Five new World Records, including the absolute World Record for closed circuits, fell to the experimental Mercedes-Benz CIII Mark IV during testing of a new aerodynamic shape at Nardi) in Southern Italy on May 5th. The new records stand to Dr. Hans Liebold, head of the car pre-testing department at Daimler-Benz, Stuttgart. He raised the closed circuit record to 403.9 k.p.h., easily breaking the previous record of 355.9 k.p.h. Set in 1975 by Mark Donohue with a Can-Am Porsche 917 on the Talladega circuit, Alabama.
For this exercise the CIII dispensed with its record-breaking turbocharged five-cylinder diesel engine in favour of a twin-turbocharged V8 petrol engine developing 500 b.h.p. at 6,200 r.p.m. The tests were primarily intended to study the effects of aerodynamic design features and spoilers at speeds of more than 400 k.p.h. (248 m.p.h.). Also being studied was the effect of lightweight construction and tyres with a low rolling resistance (Michelins).
The other four World Records, all in the FIA listings, whilst the closed circuit record is not, are (previous records in brackets):
320.615 k.p.h. over 10 km. (283.101 k.p.h.)
335.454 k.p.h. over 10 Miles (282.673 k.p.h.)
375.670 k.p.h. over 100 km. (316.484 k.p.h.)
367.396 k.p.h. over 100 miles (319.835 k.p.h.)