Honda tested an upgraded power unit during practice for the Azerbaijan Grand Prix on Friday, with the new unit delivering a substantial performance boost.
The McLaren engine supplier was due to deliver the upgrade for the Canadian Grand Prix a fortnight ago, however they chose to delay it whilst they ran further dyno checks to both prove its reliability and performance gains.
The unit, dubbed 'Spec 3', was fitted to Fernando Alonso's car for both FP1 and FP2 and data showed a top speed of 327km/h for the Spaniard, compared to 312km/h for team-mate Stoffel Vandoorne, with the Belgian running the old spec.
That means a gain of 15km/h, however that still remains some way off the top speed of the day – 354km/h – posted by Force India's Esteban Ocon.
Honda's motorsport boss Yusuke Hasegawa said the data proved the upgrade had delivered what was expected of it.
"We came to Baku armed with an update for Fernando's PU, which we ran during both practice sessions today," said Hasegawa.
"Working through our programme in accordance with today's schedule, I can confirm that we were able to see the effectiveness of the update in the data."
Alonso – who retired from FP2 with a gearbox failure – isn't due to run the upgrade for the remainder of the weekend however, with Honda keen to study the data collected on Friday before a likely debut at the Austrian GP in a fortnight, which is likely to include further updates to the hybrid system.
Speaking on Friday, McLaren's Eric Boullier said Honda "have a plan" in place to bridge the gap to their rivals and McLaren must wait and "respect" Honda's promises.
