Honda technical director Toyoharu Tanabe has said the engine manufacturer “need to be careful” as they prepare to introduce an upgrade in Canada.

The Honda power unit has become renowned for its lack of performance and reliability over recent years but have got their new relationship with Toro Rosso off to a stable start.

The next step in the engine plan is set to be rolled out in Canada, but Tanabe says the predominant aim is to keep searching for the perfect balance between power and reliability.

“So far it [reliability] looks stable but I think we need to be careful not push too hard on the performance. We need balance,” Tanabe told Motorsport.com.

“We have a lot of things to do and not many short-term solutions, most are long-term. [If] we develop something and then apply it to the engine, we need to have a reliability test.

“Any tiny thing to improve the performance, we need time.”

Toro Rosso driver Pierre Gasly is looking forward to seeing what Honda have to offer.

“I’ll wait until FP1 to see exactly what the difference is on the computer,” said Gasly.

“I’ve learned that in Formula 1 it’s better to wait and see once you put the new parts on because sometimes it doesn’t work as well as you expect, sometimes it works better.

“But it can only go in the right direction, I think, so I’m really excited about this upgrade.”

Red Bull are set to closely compare Honda’s performance with Renault in Canada as they prepare to make a decision on their engine partner for next season and beyond.