For most of the test we used a 4″ splitter on the airdam. I wanted to see what removing the splitter extension would do. We expected a loss in downforce, but I wasn’t sure if drag would go up or down. You see it both ways online, with CFD data showing that a splitter reduces drag, and the occasional internet expert claiming that drag goes up.
| Splitters | Front Cl | Rear Cl | Total Cl | Cd | L/D % | HP @ 100mph |
| VGs, splitter, wing | -0.20 | -0.61 | -0.82 | 0.52 | 1.57 | 57.58 |
| VGs, no splitter, wing | 0.18 | -0.64 | -0.47 | 0.53 | 0.88 | 58.75 |
Score one for the CFD team, the splitter reduced drag slightly. When I removed it, the drag went up from .52. To .53. More importantly, we lost a lot of front-end downforce. Our raw data showed a loss of 69 lbs on the back straight, which calculated to a .38 delta in front coefficient of lift. Let’s see what that’s like in OptimumLap.
| Splitters | Watkins Glen | Waterford Hills | 2010 SCCA Nationals |
| VGs, splitter, wing | 2:24.32 | 1:20.42 | 1:03.54 |
| VGs, no splitter, wing | 2:25.65 | 1:21.12 | 1:03.89 |
Obviously, if you’re running just an airdam, and the rules allow it, add the splitter. It’s significant.
Occam's Racer 