Any car using LPG fuel in the 2010 Dunlop MSA British Touring Car Championship will have to run with a smaller 37mm turbo inlet restrictor on its engine from the series' next round at Oulton Park onwards, it has been announced today.

BTCC organiser TOCA has taken the decision to reduce the restrictor size after carefully monitoring - with the use of exclusive data - the performance of the Team Aon Ford Focuses in the season's opening nine races.

Team Aon has become the championship's first front-running team to experiment with liquefied petroleum gas. At Brands Hatch earlier this month its drivers Tom Chilton and Tom Onslow-Cole each took a race win - the first-ever for LPG power in the BTCC.

"The LPG engine is very much 'work in progress' for both Team Aon and the championship, which is why we have a specific regulation that allows us to make changes along the way - and it may not even be the last time we make some relatively minor tweaks to the specification, either up or down," explained BTCC Series director, Alan Gow. "Likewise with the new TOCA-NGTC turbo engine; there may be a time when we will also need to fine-tune its characteristics during the season.

"However, let me be absolutely clear; the decision on the LPG engine was made after logging and carefully analysing data from all its first nine races, then comparing that same data with those from other top cars - it was certainly not as a result of any team or driver complaining. Anyone who knows me will know very well that 'whinging' has absolutely zero effect on my decisions.

"It's worth remembering that, as all cars are fitted with our mandatory data-logger, only TOCA has the ability to fully download, compare and analyse the exact same performance data from every car and at any time. This is how we are able to carry out comprehensive performance evaluations, produce factual comparisons and to then make a sound decision based on quantifiable data.

"Therefore anyone who may moan or theorise about the relative performances of different cars is generally using little more than self-serving guesswork, often laced with a fair amount of paranoia. But, thankfully, we don't run the championship in that same way."