For the 1995 World Rally Championship season, the FIA ushered in a new regulation stating that cars competing in its top-tier Group A category could not exceed 300 BHP in the interests of safety. 

The WRC’s four competing manufacturers - Toyota, Subaru, Mitsubishi, and Ford - complied by fitting their cars with restrictor plates that blocked excess air from passing through into the turbocharger, and giving them a power advantage. 

Sort of. 

Despite having taken the drivers’ and manufacturers’ championships in 1994, Toyota came into ’95 on the backfoot as its new car, the Celica GT-Four ST205, was too big compared to the nimble Subaru Impreza 555 and Mitsubishi’s emergent Lancer Evo. Even worse news for Toyota was the fact the newly-introduced restrictor plates hobbled the power advantage it had enjoyed previous year.

To circumnavigate the ST205’s shortcomings, Toyota Team Europe - or ‘TTE’ - who ran the Japanese carmaker’s rally programme came up with a solution. 

Cheating. 

The car was fitted with a small, spring-loaded device, which slightly retracted its restrictor plate while the engine was running. This allowed more air into the turbocharger than the rules permitted, and gave Toyota’s drivers - reigning champion Didier Auriol, four-time WRC title winner Juha Kankkunen, and part-timer Armin Schwarz - an extra 50 BHP. 

With the engine idling, the spring device retracted, meaning the restrictor plate returned to where it should have been were it legal. The quality of the component was so good, that it took the FIA until the seventh and penultimate round of the season in Catalunya to find Toyota out. 

As to how Toyota got found out, that remains one of the WRC’s biggest mysteries. TTE was immediately banned from the championship, while its drivers were stripped of their points for having an illegal car.

At the time of Toyota’s ban, Auriol and Kankkunen were largely out the running for the driver’s title, but the manufacturer’s crown was still to play for. Ironically, all Toyota could muster in ’95 was a single victory. 

Despite massively breaking the rules, Toyota’s illegal restrictor plate went on to be described by FIA President, Max Mosley as “beautifully made” and “the most ingenious thing I have seen in 30 years of motorsport.”

Text: George East / Photos courtesy of the Girardo & Co. Archive