The news that the FIA had officially invited expressions of interest for the proposed new 2017 alternative engine sent the Interlagos paddock into a flurry. Rumours and speculation abounded in the confined space, and the topic was the lead item in Friday's team principals' press conference.
To paraphrase former US Secretary of Defense Donald Rumsfeld, when it comes to the alternative engine there are known knowns, known unknowns, and unknown unknowns.
What is known is that since the switch to F1's current hybrid power units, the cost of an engine to a customer team has skyrocketed, and that skyrocketing has led to an era of financial precariousness for a significant proportion of the grid. The current situation is financially unsustainable, and something needs to be done.
Another known known is that even those teams with money to spare - such as Dietrich Mateschitz-owned Red Bull and Toro Rosso - are struggling to secure power units for 2016, partly thanks to recalcitrant manufacturers unwilling to supply strong rivals with their own competitive advantage.
The big known unknown is the specification of this proposed alternative power unit, leading to press room jokes about the return of the Brabham fan car and Flintstones-style foot-powered machinery. The alternative unit will be equivalent to the existing power units, and is rumoured to take the shape of a 2.2-litre twin turbo.
And then there are the unknown unknowns, such as who might supply these proposed alternatives.
That the FIA has called for expressions of interest for the alternative power units this late in the 2015 season - expecting them to be competitive in time for 2017's pre-season testing (and the teams' 2017 car design schedules) - implies that the Federation already has one or more suppliers in mind, companies already working on some form of equivalent engine for the current F1 regulations.
Mario Illien is a strong contender, given that he spent the early part of 2015 working with Red Bull and Renault in an attempt to rectify the ongoing problems with the Renault power unit, while there isn't an engine supplier story in F1 that does the rounds without the Cosworth name attached in some form.
Asked for their thoughts on the proposed alternative power unit during the Friday press conference, the bosses of several of the paddock's customer teams all gave the concept varying degrees of support.
"I think it's a good idea," Franz Tost said. "We from Toro Rosso will support it because we want to have this new engine - at least to have the possibility to choose something, to bring up a new engine for lower costs a) because the current power unit costs a hell of money; b) to be flexible; c) we will have a new sound. And I think that most of the fans and those people here want to have another engine with a better sound - and the rest we will see."
Monisha Kaltenborn gave a more in-depth analysis. "Well, we all know that in the last few years the engine price has been the major cost trigger, driving costs tremendously high, and we are a customer for engines, so what our prime position is that we want the engine prices to go down and we believe there is room to do that," she said. "Looking at this alternative, we are a bit skeptical about this because, looking at other series you see how difficult it is if you have two kinds of different engines in one series. It's not worked in the past. We're seeing it now, currently, that there are a lot of issues attached to it. That's one point. The second one is it's meant to have parity with the current engine and that's a complex area. It's not easy to achieve that.
"Moreover, there's a world out there and we have to move with that world. Hybrid technology, you might like it personally or not - but that is the demand on the market today. So we have to also cater to these demands, particularly the engine suppliers, so I believe it's also not going to be very good for the image of Formula One - we've tried to move away from such technologies which are irrelevant for the businesses of manufacturers. More importantly we actually should try to get the prices down, which in our view is absolutely doable."
Graeme Lowdon of Manor - the team that this season rose from the ashes of a financially-crippled Marussia - was also positive. "I think we need to welcome anything that is designed to make the sport more sustainable and hopefully, as well, put back into the hands of the teams a little bit more about what they can control," he said. "None of the teams here make engines and therefore you can see that there's frustration among certain teams where they don't have the ability to fully influence their position in the Constructors' Championship.
"There's no championship for an engine manufacturer and yet it has such an enormous influence. That said, if there is a dominant engine and you have it in your team, then that's obviously a great position to be in and everybody will be pretty happy with that position. Equally, it there's teams in that position, there's going to be teams in the opposite position. Ideally what we want to see is teams fighting it out on the race track."
Potential suppliers have until close of business on 23 November to register their interest with the FIA. Watch this space...