The decision to delay an update centred on a new crankshaft for the 963’s 4.6-litre twin-turbo V8 has been made after discussions with WEC organisers the FIA and the Automobile Club l’Ouest and IMSA in North America, which jointly govern the LMDh category.
The FIA and the ACO demanded that the engine had to come on stream at the Imola WEC round in April in order to assess its performance over the the Italian event and then the Spa race prior to Le Mans on 15/16 June, Porsche’s 963 project chief Urs Kuratle has revealed.
That would have left insufficient time to undertake the necessary endurance testing before the homologation of the engine and to produce a sufficient supply of units for the factory Porsche Penske Motorsport squad and the customers teams.
“We do not do it in Le Mans, a decision is done,” said Kuratle.
“The governing bodies set a clear goal, clear targets how we had to implement the crankshaft and it won’t allow us to do it before Le Mans.
“We said, ‘Okay it is a challenge and we try to do it’, but the risk was too big.”
The timeline presented to Porsche by the governing bodies was compounded by the fact that the Imola WEC round clashes with the Long Beach IMSA SportsCar Championship event on the weekend of 20/21 April.
That meant it would have had to convert a supply of engines for four PPM 963s run across the two series, and the five customer cars from Jota, Proton and JDC-Miller in order for them all to start using the new configuration from the same weekend.
The LMDh ruleset allows for only one homologation, which means all cars have to run the same specification at all times.
Kuratle revealed that the introduction of the latest spec LMDh hybrid system jointly developed by Bosch, WAE Technologies and Xtrac for January’s Daytona 24 Hours, the opening round IMSA round of the season, had eased Porsche’s concerns over reliability.
The key motivation for the engine revision, which does away with a 180-degree or flat-plane crank in favour of one of 90-degree configuration, is to reduce vibration in the name of hybrid system reliability.
“There was a different hybrid version, there was 2.3, 2.3* and now 2.4, and these changes are going in a good direction,” explained Kuratle.
“Our four cars ran with no problems on the hybrid side at Daytona. That fact helped us make the decision.
“We had to decide to concentrate all our endurance runs before Le Mans on the old crankshaft; we would not get enough mileage on the new one.”
Kuratle explained that it is still in the plan to introduce the engine revisions this season, but he insisted a timeline for that had yet to be laid down.
No date will be fixed until after Porsche has gone through its pre-Le Mans programme of endurance testing with the existing engine, he said.
Kuratle did not confirm 100% that the engine update would count as one of the evo joker performance upgrades allowed to each manufacturer over the lifecycle of an LMDh or a Le Mans Hypercar.
He said “it would probably be one” when asked.
Upgrades made in the name of reliability are not limited, but still have to be approved by the rulemakers.
