Honda to leave Canadian Grand Prix F1 engine upgrade decision late

It is the only one of the four manufacturers to have not yet spent any tokens during the season, leaving it with 18 still to spend.

Honda chief Yusuke Hasegawa said he was encouraged by dyno results back at the factory in Sakura.

But further testing is required before Honda will feel comfortable confirming the token spend with the FIA and introducing the update.

Honda had hoped to make a decision by the end of this week, but a call is now set to be made in the days just before the Montreal race weekend begins.

"There is no doubt that power is important for Canada," said Hasegawa.

"It's stop and go circuit, so fuel consumption is important.

"I want to introduce some of the updates of course, but at this moment, we can't confirm.

"The planned update in Sakura is on dyno, I saw some of the good results.

"The thing we have to do is confirm that the technology is OK."

The update is to be focused on the internal combustion engine.

Renault used three of its development tokens for its engine upgrade at last weekend's Monaco GP.

The French manufacturer believes the upgrade has delivered as much as 0.5 seconds in laptime, depending on the circuit.

Hasegawa confessed to being surprised by the level of Renault's improvement, particularly as so few tokens were used.

"Yes, I was surprised," he said. "Just the three tokens they have used.

"If the rumour that the update is they are changing the combustion [is correct], I don't think they can do it with just three tokens.

"I'm just judging by the rumours, I haven't seen the actual numbers."