The UNSW Solar Racing Team has completed its World Solar Challenge campaign with an impressive result, finishing fourth in its class and winning the CSIRO's award for the most energy efficient vehicle.

Jaycar Sunswift III, the UNSW solar racer, crossed the finish line of the 3000km race in Adelaide on Friday, October 26, after setting out from Darwin on Sunday, October 2.

The car placed fourth in its division of Adventure Class and was 11th overall in a race won by the Dutch Nuon team.

However it was the unexpected CSIRO Technical Innovation Award for the most energy efficient vehicle which gave the Sunswift crew their biggest thrill.

"It was because our car was the most efficient in the entire race, which is fantastic because that's the point of the entire event," team leader Yael Augarten said.

Jaycar Sunswift III underwent some extensive redesigning following its world record-breaking crossing of Australia from Perth to Sydney at the start of this year.

Team member Mark Smith, an engineering student who designed and built an entirely new suspension system for the car before the World Solar Challenge, said the car had performed flawlessly and reached speeds of up to 100km/h.

"It was really good to get to Adelaide without so much as a bolt needing tightening and the handling was brilliant," he said.

"I would almost call it relaxing at 90km/h. Anything like a road train coming towards you at 100km/h and you hardly even noticed the buffetting."

The Adventure Class of the World Solar Challenge is for vehicles which have qualified to compete in previous events but do not meet the current year's design requirements. The lead Challenge Class is for newly built vehicles which meet all current design requirements - which this year included an upright seating position, headlights and reverse gear.

Jaycar Sunswift III was the first silicon cell vehicle to finish in Adventure Class - other vehicles use more advanced and expensive materials for their solar cells.

Sunswift was also the first two-seater vehicle - although it only has one driver on board, the car carries ballast to make the weight of two people.