BMW Sauber duo Nick Heidfeld and Robert Kubica will have to wait another two months before driving competitive cars again.

At the start of the year the team believed they would be serious contenders for the Formula One world titles, building on their year-on-year improvement over the last few seasons.

But a failure to get to grips with the new rules that came into force at the start of the campaign has culminated in a woeful year to date.

Heidfeld and Kubica have collected just eight points between them, with the former conceding there is little hope of improvement on that until the Singapore Grand Prix at the end of September.

That is in contrast to last year's title rivals McLaren and Ferrari who have slowly but surely found a cure for their ills.

"It seems like McLaren have made a big step, especially at the last race (in Germany), whilst Ferrari made a big step a couple of races ago (in Britain)," assessed Heidfeld.

"We made a big step in Barcelona, and since then it has been a bit up and down.

"I hope we can get to a stage where we can also say we have made a big leap forward, and I hope this might be the case in Singapore.

"We're expecting a lot of new things, and I hope it will move us forward.

"Before then we have another package in Valencia, but my hopes are more for Singapore.

"It is too long to wait, but there's nothing we can do now."

Given BMW Sauber's woes this season, there is every possibility Heidfeld and Kubica will be at the back of the grid in Sunday's Hungarian Grand Prix.

"As we knew a couple of weeks ago, we don't have a lot of updates here, with the next big one planned for Valencia," added the 32-year-old German.

"We do have a new front wing here, which is good because it wasn't planned, and some other minor updates.

"But it might mean it will be a more difficult weekend for us as some other teams have bigger updates here."