How Renault is a step ahead in Formula E

Formula E's second season is all about the powertrain. Except it's not all about the powertrain.

Open competition for the championship's second season has brought new solutions for the electric motor, inverter and gearbox packaged into the various cars populating the Formula E grid.

So after a debut season where spec technology was often separated by small margins, Renault e.dams' pace advantage early in season two means all the most obvious conclusions point to a particularly potent new powertrain.

If it were that easy to explain, though, the step Renault's rival Abt Audi Sport made from Beijing (where it was a distant second best) to Putrajaya (where it was almost as fast and won when the favourite hit trouble) would not have been possible.

Di Grassi knows he doesn't have the fastest car in Formula E right now © LAT

Powertrains are homologated for season two. So if Abt's solution was fundamentally less effective, how could it have engineered such a turnaround - one that means it now heads the drivers' and teams' championships - in two weeks?

Were that the case Lucas di Grassi, the Malaysia victor, would not have observed: "We have to understand what we improved and try to do a little bit more to catch up Renault. They are still the car with the highest performance."

The idea of Renault e.dams finding electric racing's silver bullet is far too simplistic. There's an all-round aspect to the team's Z.E.15 that has slapped a target on its back for 2015/16.

"It's not only new technology, the motor and inverter, but also gearbox and suspension," says Alain Prost, e.dams co-founder and FE team senior manager. "It's very difficult to judge how much you gain [from each part]. It's the whole combination. Nobody can say how much is here and how much is there."

The combination of factors led to Sebastien Buemi dominating the opening event in Beijing, and almost repeating the feat in Putrajaya until his car wilted, twice, in the searing heat. Mechanical misfortune aside, the pace advantage of the Z.E.15 has been stark.

Buemi has recorded comfortable pole positions twice now, although in fairness to di Grassi the Brazilian would have been a qualifying rival in Malaysia had he not hit the wall.

Nonetheless, it was a Renault on pole, and a Renault leading comfortably enough, devoid of any energy-management problems, before suffering the first of two software problems caused by the heat.

"Renault have obviously invested a lot of money," says Andretti Autosport team boss Roger Griffiths. "They've taken people off the F1 programme and it shows what a company can do when they've got the resources.

"What they've done is show the cars can be made to go an awful lot quicker."

In Putrajaya we saw how much quicker - 1.6 seconds in the form of both single-lap and race pace compared with season one. And the ease with which Buemi bagged bonus points for fastest lap there, and in Beijing, is also noteworthy.

Beijing wasn't a fair comparison of year-to-year laptimes because the track layout had changed slightly. Last week, though, the step forward was rammed home.

Investing time, money and expertise is the reason that step has been made.

Renault has been responsible for the development, design and production of the Z.E.15 powertrain, with e.dams (or DAMS to anyone who didn't follow Formula E's genesis) taking charge of making those improvements translate to on-track performance.

Paddock rumours put Renault's financial input at around €10million. It's exactly what you would expect from an electric vehicle manufacturer competing in a championship it wants to use as a test bed for road car development.

And given how much Renault spends on an F1 programme currently mired in difficulty, it is returning significant value in terms of on-track success.

Prost thinks there is more to e.dams' success than simply the Renault powertrain © LAT

The impact it has is exemplified by the carbon casing of its two-speed gearbox. It's the sort of important commodity that good backing unlocks, considering the team requires four gearboxes plus spares; another team estimated its own offer of carbon casing to cost at least £250,000.

Weight, always fundamental in motorsport, is particularly crucial in Formula E given the base parts of the spec chassis came in too high in season one. Some new powertrains in season two have proven heavier than others, and getting close to the minimum weight limit has been a challenge - with Renault e.dams one of only two teams to get below it.

Given how heavy the cars are, and their naturally rearward weight distribution, any advantage gained in this area is a significant one.

"We know that all the [chassis] tubs have been carbon for a long, long time in different formulas," says Renault Sport programme leader Vincent Gaillardot. "The casing in the battery is in carbon, and the powertrain. It looked the logical specification.

"We've all known since day one that targeting the weight limit would be challenging and the way we have specified our powertrain, our first priority was to have the weight [as low as possible].

"I haven't seen cars that are overweight performing so well. People had so much focus in Formula E on electric technology they probably missed motor racing's bottom line."

The assumption any one catch-all solution exists in any sphere of motorsport is misguided, which is why putting Renault e.dams' success solely down to its powertrain would be wrong. What it's really done is apply conventional racing logic to an unconventional car and racing series.

"We tried to be more efficient," admits Buemi, "and have done a better job, but it's the whole thing. We worked on every detail we could improve - the handling of the car and the traction - to make it like a proper car now."

Of course the build of the new powertrain is a contributing factor. One of the key requirements was for it to sit lower and help reduce the Dallara-built spec chassis' centre of gravity.

That helps improve traction, as does the work Jean-Paul Driot's e.dams operation has done on the rear suspension.

Manufacturers building their own powertrains were able to make changes based on the gearbox modifications, as long as the suspension retained the twin-wishbone, pushrod set-up.

While this meant the back end of the car, in particular the rear uprights, could be what Griffiths feels is "very different" to season-one configurations, the real scope for improvement comes in the dampers.

e.dams has tried to focus on conventional areas of performance as well © LAT

Damper settings were open before but now the supply is free there is greater freedom over what Driot describes as "how to integrate them within the current chassis you have".

"We are very used to it, and I have very good track engineers," he says.

By using seven-post rigs to optimise those damper settings, and then apply those lessons on-track during tests, e.dams has been able to fine-tune a crucial component estimated to be worth tenths of a second.

"It is a really standout racing development," says Gaillardot. "I can't believe there's some secret."

The upshot is a car that works extremely well, not just a powertrain that is efficient. What was noteworthy about the Renault in Beijing was how comfortably it rode the kerbs; one team boss estimated Buemi and Nicolas Prost were able to carry as much as 5km/h more through the corners.

That mid-corner speed carries onto the next straight, amplifying the advantage. And if you're carrying more momentum out of a corner and have to push your motor less to get to top speed, it will only help with efficiency.

"It's not like our car is a revolution," notes the younger Prost. "Everything is just slightly better."

Positives aside, the talk from the team has been about being wary of the strong start it has made. If its advantage is replicated more often than not, complacency could be the team's biggest enemy, and the Putrajaya problems prove that banking on a Beijing repeat each time would be folly.

"A start like this is very good and bad at the same time," says Driot. "It's good because you look confident and the result tells you about the performance of the car.

"It's bad because we must never think everything is there, that we can go to the next race smoking cigars and being relaxed. That's the worst we can do.

"The others, when they see they are a little bit backward, they are going to work more than we are going to do if we think we are sitting on the top.

"This is why winning like we did in Beijing doesn't matter."