Racing Point should look more competitive at the forthcoming Spanish grand prix.
The Mexican driver says that is because new team owner Lawrence Stroll only took over Force India late last year.
"You have to remember that the team owners changed quite late, so we are a little behind schedule," said Perez.
"But we can catch up," he said in Baku.
Perez said Racing Point is firmly in the midfield, and working hard on a big upgrade package for Barcelona in a fortnight.
"If it works as we plan, we will take a big step forward," he said.
And he said the step forward could be even bigger than a usual Barcelona leap, thanks to the kind of money now being invested by billionaire Stroll.
"I think so," Perez said.
"The weekend in Spain is very important for us. He (Lawrence Stroll) is fully committed to getting better results, and understands that it is a long term project.
"I would like it if in formula one you can change the situation faster, but it just takes time," he explained.
"Look at Renault -- a huge organisation, but they still need time.
"Lawrence is excited, but at the same time patient with realistic goals," added Perez.