He turned 120 laps of the 1.7-mile short course at Sebring International Raceway, sharing the track only with teammate Ed Jones, and Carlin-Chevrolet’s Max Chilton.
Boisson said that Grosjean had made “good progress” since his previous two one-day tests at Barber Motorsports Park and WeatherTech Raceway Laguna Seca – but also acknowledged the steep learning curve that his new driver faces in the NTT IndyCar Series, despite starting 180 F1 grands prix.
“This series is tough,” Boisson told Motorsport.com, “and no matter who you are, you’re not going to show up as a rookie and just kick people’s ass. Everybody’s competitive and the tracks are very different, you have to learn so many tricks between all those different tires and different tracks.
“That’s why there are really good guys in their 40s who are still performing really well. It takes knowledge, understanding and skills, as well as reflexes and speed.
“So it’s going to be a big challenge at the beginning, the first few races, just because of the nature of IndyCar racing. It’s a very competitive and tough series, because we have different tires, different types of racing, and very little practice.”
Boisson, who last year engineered Santino Ferrucci and before that Sebastien Bourdais, said Grosjean has “been in the gym but we got him pretty tired by the end of the day. He’s good with the heat, but today was 90degF and pretty humid, so that’s definitely tough conditions.
“But since Barber and Laguna Seca, Romain has learned what we have as tools for adjusting the car, what does he like, what does he not like, so it was instructive, a good day.
“We did some fuel saving practice, and because there were only three cars on track we took the opportunity to practice running under yellow [caution], how to do restarts, that kind of thing that he’ll have to do at some point.
“Then, we also did a lot of changes to the car today: different rollcenters, diffs, dampers and did a lot more than even the last test. The last two tests, we didn’t really have a chance to change the diff or do too much with the rollcenter – or not as aggressive as we wanted.
“But since then Romain has been to the simulator so we started working on the whole package, we tried more setups. Today, we said, ‘OK, let’s apply those things we learned [in the sim] and although the car may not be perfect for Sebring, it doesn’t matter because we don’t race at Sebring. Let’s just try stuff, see what it does, find out how it feels.’
“He noticed how rough the surfaces can be. After the first run at Sebring, he came in and said, ‘Yeah, it’s bumpy’, and I said, ‘And you haven’t even been to Detroit yet!’ It’s definitely an eye-opener, how bumpy it is. You have to do some funny stuff to the car.
“But the simulator actually does a really good job including all the bumps and roughness of these tracks. The street races are really hard for a rookie, with no testing on them.
“Sebring represents something similar to a street course for us, but it’s not a street course per se. Some of the corners are a bit faster, some of the corners are less bumpy than the street courses we race on. And this year we’re going to have less practice and that’s going to be hard – two sessions instead of three before qualifying.
“So the Honda simulator helps quite a lot so he can learn those tracks before we get there, and so we can start to play a little bit with the setup for him.”
Boisson said that Grosjean has learned the adjustability parameters of the car, and is now adapting his style to the car, rather than trying in vain to make the car suit his natural style.
“Yeah, he’s definitely adapting himself; he’s a hard-working, dedicated guy,” said Boisson. “He’s been studying data a lot.
“Barber was hard because it was his first time, it’s a tough track and we were not very good there. But by the time we got to Laguna we looked a lot more competitive because he had been able to sit down and look at the data and seen, ‘OK, those guys are doing that, I’m not doing that so I must be doing it wrong, so I need to figure that out.’
“He’s definitely trying hard how to deal with this car because in the high-speed corners, this car moves around a lot more than F1, so he needs to get comfortable with the motions. And he’s spent a lot of time studying videos and data to adapt himself by understanding what the car needs, not what the car needs to do for him.”
Asked how he felt Grosjean’s approach compared with Ferrucci, Bourdais and Alex Palou, who as a rookie last year raced for Coyne, Boisson said that he was “very similar” to Bourdais and Palou.
“Santino was more like a ‘feel’ guy – goes very hard and works from his feel of the car,” he replied. “Alex was very similar to Seb – very hard-working, going through everything, analyzing everything, and what they want from a car was very similar. And Romain is very in line with that: he definitely does a lot of studying, looks at the data a lot, always wants to talk about it. Seb was like that, Alex was like that.
“And so far, I feel like what we did with Alex last year [setup-wise] falls pretty well with Romain. Santino was OK with a lot less rear-end security. Romain is not as picky as Seb [in that area], but more like Alex, somewhere in between Santino and Seb.”
Boisson says that Grosjean is not only working hard at improving himself, he’s also able to deliver a lot of useful feedback to the engineering team.
“Romain has got very detailed explanation of what’s happening in the car, and that’s very important for me at this point, to understand what he means,” he said. “He feels things very well, he’s very detail-oriented and he then gives good feedback of what he’s feeling.
“And now he knows what the limit of the car is and what the tools can do, he’s getting to the point where he can tell you what he wants.
“But still, it’s a lot for him to take in. In one day at Sebring, it’s very easy to get confused. I’ve had that many times at Sebring where you leave the track scratching your head, thinking, ‘What is happening here?!’ but then you go on to St. Pete and think, ‘Huh, OK, we weren’t that lost.’
“He and Ed [Jones] have similar enough driving styles that they can be useful for each other this year – it’s very similar stuff that they like, and then when we try it, they give very similar feel and feedback. Today they diverged a little more, but maybe that was what we were saying about Sebring – it can just be a little strange. I think early on in the season, the setups for Romain and Ed will start off pretty similar.”
Although that was the last time Grosjean drives an IndyCar before the opening round at Barber Motorsports Park on April 16-18, the #51 DCR-Honda will be in action at Texas Motor Speedway on Wednesday, with Grosjean’s oval sub Pietro Fittipaldi at the wheel.