Can Porsche survive as the LMP1 hunted?

Porsche introduced an all-new car for 2015 and leapfrogged the updated machinery of the opposition to win the World Endurance Championship. Twelve months on, the roles are reversed.

A revision of the LMP1 hybrid that claimed the drivers' and manufacturers' titles, not to mention the Le Mans 24 Hours crown, will carry Porsche's hopes from this weekend's season opener at Silverstone. Rivals Audi and Toyota have gone back to the drawing board in their respective attempts to get on terms with the defending champion.

Porsche jumped to the front of the LMP1 pack with the second-generation 919 Hybrid, a complete redesign of the 2014 original. This time around it has opted for what Mark Webber, who won the last year's WEC drivers' crown with Timo Bernhard and Brendon Hartley, describes as a "heavy massaging" of its predecessor.

There was always further room for improvement in the 919 concept, reckoned former Porsche LMP1 technical director Alex Hitzinger.

"We knew there were big gains to be made with our package and we knew where they were," he said prior to his departure for pastures new, outside of motorsport, at the end of March.

The basics have remained the same - V4 petrol engine, two hybrid systems and battery energy storage - but there have been developments right through the car. Little save for the monocoque has been carried over from last year's 919, according to Porsche LMP1 team principal Andreas Seidl.

"There have been updates on the aerodynamics, the suspension, the weight and the hybrid system," explains the man who has assumed Hitzinger's responsibilities, at least temporarily. "We have improved the engine in terms of combustion, gas exchange and frictional losses."

The gains made with the two-litre, single-turbo V4 have regained some of the losses that have followed a reduction of the fuel available to each car over each lap in P1 this year. Exactly how much of the 7.5 per cent cut has been clawed back, Porsche isn't saying. But then nor are its rivals.

"We believe we have made a good - or let's say reasonable - step from last year," continues Seidl. "We are convinced that we can be competitive with an updated car, otherwise we would have made a different decision."

WHAT HAS AUDI DONE?

Gone radical, that's what. The aggressive aero treatment of the latest car to be called the R18 e-tron quattro is a direct reaction to the new fuel rules.

The aim with its all-new WEC challenger is simple, according to Audi Sport head of engineering Jorg Zander: "We wanted to maintain downforce at the levels we had last year and reduce the aerodynamic drag."

To achieve that Audi has picked up the nose and moved the monocoque and driver backwards in the name of improved airflow underneath the car.

"We want to make sure we have a smooth flow to attack the underfloor and the rear diffuser," explains Zander. "You can say that we are trying to generate more downforce in the lower parts of the car."

At the same time, it has abandoned the flywheel energy-storage system of previous R18 hybrids in favour of similar battery technology to that pioneered by Porsche. That was part of its strategy for moving up a hybrid sub-class, from four megajoules to six.

This is the optimum class for a turbodiesel, claims Zander. Developing a diesel-powered car to run in the highest, 8MJ sub-division would not be possible within the weight limit.

Audi may have moved up a division, but it is still relying on one energy-retrieval system. Its rivals each have two means of recuperating power, whereas the new R18 does it all through a front-axle KERS.

AND TOYOTA?

It hasn't just built an all-new chassis in the TS050 HYBRID, it has produced an engine from a blank sheet of paper as well. Out has gone the normally-aspirated V8 that powered its previous P1 hybrids to be replaced by a twin-turbo V6.

Toyota opted to switch engines in the wake of its trouncing at the hands of its rivals at the Spa WEC round last May. It was originally on course to make the swap to a turbo in 2017, but believed it had no choice but to accelerate the move.

"We have undertood after Spa that we should have changed engine concepts for '15, because the development rate and the development potential of a turbo is a bit higher," explains Toyota Motorsport GmbH technical director Pascal Vasselon.

"A turbo gives you peak efficiency in a much wider rpm range, atmospheric pressure range and temperature range. Overall you operate at a higher average fuel efficiency over the course of a season."

