Kobayashi made the comments after the pair of Toyota GR010 HYBRID Le Mans Hypercars ended up 13th and 15th in the combined times from the four sessions of the Prologue test on Monday and Tuesday at the start of race week for the Qatar 1812Km WEC season-opener.
He explained that Toyota struggled with graining of its Michelin tyres on the smooth surface of the 3.37-mile Losail International Circuit, which was resurfaced for last year.
“It was a couple of frustrating days; we were struggling a lot,” said Kobayashi after his new team-mate in the #7 Toyota, Nyck de Vries, set a best lap for Toyota that was nearly 1.4s off the pace. “We are definitely hard on the tyres — we cannot really manage the tyres.
“I think we are a little bit lost; every lap I am driving differently and I have to apologise to the team because I am driving like an amateur.
“We are having graining, even on the hard tyre. The tyres are giving up so quick: once you overdrive the tyres are done.”
Kobayashi suggested that Toyota, which won the WEC drivers’ and manufacturers’ titles last year, has modest aspirations for the Qatar event. “We are not dreaming of something,” he said.
Toyota Gazoo Racing Europe technical director David Floury explained that the weight of GR010, the heaviest car in the Hypercar field under the Balance of Performance published last week, appeared to be at the root of the graining problem.
“What we are seeing is that the weight effect is underestimated on this track,” he said. “It drives some working points on the tyres that are not so easy to deal with.
“The track surface is in line with some of the recent resurfacing for Formula 1, which is quite specific.”
He suggested that the effect of the weight on the Losail circuit surface was “not linear”, while pointing out that there is a “big disparity in weight” across the cars of the nine manufacturers represented in Hypercar.
That suggests that the Toyota has reached some kind of tipping point with the further nine-kilogramme increase in minimum weight from the 1080kg at which it finished last season to 1089kg.
The new Losail smooth surface has described as “low-energy” by the teams, but the graining effect is caused by tyre slipping or sliding across the asphalt, a phenomenon exacerbated by the weight of the Toyota.
But Floury did not make a call for a BoP change ahead of the start of free practice for the Qatar 1812Km, which begins with two sessions on Thursday.
“It is not the time to discuss the BoP; it is to try to do with the best of what you have,” he said.
The new system of BoP introduced for 2024 has yet to be explained by WEC organisers, the FIA and the Automobile Club de l’Ouest, but it appears there is more scope for change than last year.
Floury insisted that a change between the Prologue and the race “would not be in line with the process” outlined to the Hypercar manufacturers by the FIA and the ACO.
The 1089kg minimum weight of the Toyota compares with 1075kg for the Ferrari 499P LMH and 1048kg for the Porsche 963 LMDh.
The Peugeot 9X8 LMH and the Cadillac V-Series.R are the lightest cars in the field at 1030kg and 1032kg respectively.
Porsche topped all four sessions of the Prologue, Frederic Makowiecki ending up quickest with a 1m40.404s.
That compared with the 1m41.789s Toyota best from de Vries and the 1m42.097s from Brendon Hartley, the fastest time by the #8 Toyota.
