The Australian distributor of eight car-care brands, including Meguiar's and Liqui-Moly has renewed its support for the street car festival from next year.

Summernats co-owner Andy Lopez would not disclose the value of the sponsorship but said he was thrilled. ''MotorActive … have helped define how the Summernats has grown over the past 20 years, and their commitment to both the event and the wider street machine community is a shining example to other automotive companies,'' he said.

Managing director of MotorActive Bruce Morrison said the sponsorship was a great fit.

''When we commit as a company to something like the Summernats, we don't take it lightly,'' he said. ''I have personally never missed a day of the event in the past 20 years that we have been involved. When we first came to Summernats it was just me and my brother Ray, and we just had a small tent with a car on display.''

MotorActive took the naming rights sponsorship of the National Burnout Masters under the Liqui-Moly brand three years ago and Mr Morrison said it made burnouts safer.

''With the Liqui-Moly National Burnout Masters, we worked hard with the new Summernats owners to really legitimise burnouts as a form of professional motor sport and clean up their image.''

Saturday's smoking Burnout Championships eliminations and National Burnout Masters eliminations were watched by thousands of car enthusiasts, who were blanketed in thick black smoke as tyres popped and shredded.

The lines for frozen drinks were 20 deep as revheads tried to keep cool, and one hat seller sold out of sombreros. But as the mercury peaked at 40.1 degrees and some revellers hydrated with alcohol rather than water, 32 people had to be treated by paramedics for heat stroke.

The director of clinical operations for Ambulance Service Australia, Michael Rigo, said he was impressed at how sensible and sun-safe the crowd was.

''This is a very low number of heat-related incidents for an event of this size. We have a team of intensive-care paramedics and a doctor on site to treat those in need, but so far, this year's Summernats has been a walk in the park.''

But from one extreme to the other, Summernats was then belted with rain when a freak thunderstorm blew through Canberra at 6pm, dropping the temperature by almost 20 degrees in three hours.