PORSCHE RACING HISTORYChester Vincentz (USA)
1985 : Road Atlanta 500 km - 2nd in class : Road America 500 Miles - 2nd in class
24 February 1985 - Miami IMSA GTO - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 91 | Porsche 934 | 930 890 0014 | GTO | Chester Vincentz (USA) | Electrodyne (USA) | 18th | 18th | 6th | 27 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 |
5 October 1985 - Columbus IMSA GT - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 91 | Porsche 934 | 009 00030 | GTO | Chester Vincentz (USA) | Electrodyne Performance | 4th | 4th | 8th | 36 laps |
1 December 1985 - Daytona Finale 3 Hours - IMSA - International Motor Sport Association
| No. | Car | # | Class | Drivers | Entrant | Pos | Class | Grid | Notes |
| 91 | Porsche 934 | 009 00030 | GTO | Chester Vincentz (USA) | Electrodyne Performance | 66th | 22nd | 33rd | 19 laps - DNF |