The privateer pace mystery that has Toyota puzzled

"What is going on with the LMP1 privateers? Why are they so slow?" Those were the questions Toyota was asking after the official pre-race test for the 2019 Le Mans 24 Hours last weekend.

Everyone was slower at the test day on Sunday than 12 months ago because it was much hotter, but Toyota expressed surprise that the Rebellion and SMP squads, the independents most likely to be nibbling at its heels next week, were significantly slower than one year ago when, to its mind, they damn well shouldn't be.

That's because since the last edition of Le Mans, the privateers have been given a helping hand under the Equivalence of Technology, the means by which the rulemakers are attempting to make sure there is something approaching a genuine battle at the front of the World Endurance Championship. And then there's the year's worth of development Rebellion and SMP have put on what were more of less brand new cars this time in 2018.

The privateers are now allowed to use more fuel per lap and the normally-aspirated cars, Rebellion's eponymous Gibson-engine R-13 included, are also running lighter. Yet the fastest times by a Rebellion and SMP Racing's BRE Engineering BR1 were more than a second down on last year, much more than a second in the case of the former.

Sebastien Buemi topped the times on a 3m19.440s, which was just four tenths slower than Toyota's best from the test day last year. Andre Lotterer's Rebellion mark was 3m21.323s, 1.7s down on the 3m19.680s from Thomas Laurent 12 months ago and Stoffel Vandoorne got down to 3m22.061s, still 1.6s shy of the best lap set by Vitaly Petrov at the test in 2018.

"If you look at last year's lap times, it is a bit difficult to understand," said Toyota Motorsport GmbH technical director Pascal Vasselon. "But this is not a question for us."

The reality is that there are any number of factors why Rebellion and SMP were further away from last year's pace than Toyota.

Buemi's quick time was set during a tyre test, which meant he was on fresh Michelin rubber. Lotterer and Vandoorne posted their quick times on older tyres.

Perhaps more pertinent is that both Rebellion Racing and SMP were running an aerodynamic package that was in some way new to Le Mans. The Swiss entrant had a new lower-downforce package first tried in testing at Aragon in April and then used in opening free practice at the Spa WEC round last month. SMP was running without the extra drag that it loaded on its Le Mans bodykit last year in the wake of Matevos Isaakyan's aerial accident at Spa.

"We are going to be quicker than last year. Are we going to be at the level of Toyota? We don't know" Gaetan Jego, technical director at BRE operator ART Grand Prix

Toyota, by contrast, pitched up with a car in the aero configuration that it ran last year and could hit the ground running. SMP, in particular, was clearly experimenting with different downforce levels over the course of the day.

Neither Rebellion nor SMP was focused on setting quick times on Sunday, though it would not be correct to say Toyota was either. Everyone had their test programmes to get through.

"We weren't focusing on times; we were focusing [on] getting a comfortable car for the drivers," said Rebellion team manager Bart Hayden. "We had the new aerokit to run and it did what we wanted it to do."

The R-13 has shed downforce for Le Mans 2019, but this is not aimed at gaining outright lap time, explained Hayden.

"We've gained top speed and lost a bit in the Porsche Curves and Tertre Rouge," he continued. "It's a trade-off and we're looking more for a benefit on the averages rather than over one lap. The challenge for the drivers last year was getting past the LMP2s on the straights and the new kit addresses that."

Put simply, Rebellion wants a better car in traffic, one that isn't bottled up behind the LMP2s in the corners because it can't get past them on the straights.

Hayden reckoned Rebellion's deficit to last year was in line with the inferior track conditions. He pointed out that the LMP2 pace was 1.3s down, offering a good yardstick because those cars are in the same configuration as last year.

SMP has revealed that it opted for a cautious approach last Sunday.

"We have had a lot of crashes with this programme and we gave our drivers strict instructions not to crash," said Gaetan Jego, technical director at the ART Grand Prix squad that runs the BREs. "You can say that we were conservative during the test. If you put this factor together with the track conditions, it is easy to understand that we were not sandbagging."

Exactly how much the privateers should have gained with the EoT changes, most pertinently the increase in the rate of fuel flow from 108kg per hour to 115kg, is disputed. Toyota puts it at 2.45 seconds. Rebellion and SMP beg to differ.

Jego wouldn't put a firm figure on what SMP believes it has gained with more fuel for its AER turbo V6. He suggested it was some way down on Toyota's estimation but still "more than tenths". Hayden said that for Rebellion and its normally-aspirated Gibson V8 it was difficult to quantify.

"We shouldn't forget that we are running an engine that was developed for 108kg/hr," he explained. "Just because we have extra fuel doesn't mean we can use it. We are getting to the point with the hardware where there are limited returns."

It can be expected that Rebellion and SMP will go quicker in qualifying than last year, and the Russian entrant is predicting significant gains come next Wednesday and Thursday.

In 2018, Stephane Sarrazin posted a 3m19.483s in opening qualifying on Wednesday to put the #17 BRE fourth on the grid when the track was still relatively green. The team then concentrated on its race preparations: the late arrival of race parts meant they had to run-in during qualifying.

"We are going to be quicker than last year," said Jego. "Are we going to be at the level of Toyota? We don't know."