Garry Grant (Alltrax), top and Bryan Hartley, engine builder with the 1964 Morris Mini Cooper S that the Nelson based Project 64 group hope will reach 250km/h at Speed Week at the Bonneville in the United States.

Garry Orton (left) and Mike Wilson with the trophy the team won for breaking a speed record in a Mini at the Bonneville Speed Week in the United States.

A little Nelson car with a British pedigree has spat the turtle out of its tank and clocked an unofficial speed record for its class on the hot desert flats of Bonneville, Utah.

The Project 64 team said today their 1964 Morris Mini Cooper S reached 223.2kmh on the salt flats, which is an unofficial land speed record for a 1000cc car. It will now need to repeat the feat to make it official, but things are looking up after the little car threw a minor wobbly after its first outing when it hit speeds of 210kmh.

The Project 64 team, which had worked the past year in a Nelson workshop to convert the Mini into a racy sportster, are happy with the car's outing at the annual Bonneville Speed Week.

SPEED HEAD: Nelson Hartley at Speed Week at Bonneville, Utah, in the United States.

Team member Chris Jones said a world land speed record was one of the goals the group had wanted to set.

"That's one of the things that has really impressed me with this group. They set a whole lot of goals before they set out and have worked to achieve them."

Team member Mike Wilson said the Mini had been "extremely well received" in a "crazy place full of a huge variety of people and vehicles". While it was a novelty it was in the company of a surprisingly large group of similarly small vehicles, such as three-cylinder Saab Sonnets and Honda 600s.

Mr Wilson said they were relieved to pass the technical inspection after being warned by the "old hands" it was a tough test. He said the easy pass was due to the incredible preparation that went into the car.

The Mini passed its first rookie run on Saturday, followed by a speed attempt when it "got off the line well" and disappeared into the distance. It peaked at a top speed of 210kmh, according to the onboard GPS, and recorded a timed run of 203kmh - the average over a mile.

Mr Wilson said it was during the last part of the run that something was not quite right with the car. The team initially thought it was the gearbox, but Mr Jones, from Nelson, today said it appeared to be a "bunch of other gremlins" linked to cooling the car in the hot desert.

"One of the things we're learning is how long everything can take out here on the salt, mostly because of the distances between things but also because of the extra complications of being so far from home," Mr Wilson said.

Team member Garry Orton said support from sponsors, including several Nelson businesses, had gone a long way towards completing the $100,000 project. The car sports a range of features to help it in its speed quest, including special tyres and a modified twin overhead cam engine which has been supercharged to propel the car's body shape at speeds well beyond what it was designed for. Mr Jones said the Mini, designed in the 1950s to combat massive hikes in fuel prices, remained unsurpassed in its volumetric efficiency. The small car has a ratio of 80 per cent passenger space to 20 per cent mechanical space.