation of gear selection and sharing the control system development.

New lower nose and bridge feature on the TF108 © Scarborough (Click to enlarge)

Now, Toyota have diverged from Williams and will solely develop the entire drive train once more. With a shared chassis controller (ECU) last year this partnership made sense, but now each team have just a single ECU to control engine, gearbox and chassis, so the ties were broken to maintain privacy between each team's control codes.

The single ECU (SECU) has been a challenge for Toyota, as it has for all teams. The reduced number of channels the system can monitor and control has forced different control strategies.

More visually, the SECU and its homologated visual display has reduced the Toyota's steering wheel functions too. The new steering wheel is half-bare without its usual large LCD screen and numerous controls.

As the SECU also controls the engine, Luca Marmorini has had the task of leading its integration with the existing engine. The engine freeze prohibits any change to the engines internals, but although frustrated by the restrictions, Marmorini was able to improve the engine.

"We can work on fuel and lubricants," he said. "There are things we can work on. I am surprised we could bring something significant to the car".

He added that to get more performance from the existing engine, previous safety margins had to be slimmed to work the unit harder.

Yet, the work has been largely to get the SECU to replicate as much of the old Marrelli system as possible. This process started with a Marrelli system cut down to emulate the SECU before the new unit was available to start testing.

Marmorini admitted that more engines were needed during the development phase, and that power delivery has been affected.

"In steady state there's no change, [but] in transient we were little bit better with the old ECU," he said.

Thus the car will start testing with the same peak horsepower, but there is still some power further down the rev range that the team need to find within the SECU.