In 1985, the upper limit for engine displacement in the GTU class was raised to 3,000 cc, and Nissan, Toyota and Pontiac all decided to enter the fray. The Pontiac Fiero took the most wins in the season, six in total, including three in a row. However, even this was not enough to prevent Jack Baldwin winning his second championship in as many years to give Mazda its sixth consecutive manufacturer's title.
  On top of this, the 13th round Road America 500 Mile race saw the RX-7 win its 67th IMSA victory to knock the Porsche Carrera out of the record books for most wins by a single model.