Audi is facing an uphill struggle to produce an engine competitive enough to take on Formula 1's long-established main players.
That is the view of former driver Christian Danner, who warned those who are excited about the now-confirmed 2026 entry of the VW-owned marque.
"How realistic is it for them to make such an engine and also take over a Formula 1 team?" he told Sport1, referring to Audi's reported plans to buy 75 percent of the Swiss-based Sauber team that currently races as Alfa Romeo.
"The question is whether it can be done at all nowadays with all the restrictions. In any case, Audi is very ambitious," said Danner.
Interestingly, while the Audi-Sauber plan will involve the German manufacturer producing its own engine in Germany, fellow VW brand Porsche has quite different plans.
However, Porsche's expected 50 percent buyout of Red Bull has been delayed for now as the Austrian team expressed reservations about the influence its new works partner would have.
And if a deal is not ultimately struck, Porsche's 2026 entry could be completely thwarted as the plan was to team up with the newly-established Red Bull Powertrains subsidiary, which has already amassed a staff of 300.
Team boss Christian Horner thinks Red Bull is able to go it alone without Porsche, having already fired up a 'Red Bull Powertrains' power unit at the new factory.
He cast doubt on Audi's ability to do the same.
"It was important for us to get that first rung on the ladder, so it was a historic moment for the company to see the first ever engine fire into life just prior to the summer break," said Horner.
"But there's still a long, long way to go in terms of manufacturing capacity, etcetera, etcetera. And there are timelines for that to be in place, some of which are a slightly unrealistic.
"As a newcomer, I think it's a huge challenge. I mean, it's massive when you look at the current incumbents that we're competing against - the longevity, the continuity that they've had.
"Of course, a company like Audi speaks for itself. But the scale and the size of the challenge, as we've seen ourselves at Red Bull, is enormous - especially when you're starting from scratch." body check tags ::
