Peter Turnbull started racing in 1964, competing in hillclimbs and motorkhanas with the North West Car Club and the Morris 850 Club before moving into circuit racing. Even before that step, he and Tony Hamilton had already begun building race cars, creating the first Turnham in what would become a long-running line spanning more than 50 years.

The name “Turnham” combined “Turn” from Turnbull and “Ham” from Hamilton, with the first cars built at Turnbull’s Bodyworks in Wynyard. The earliest was Tony’s Turnham Sports, followed by Peter’s own Turnham Ford Clubman. These home-built machines quickly proved competitive, with Peter finishing third at the Symmons Plains round of the 1974 Australian Sports Car Championship.

In 1976, Peter raced in New South Wales and showed strong pace in qualifying and heats of the NSW Tourist Trophy, though his main race ended early after being hit from behind. Across his career, he competed at 45 circuits around Australia, while also achieving consistent success in Tasmania with wins and placings at Baskerville and Symmons Plains between 1969 and 1984.

The Turnham cars themselves became a common sight, particularly in the early 1970s when as many as five could appear in a single race. While the first Turnham sports racer was driven by Tony Hamilton, later cars like the Turnham Climax GM6 and Turnham TS8 Turbo were raced exclusively by Peter and later by fellow Tasmanian Motorsport Hall of Fame inductee Geoff Jacobs.

Despite his growing reputation as a builder, Peter remained a competitor at heart. In the early 1980s he switched to off-road motorcycle racing and won the Tasmanian over-40 enduro championship in 1986. However, an industrial accident in 1990 that cost him an eye brought his racing career to a halt when his licence was cancelled by Motorsport Australia.

After moving to New South Wales in 1994, Peter continued competing in hillclimbs and regularity events, winning the Formula Vee category of the NSW Hillclimb Championship in 1998. The formation of the AASA in 2003 allowed him to regain a full racing licence for their events, with Motorsport Australia eventually reinstating his licence in 2010.

Over the decades, Peter built a wide range of sports cars, clubmans, and Formula Vees. Between 1966 and 1978 alone, he constructed three sports racers and three clubman cars, though these evolved into more than 20 different engine and body configurations and were known by 15 different names.

In 1995, a Turnham Clubman entered in Targa Tasmania by Victorian driver John King showed promise but failed to finish after a suspension failure on the final day. Later, one of the most successful creations was the Turnham Bandit, built in 2003 for Andrew Walker, which achieved strong results in New South Wales hillclimb competition, including class wins, records, and championship podium finishes.

The final Turnham, the Steel City Special, was completed in 2022 and raced by Peter in historic events. At the time of his induction, six Turnham cars were still actively competing across Australia.

Nine Turnham cars had passed through more than 40 different owners over the years, yet five had returned to the Turnbull family. Peter retained three cars, while his nephew Clinton held a Formula Vee and shared ownership of the Turnham Rotary with his son Alex.