Autosport has reported:

Audi drivers Nico Hulkenberg and Gabriel Bortoleto say extreme heat is exposing a power limitation in the team’s Formula 1 engine, with Singapore expected to bring conditions similar to those that troubled Audi in Malaysia. The pair said the team has identified the issue, while also reporting that its major upgrade package introduced in Baku is delivering the expected gains.

The Marina Bay Street Circuit would, in theory, suit Audi because it is less sensitive to engine power than some tracks. The team, led by Allan McNish, would normally expect to benefit at circuits with lower power demands, but its drivers said the hot, humid conditions in Malaysia and Singapore are creating a separate challenge for the power unit.

“I think we have to be cautious and careful”, Hulkenberg said during his Thursday media session. “I think Malaysia brought some new things to light and these climatic conditions are not so favourable for our PU at the moment. We definitely had some struggles on that side and obviously here it's more of the same.”

As in Malaysia, the FIA issued a heat hazard declaration for the Singapore Grand Prix, indicating that temperatures of 31 degrees Celsius or higher were forecast. Hulkenberg said he expected another difficult weekend, despite the circuit’s layout. “It is a less power-sensitive circuit on paper, for sure, but my personal expectations are not too high for the moment”, the German said.

Asked whether the problem was mainly about cooling, which could require Audi to open more bodywork and sacrifice aerodynamic performance, Hulkenberg said that was not the issue. “No, I think we suffer from power.” The team is therefore losing outright engine power in extreme heat, an assessment Bortoleto also gave.

“Yes, I would say that right now, especially in the last races, it’s our biggest limitation”, Bortoleto said when asked about heat. He described what Audi has built for its first season as “something decent,” and said the team still needs to make more progress on drivability and “the situations of the climatisation that you were mentioning.”

Bortoleto said he trusted Audi to resolve the problems and eventually become the benchmark for engine performance in Formula 1. He pointed to the manufacturer’s results in DTM and the 24 Hours of Le Mans, saying the people in Neuburg had built the best engines in other series in which they had competed.

“If I trust them? Absolutely. I think they can fix it. These people in Neuburg have built the best engines in other series that they have taken part in in the past, and I have no doubts they're going to do the same in Formula 1,” he said. “We just need to give them time. We cannot believe that we would arrive in Formula 1 in the first year and build the best thing ever made. It would make the others look like... I would swear right now, but you understood what I was going to say!”

“So we need to have patience. I believe in the people that are there in Neuburg, and I believe they're going to make something great,” Bortoleto said. His confidence came as the team continued to work on power unit improvements, including drivability and performance in the hot conditions.

Audi has also resolved questions about a major upgrade package brought to Baku. The Baku City Circuit, with its many 90-degree corners, had not provided a representative test, and a difficult weekend there left doubts about whether the changes had worked. Back-to-back tests in Malaysia gave the team a clearer answer and showed the upgrade was a step forward.

“Well, we concluded that it worked. It worked pretty OK, like we expected”, Bortoleto said. “Entry, mid, exit of all the corners, I think we made a good step everywhere. There were a lot of doubts after Baku, because we had a tough weekend, about the package and if it worked or not. But I think now we can finally put a dot on this and say that we are sure that it worked as expected and that things are working in the right way.”

The experience also showed that Formula 1 teams may need time to understand major upgrades and extract their full performance. Hulkenberg said Audi was closer to understanding the package after further sessions, setup variations and comparisons between the track, wind tunnel and computational fluid dynamics, or CFD.

“Yes, we are for sure closer [to understanding it]. The understanding obviously grows and builds with every session you do. You do different setup variations, you scan the delta to map, and in general you build your correlation between the track, the wind tunnel and CFD, so it's good,” Hulkenberg said. “I think there's probably still some bits and bobs to explore and to discover, but it's not like we're going to get another second out of it or something.”