PORSCHE RACING HISTORYKees Nierop (CDN)
1985 : Road Atlanta 500 km - 2nd in class : Road America 500 Miles - 2nd in class
3 February 1985 - Daytona 24 Hours - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 7 | Porsche 935/84 | 935/84 | GTP | Jim Mullen (USA)/Kees Nierop (CDN)/Ray McIntyre (USA) | Obermaier Racing (D) | 5th | 5th | 20th | 668 laps |
14 April 1985 - Road Atlanta 500 km - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 91 | Porsche 934 | 930 890 0014 | GTO | Chester Vincentz (USA)/Kees Nierop (CDN) | Electrodyne Performance (USA) | 12th | 2nd | 23rd | 111 laps |
25 August 1985 - Road America 500 Miles - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 91 | Porsche 934 | 009 00030 | GTO | Chester Vincentz (USA)/Kees Nierop (CDN) | Electrodyne Performance | 12th | 2nd | 23rd | 110 laps |
8 September 1985 - Pocono 500 km - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 91 | Porsche 934 | 009 00030 | GTO | Chester Vincentz (USA)/Kees Nierop (CDN) | Electrodyne Performance | 26th | 9th | 15th | 92 laps |
29 September 1985 - Watkins Glen 500 km - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 91 | Porsche 934 | 009 00030 | GTO | Chester Vincentz (USA)/Kees Nierop (CDN) | Electrodyne Performance | 14th | 4th | 27th | 81 laps |