Toro Rosso technical director James Key says his team has a "heavy responsibility" to help its engine partner Honda make progress this year.
The new partnership was born out of McLaren's decision to split with Honda last year and has made Toro Rosso a works team for the first time in its 13-year history. During its first week of testing the new partnership resulted in a marked improvement for Honda over the last three years of its turbo-hybrid project, with no major engine failures and the most mileage of any team.
Toro Rosso has completely revised its gearbox and the rear of its chassis to accommodate the Honda power unit, which requires different packaging to the Renault due to its split-turbo design. For a relatively small outfit like Toro Rosso the change has made for a busy winter.
"I think what we've found with the Honda engine installation is that it's fundamentally different to Renault's -- there's no commonality possibilities there really," Key said. "The chassis design is obviously different, the gearbox is different as well. It's all been done by us in that respect.
"The other thing is that it's a works deal, it's a proper combined effort. There's all the dyno testing, R&D rig testing, joint-development and design work, design work for next year is already underway so all of that is very unique to our relationship to.
"It's a heavy responsibility all that actually, we're looking forward to it, it's a very positive pressure but it's a big responsibility to provide the level that Honda need to progress as well with the team they're working with. It's less opportunity for commonality definitely."
The Honda works deal has offered Toro Rosso extra resources, but Key said it has also come with extra workload that his team had never previously experienced as an engine customer.
"You kind of dream of all of this stuff and then when it all arrives on your doorstep you're like, 'Jesus there's an awful lot to do here!' We began rig testing of certain engine relating systems on the chassis side back in November. We were dyno testing the gearbox in December and have been ever since, both in Milton Keynes initially and Japan as well, so we've got gearboxes in Japan and Milton Keynes too.
"We've been able to do some cooling system tests and so on. That's where that pressure comes. It's when you've not done that in the past, while it's a great opportunity to do it it also puts the team under that added pressure of substantially more parts to manufacture, engineering support, not in Italy but around Europe or in Japan.
"There's quite a bit of added workload for that but it's all for good reasons and certainly Honda needs to have that close relationship with the team to see through those aspects. Gearbox is fundamental for the engine supplier, for example."
But having worked with Honda since the deal was announced in September last year, Key said it was no surprise to him to see the Japanese manufacturer make a smooth start to pre-season testing last week.
"I think if we looked at the situation last year it's a bit of a surprise, but having worked with them for a while now it's less of a surprise. I think looking at the facilities that they've got and the desperate will that they've got to make it work, it's less of a surprise to me now. But obviously you never know until you hit the track and I have to say -- touchwood -- there hasn't been any major issues at all.
"Any minor stoppages we've had have been on our side. They've just been super smooth to work with, we're very inclusive so they attend all our meetings and all that sort of thing so we all know what's going on, and we're working together with them on optimizing everything. So it's been very, very smooth so far and I'm sure that will continue."