Toyota do not expect to race a KERS (Kinetic Energy Recovery System) device until the middle of next season, autosport.com has learned, as other teams continue to weigh up whether or not there will be any advantage from using them at the start of 2009.
Work on KERS will accelerate over the winter as teams grapple with the new technology that will hand drivers short bursts of extra power over each lap.
But with the devices currently believed to weigh between 25 and 60 kilogrammes, some teams suspect that the advantage of the extra power boost will be outweighed by the handicap of the extra weight at the rear of the car.
Sources have told autosport.com that Toyota told their competitors in a secret Formula One Teams' Association (FOTA) meeting in China that they were preparing to start the season with a car not featuring KERS.
It was this response that is believed to have prompted McLaren boss Ron Dennis to say in press conference at Interlagos on Friday: "There is one team that does not intend to have it on its cars."
Toyota team president John Howett confirmed to autosport.com that although the Japanese manufacturer would conduct track testing of KERS next January, he did not expect them to race it until mid-season at the earliest.
"We are working flat out on KERS, but our sincere view is that people underestimate some of the major challenges," he explained.
"We will run a car in January with KERS in a monocoque not designed for it, which we could not race, but it will be a test platform - and our gut feeling is that the earliest (it will race) will be mid season. We don't know yet. We are still testing on rigs.
"So it is not that we are not going to race it. Just our position is different from some other teams who believe it will be an instant in."
When asked if the situation meant Toyota would start the season with a monocoque not designed to fit KERS, Howett said: "Fundamentally we will have a car that will run KERS, but it will be very difficult to race. That is all I am prepared to say, and we would have to modify it to be able to race."
Howett said above and beyond any performance factors that may influence his team's decision, there still remained some reliability and safety concerns about introducing the system before it was totally failsafe.
"It is very unlikely that the first race we will have a safe and reliable KERS that will add performance benefit," he said. "I am not saying that after some time it won't, but there are some pretty big issues. Bear in mind batteries have thermal meltdown.
"We believe we have a very good system and we have it under control, but safety is an important issue for us."
The dilemma about racing KERS at the start of the season is further complicated by the fact that next year's move to slick tyres means that teams ideally want as much weight as possible at the front of the car.
Williams co-owner Patrick Head believed that such an issue could force other teams to follow Toyota's lead and delay the introduction of the systems.
"We've got now four grooves in the front tyres, it started with three, and we've got four grooves in the rear tyre," explained Head.
"When you take those grooves out it increases the contact patch area more at the front in relative terms than it does at the back. That is quite likely to cause you to want to run quite forward weight distribution.
"I'm not sure what it's like for other people, but for us, with pretty much all of our ballast taken up with a KERS that we can't really run more forward than the impact area for the side impact test, it's very difficult for us to achieve the weight distribution that we suspect we will need to make a successful car next year.
"I think there will be quite a lot of teams going to the start of the year without KERS fitted on their cars, with a plan to progressively bring it in as and when they feel that it will make a better overall racing car.
"So I think there will be quite a lot of cars in Melbourne that might be KERS capable, designed to take KERS, but might not have it on right at the beginning.
"You have got to remember that the KERS, when you analyse the potential, the difference it makes can be somewhere between 0.1s and 0.3s, perhaps at the maximum 0.35s per lap, putting aside whether it helps you overtake.
"Having your weight distribution inappropriate for the tyres by more than one or two percent will probably make more difference than those one or two tenths of a second per lap.
"So I think we are presented with a lot of challenges and the KERS, to a large extent, is optional. There are a few teams that will treat it like that at the start of the year."
Howett also expressed his disappointment that news of Toyota's plans for KERS had leaked out of the FOTA discussions in China.
"I do resent that people have mentioned that," he said. "It was a genuine meeting of absolute confidence where everybody sincerely explained (their situation) - saying that if we allowed this concession on certain discussions then we want to freeze the monocoque. We said okay, this is our sincere position at the moment."