My splitter stays were attached to the bumper impact beam via eyebolts into rivnuts, per an earlier image. I considered the combination acceptable, but only just, so at V3 I have replaced the rivnuts with welded in bushings and the rivnuts with stainless steel straps.
I have also added an additional pair of outboard stays, to better support the outer ends of the splitter. A thin nylon washer is installed between the straps and the bumper cover, so that the straps don’t wear through the cover.
The stay cables are fabricated from 1/16” 7x 7 stainless “aircraft” cable with a PVC coating. The ends are finished using Nicopress sleeves and AN100 thimbles. The inner and middle cables are almost the same overall length, differing only by 0.05”, so I have colour coded the middles to differentiate them. The outboard cables are much longer so easily differentiated from the others, but build tolerances in the splitter result in the ideal length of the two outer cables being different LH and RH by 0.09”, so these two cables are also colour coded (port side red) to avoid head-scratching down the road.
The cables connect top and bottom using AN115 shackles, with clevis pins . The upper clevis pins are secured with cotter pins and the lower ones with cowl latch safety pins. The safety pins are new at V3 and they really make life easier when removing and installing the splitter.
My car was built with headlight washers, which don’t really provide any useful function for a track car. As the bumper cover comes off with some regularity, I have left the washer covers off for a while now. I would prefer to seal up the holes to avoid errant airflow, so I decided to remove the washers entirely. All washer functions are on a single fuse (48, behind the glovebox), so disabling the headlight washer by pulling the fuse would also disable the windshield washer. Instead, I removed the headlight washer pump and all the associated plumbing, and fabricated a nylon plug to seal up the pump grommet.
The splitter diffusers have been revised at V3, with a curved ramp. I have no idea how far up the ramp the flow will remain attached, but I will check this out with flow vis when I get the car moving. Here is the V2 diffuser:
Here is the V3 diffuser:
The splitter diffusers attach into helicoils in the plastic splitter, to minimize the chance of stripping the threaded holes and to eliminate the bother of hex nuts. As a general philosophy, lap joints are completely avoided in the undertray, so the splitter has been rabbeted to allow the diffusers to remain flush.
Previously I relied on the existing undertray (installed above the splitter) to manage cooling air flow, but these are now removed. The splitter aft attach bracket has been replaced by a new one that provides the desired ground clearance, and that also now extends the full width of the undertray. This serves to seal the passage under the front subframe. I want to make sure that any air that moves past the engine and transmission actually does some cooling, rather than bypassing underneath the subframe.
I have fitted silicone baffles to seal the wheel well liners to the splitter diffusers. These allow the splitter to move upward in response to ground strikes, without applying shock loads to the liners.
Last year’s Delrin wear pads have almost worn down to the screw heads, so I will start this season with new ones. Although the part is a bit too pretty for its intended purpose, it adapts a part I have on hand from a completely unrelated product/project, so was the easiest solution for me.
That wraps up the splitter changes at V3.