Hulkenberg has shown good pace on his return to a full-time drive in 2023, regularly making Q3 and qualifying as high as second in Canada, before he took a penalty hit in Montreal.
However, the car has inevitably fallen off the pace in races and used its tyres too hard.
In the first half of the season his best result was seventh in Australia, although he also picked up a sixth in the Austrian GP sprint event.
Hulkenberg has said the team knows what it needs to do to improve the car, but stresses that it won’t happen in the short term.
“I think we understand the cause and what happens and why it happens,” said the German after finishing last in the Belgian GP.
“But fixing it and bringing loads of performance, it doesn't just lay on the street, it's a bit more complex.
“I think we can still improve the situation this year. To what extent, that's TBC, it's down to us, and we have to prove it. But yeah, it's a longer-term thing.”
Hulkenberg says the summer break will be useful for the team as it regroups.
“Yeah, we need it,” he said. “But what we really needed is some upgrades, some real performance, to help ourselves. That's what we need.
“Obviously, this track [Spa] again exposes the weaknesses of our car very much. That's why we’ve not been competitive on any session on any lap really, I feel. So, a lot of work to do."
Hulkenberg had what he called a “grim weekend” in Belgium, starting at the back in the sprint after hitting hydraulic issues, and failing to set a time in main qualifying due to the issue not leaving him time to get a lap in.
He took advantage of his last starting spot to take a new Ferrari power unit and gearbox with effectively no penalty, and started from the pitlane for car changes in parc ferme, as he eventually finished 18th.
“It's been a pretty grim weekend for us,” he said. “So, [we will] write it off, reset, regroup and come back after the summer break, hopefully a bit stronger. I've got a fresh engine now. So let's see how far that takes us.”
The only bright moment in his race came from his pitlane start when he made places on the first lap, passing the ailing Oscar Piastri plus Daniel Ricciardo and team-mate Kevin Magnussen as drivers were caught behind the slowing McLaren at the bottom of Eau Rouge.
“I passed Danny after the top of Eau Rouge,” he said. “I mean, there was a massive pile up at the bottom of Eau Rouge.
“They all had to lift and give way to each other not to crash and I just came down closing the gap full gas, and that was pretty funny.”