Audi has swapped chassis for the second and final day of testing at The Prologue, after battling issues with its new-generation diesel-powered prototype on Friday at Paul Ricard.

The No. 7 Audi R18 of Andre Lotterer, Benoit Treluyer and Marcel Fassler fought a series of undisclosed mechanical issues, losing three hours of track time in the afternoon and only completing four laps in the night session after a spin by Lotterer.

In total, the Audi completed only 106 laps on Friday, compared to 227 laps from by the No. 2 Porsche 919 Hybrid, which set the pace in all three sessions in the opening day of official testing.

An Audi spokesperson told Sportscar365 that the freshly built No. 8 car has been re-numbed to No. 7 for the final day of the test, and will be run in order to “prevent further damage to the [No. 7 car] chassis.”

Lotterer, Fassler and Treluyer will continue to handle testing duties today, with teammates Oliver Jarvis, Lucas Di Grassi and Loic Duval set to use the same chassis on Sunday and Monday.

A number of teams, including the German squad, are staying on at Paul Ricard for additional testing.