Toyota has also moved to a battery to store its hybrid energy, abandoning the supercapacitor of the TS050's predecessors. This was always on in the plan: its original road map called for the introduction of the battery in 2016 and the new engine in 2017 to spread the financial burden.

The development of a battery has crucially allowed Toyota to follow Porsche into the 8MJ class. Its hybrid powertrain is still distinct from that run by the reigning champion, however.

Porsche retrieves kinetically from the front axle and via an exhaust-driven turbine. Toyota has maintained the twin front and rear-axle KERS systems of the TS040 of 2014-15.

CAN AUDI AND TOYOTA LEAPFROG PORSCHE?

Porsche was the newcomer in 2014 and clearly had the most to gain for '15, especially when it became clear that it was producing a new car. The group that had designed the first car needed a second stab at it, reckoned Hitzinger.

Yet much of Porsche's superiority over the second half of the season came courtesy of the regulations. Its move from the 6MJ to 8MJ class offered an advantage enshrined in the rule book. The higher the hybrid category, the greater the amount of overall energy afforded to the car per lap.

Toyota and Audi have effectively caught up with their respective jumps in megajoule class. That means there is no leapfrogging to be done, at least under the regulations.

WHO IS BEST PREPARED?

The official WEC test at Paul Ricard last month, the so-called prologue, suggested Porsche was ahead of the game as winter testing drew to a close. The latest 919 dominated, topping the times in each of the five sessions over two days and ending up eight tenths up nearest-rival Toyota.

Porsche was undoubtedly best prepared for the official test. It had been running key updates, namely the revised front suspension and the 2016-spec engine and hybrid system, since the end of last year. It also arrived in Ricard on the back of a 30-hour endurance run at the same track the week before.

That preparation contrasted with that of its rivals.

Toyota had completed four tests with the new TS050 prior to the prologue, but two of those were undertaken with the old V8 in the back of the new chassis. The long lead times for gearbox manufacture meant the new transmission wasn't ready in time, forcing its hand on the engine if it was to get the new car up and running.

Audi had what by its own admission was a difficult winter. It never divulges exactly what it has been doing, but a fire at the first major test for the R18 at Sebring in December resulted in the loss of valuable track time and it attended another test at Ricard in the new year with last year's car.

The prologue, however, was a month ago, and all the P1 manufacturers have been out testing since. And Toyota and Audi have been the ones with the most to gain in the weeks leading up to Silverstone.

THE PROSPECTS FOR SILVERSTONE

Porsche's chances at Silverstone should be stronger than 12 months ago. The second-placed 919 Hybrid might have been part of arguably the best battle of the 2015 season together with the winning R18 e-tron quattro, but the reality was that its rival held a clear advantage. The Audi would have finished at 30 seconds ahead but for a late stop-go penalty.

Porsche went into last season with one hand tied behind its back courtesy of its heavy focus on Le Mans. That meant there was no bespoke high-downforce configuration for the 919 at the start of the year. The result was that the 919 was light on downforce for the high-speed Silverstone Grand Prix Circuit.

This time around, the two Porsches will run in a configuration favourable for the Silvestone 'quickies' such as Copse and Becketts. It will run an update of the bodywork spec, known internally as 'kit 5', which changed the dynamic of last season's WEC when it arrived after the post-Le Mans break at the Nurburgring.

Silverstone might be the toughest track of the season for Audi. There are few heavy braking zones for the new R18's single hybrid system to charge the battery. Audi doesn't deny that it sometimes struggled to recuperate the full amount of energy allowed to it last year, and if there is one circuit where it might struggle to do so again, it is Silverstone.

Zander describes Audi's hybrid set-up as "the most non-compromised solution, considering the whole season and in particular Le Mans". That is just one reason why the championship opener on Sunday might not necessarily offer much in the way of a form guide to the 2016 WEC.

Remember last year, and Toyota's performance on the way to third place on the same lap as the leaders. The updated TS040 didn't look as uncompetitive as it would over the rest of the season.

Expect round two at Spa to provide a clearer picture of what is to come. You can expect Porsche to hit the ground running at Silverstone this weekend - just don't read too much into its performance.