Re: BlueScooby's 06 STI - Looking around at rear wing options
That's just my $0.02
Yeah even the least downforce producing APR wing puts something like 8 batteries worth of downforce on the back of the car at typical strait-away speeds....Just imagine taking the next turn with that without 8 batteries on the front as well. HELLO UNDERSTEER. However you can do what the FWD guys do and set the car up to be very loose/twitchy without a wing. What this does is make your car very agile in the slow speed stuff but the downforce of the wing brings the car back to a neutral state the faster you go. You can always adjust the angle of attack to raise or lower the speed at which the car becomes neutral.So I talked with Ryan at Zebulon a bit through email and I think I'm going to have to hold off on the spiltter/rear wing thing for now. They really do need to be done at the same time, and I'm just not ready to put on a GT wing...
Porsche found this out when Norbert Singer was developing the 962. It was the time when F1 had just found ground affects and they thought that it would translate onto a full bodied car. It didn't when they did it the way the F1 cars were doing it... i.e. skirts. Skirts actually made the car worse. They realized with full bodied cars you have to actually do it backwards compared to the theory behind skirts, you need that air coming in from the sides for the tunnels. Whence they fixed that the car made 2.5 times the down force compared to no ground affects at all. You only want to seal off the sides of the car via skirts or vortexes when you have a completely flat underbody and use the rake of the car as your pressure differential device. When you have a defuser or tunnels you want as much air going into them as possible to maximize their effect.But he also gave me a couple pointers on the underbody that I'm going to see if I can work with. He reminded me that the skirting is illegal for any sanctioned race (which I already knew) but also that the skirts sort of open/close off the underbody at various spots which is probably hurting me a little.
You would need to overhang the rear wing quite a bit for the wing to interact with the diffuser. If you cut it short and made the diffuser to bumper transition smooth the air flow won't want to detach as soon and keep moving up a bit before it separates completely and will give the negative pressure area under the wing a better chance of interacting with it better. Cause lets face it, unless your wing is massive and it over hangs the trunk the negative pressure area under it is not going to reach down far enough to interact with the air exiting a diffuser on our cars....the distance is just far too great. Look at Nemo's EVO, Scorch Racing's S15, Tilton Interior's EVO, Andy Forrest's Impreza, and the RP968 and you'll notice 3 things: The unbelievable size of their rear wings, the amount of overhang off the rear of the car they sit at, and the height of the tunnels under the car are measured in feet, not inches.Also that with the rear diffuser sticking out that far, its really limiting (preventing) the rear wing from aiding in drawing air out from under the car...
IMO I would just go with the S7-S8 wing if you keep it long or stick with the OEM wing if you shorten it. It's still a street car and sometimes the simplest way is the best way.SO, it sounds like I'm going to be revising it a bit. In general i think I'll feel much better about it after its no longer sticking out so far, but that also means I probably won't be able to deflect the exhaust up to prevent interference anymore...
I may still look into some of the rear wing options from above (possibly) since they shouldn't be a dramatic change in the airflow enough to change the car's balance.
That's just my $0.02