Wednesday, March 26, 2014

Splitting Airs

Last winter I shifted my splitter forward 2 inches to try to get more front down force, but it seemed to have a very limited effect. This is probably because the main protrusion of that splitter is just in front of the radiator grille. The air flow in the radiator and up over the car is not very significantly restricted, and less so with the AC condenser removed. Thus, the increase in pressure over the splitter vs under is probably minimal there. The sides gained extension too, but the sloped, drag reducing front of the car is probably also fighting the build up of pressure as well.

Since I improved the wing over the winter, I expect to generate more downforce in the back. To make use of that added downforce I will need more front down force. Otherwise I will simply go back to the car plowing on the fast sweepers. To that end, I've ditched the CF splitter and cut myself a much larger plywood one, similar to that used by the other street modified cars in my area. Here are some pictures of the construction process....

Jack it up, prop the board underneath

Scribe a 5.75" offset from the fender (viewed from above). The rule is 6", but leave a bit for safety and interpretation etc.

Painting with Rustoleum to give it a little water resistance...

Initial attachment.  The sides still need trimming, they stick out a little bit too far.

View of bottom attachments. As always I am attaching to hard points, not the fiberglass clam

If air passes above and below an added aero dynamic aid it is considered a wing. Front mounted wings are disallowed in the super street modified class, so trim the ends and put a back plate in to turn it back into a splitter

Another view. It's hard to see because of the paint, but Aluminum angle is used to attach the backplate

The final result from the front

The edges ere a bit floppy and I didn't want to attach to the fiberglass, so I rigged a turnbuckle system attached to the oil-cooler mounting point which is steel.

A slit in the fender liner is required. Re-installation is quite a trick since the top part of the fender liner is actually supposed to slip in first, but that is no longer possible. Really glad that i was conservative on the size of the back plates.

Ever so conveniently the vent for the oil cooler accommodates the turnbuckle! 

The result is that the turnbuckle system is not 100% rigid, so I may need to re-work this if the edges wind up flapping, but it should also work to dissipate and absorb some of the energy from cone impacts. The great thing about this is it was really really easy to install and provides a bit of adjustability if the corners turn out to be pulled upward by the tension (which is not legal if it's more than 3 degrees from level)

1 comment:

Gus Heck said...

It's worth noting that I have since eschewed the plywood uprights, as a misplaced cone can push it back into the tire, at which point there's significant risk that fasteners will wind up in your tire. Now I just use black duct tape.