Toyota lifts lid on near “impossible” mission to upgrade its WRC car

Toyota had to pull “some favours and tricks” to complete the almost “impossible” job of upgrading its World Rally Championship car following a late change in regulations for 2025.

The reigning WRC manufacturers’ champion successfully debuted updates to its GR Yaris, which required spending three homologation jokers in the 2025 Monte Carlo season-opener last week.

A late change in the regulations last year to move away from hybrid power and reduce the air restrictor to 35mm for 2025 forced Toyota to take action and deviate from its intended 2025 development plan for its car.

According to technical director Tom Fowler, the team had six to eight weeks to complete its upgrades in time for Monte Carlo but managed to pull off the feat thanks to a “big collaboration” between departments and suppliers.

In that period, Toyota was able to upgrade its engine, camshafts, exhaust manifold and produce new gear ratios having originally intended to upgrade its differential – a development that has been frozen following the loss of hybrid power.

“The important thing from the team is that we found out with a maximum of six to eight weeks remaining that development had to change and we managed to do new camshafts, new exhaust manifold and five gear ratios in that time,” Fowler told selected media including Autosport.

“It was a big collaboration between engine department, transmission department and supplier to make that happen.

“If you write down the time it takes to make those gears, make those manifold parts and to grind camshafts, if you use all the standard delivery times it is impossible, so we really had to pull some favours and tricks to get that done. It is testament to our engineers and our designers that it happened.

“If you have a smaller restrictor then your engine characteristics change mostly around the rev range, so it becomes more important to use the rpm lower than before which affects the tuning of the engine, so the engine jokers were changed at the last minute.

“We always have a new engine for Monte Carlo and we changed the development plan in October and November last year when the restrictor size was coming as news.

“We did some camshafts and an exhaust manifold which are tuned specifically for the new intake size. So that’s two jokers on the engine for those parts.

“Then at the same time, we used a chassis joker to change the gear ratios in the gearbox and again that was a last-minute change as we are not planning to do that.”

All of the upgrades were fitted to three of the five GR Yaris in Monte Carlo with Takamoto Katsuta and Sami Pajari set to receive the full 2025 package at a later date.

It proved to be a successful debut for the team as Sebastian Ogier and Elfyn Evans headed a one-two with Kalle Rovanpera finishing fourth.

Watch: Rallye Monte-Carlo Wolf Power Stage highlights