HRT boss Luis Perez-Sala believes the team's F112 car is at 50 percent of its full potential after the halfway point of the 2012 Formula 1 season.
The car was not tested properly before the start of the season, and both cars failed to qualify for the first race of the year in Australia.
However, since then the team has been able to make all the races and even fight with direct rival Marussia.
Although Perez-Sala concedes the car's birth was a difficult one, he reckons there is still a lot to come from it.
"I think that, overall, the F112 is a car that has given quite a good result, keeping in mind how it started," said Perez-Sala. "In winter I had a lot of doubts, because the car was handed to us and we didn't have enough time to review it.
"The proceedings and deadlines weren't the usual ones and that forced us to go quicker to make up for lost time and organize the different parties implicated in the project to complete the car on time.
"But even with all these obstacles, the car has given good results. It has a good base and that's its biggest strength. It's a reliable car with good mechanical resistance and it offers a lot of possibilities for its development.
"I'd say we're at 50 percent of its potential and we can still extract another 50 percent, mainly in aerodynamics."
Perez-Sala said the car will have new developments for the Singapore Grand Prix at the end of September, admitting it is impossible for the Spanish squad to bring updates faster.
"We have some upgrades prepared for the Singapore Grand Prix," he said. "As a small team we can't afford small upgrades every two or three races because the cost of an upgrade or creating a new piece for a small upgrade is very high.
"Besides the aerodynamic study, you have to produce the parts and that also implies a lot of time. So we have to make the most of any changes and have a very clear idea of the direction we want to take for those upgrades to be productive."