The ex-Formula 1 and current IndyCar star is making his IMSA SportsCar Championship debut this weekend with the Iron Lynx team in the GTD Pro class, sharing a Lamborghini Huracan GT3 Evo2 with Mirko Bortolotti, Andrea Caldarelli and Jordan Pepper.
It follows the news last month that Grosjean will be part of the Italian brand's twin attack on IMSA and the FIA World Endurance Championship with a brand-new LMDh contender in 2024.
Looking back on the build-up to his first sportscar race since he raced the Matech Ford GT1 in the FIA GT1 World Championship back in 2010, the Frenchman said he feels increasingly at home at the wheel of the Lamborghini.
"There is a lot of adaptation I had to do with the car because it’s fairly different from what I’m used to," Grosjean told Autosport. "I didn’t know the track or the car, but my team-mates have been amazing and have helped me a lot.
"They gave me a lot of driving time the last two days to help me get up to speed. [On Friday] morning I did a really good laptime.
"I still have to understand a few things, especially the ABS is a bit different to what I’m used to. I’ve been adjusting to that, but I’m happy with where we are."
Lamborghini struggled in qualifying in last weekend's pre-event Roar test, with the #63 Iron Lynx car placing sixth in the GTD Pro class and 14th overall among the GTD cars, over two seconds down on the pole-winning Mercedes-AMG GT3.
However, Grosjean remains optimistic that the Huracan GT3 Evo2 will be more competitive in race trim.
"I think the BoP is not the best for us, some cars out there are faster, but you can only control what you can control," added the Frenchman. "We have a really good setup for the race, the other drivers seem to be happy as well.
"Iron Lynx has done a good job to get this new car ready in a short amount of time. The car has been reliable so far. Hopefully we can get through the first 22 hours without any trouble and push for the last two."
"Qualifying didn’t go as we really expected, we don’t really know the reason why, but [on Friday in practice] we had a good feeling that we also had in the Roar," Caldarelli told Autosport.
"Still we have a few bits and pieces that we have to put together to find some performance. It’s a brand new car so we had some issues in Practice 1 [on Thursday], which we fixed, and now we have run without issues."
Caldarelli was reluctant to criticize the BoP with the brand-new Huracan GT3 Evo2, but conceded that Mercedes, which swept the top four positions in GTD qualifying, appears to be the marque to beat.
"We saw a very good pace from them, not only in qualifying but also in race sims," he said of the German marque. "For us in GTD Pro, Mercedes will be one of the benchmarks.
"But I see a couple of other manufacturers that can be really strong, like Lexus. It’s going to be a very tough race again this year."
