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.