I am going to start at 10* and move up from there. I made it adjustable.

 

I finally ended up buying a Ciro Design Wing about 6 weeks ago after selling off my Kognition a couple years ago. I haven't done much testing thus far, but my first event led me to make a fairly significant rear toe change, as the car was much pushier with the wing that without. I was running a 6" splitter made out of 15/32" plywood mated with the OEM Evo 9 front bumper. First mistake: The splitter was about 1-1/2" too low and proceeded to splinter apart by our last runs. One thing to note is that once the splitter lost all its integrity, the front has noticeably less grip and began to wash out. I, for one, did not think that a simple splitter would provide that much benefit at autox speeds.



Our second event with the wing and splitter was Solo Nationals (I know, great time to make such a significant change). Running on the practice course led us to lower the angle of attack of the top element by one notch (40* AOA). Based on the CFD analysis I've seen, that's still ~325lb of downforce at 80mph. I also built a new 6" splitter that had much more rigid mounting than the last, and was about 2" higher. I didn't however, add any support rods. From pictures, it looks like there was a little sag at the leading edge when the car was at speed. The result was less push, but the car still doesn't rotate like it did prior to the addition of aero. Note, I haven't yet changed spring rates.



I still think the rear aero is greatly overpowering the front. I've picked up a Voltex street front bumper and plan on building a new splitter w/ venturis and the like to try and create a bit more downforce at the front, sort of like Evolutionary's splitter setup. I will also be experimenting with spring rates as well.

 

The splitter is deflecting a fair amounnt. Looks like it might be doing something afterall.

 

Thanks for confirming my thoughts... I added an Aeromotions rear wing, and the balance is off causing front end push/under-steer. I've though about reducing the AOA in the rear for balance purposes until I get a proper front splitter setup.

 

Suspension setup (spring rates, alignment, etc.) before aero /= after aero. You should be looking at more than just a front splitter to rebalance the car. Make the splitter to the limit of the SM rules, then go back to suspension.

The fun of aero is that you can make a really loose car for good rotation at low speed (get around those tight turns) and then have it balanced or understeer at high speed for confident stability on high speed elements. For autox, that range covers 30-75mph. For road course work it is much higher.

 

Is that the Voltex replica bumper? Ask Balrok about his experiences with that at Road Atlanta. I'm sure autox speeds it should be good, but at +100mph the lower portion separated from the bumper section. And upgraded Alumalite splitter has done the trick.

 

This one is actually all one piece, so I shouldn't have that issue. I'm planning on adding an alumalite splitter as well.

Aaron, suspension changes are already on the list for the off-season. As well as playing with some wheel/tire setup ideas.

 

Is this a replica or the actual part? Would you mind sharing where you bought it?

 

Ya it looks like the same as mine but this one is a "Street" where as mine was the "Cyber" lookalike so it had that POS undertray. I think I can build and destroy 25 of these for what you'd pay for a real cyber bumper.

 

Is the overall width of the Voltex bumper the same as the stock bumper when viewed from above? I ask because SCCA allows you to replace front bumper but then limits your splitter width to the widest part of your front bodywork/fascia. Or do fenders count and they're wider than everything?

 

For reference:

The splitter and the canards can be as wide as the widest part of the bumper. Fenders are not included. To me, the widest part of the bumper is anything that is permanently attached/molded into the bumper. Add on bottom lips that get wider would be more like a splitter or air damn. In the case of the bumper Rich has posted, the flare at the bottom is molded in, so I would think his canards and splitter can go to the width of that feature.

 

^ non oem bumper use same rules?

 

Yes. Street Mod allows changing the front bumper. If one wanted a 10' wide splitter, they could get a custom 10' wide front bumper and it would be legal. Just make it strong enough to support hitting cones at 70mph. Probably 4-5 at a time

 

In essence that was my original question; thanks for your insight. Obviously you don't want to get too wide on the front bumper but I was curious to SCCA's interpretation of whether you were limited to original width or aftermarket bumper width.

 

Finally got my wing after an amazing 12 week wait. Now looking to make sure I have enought structure and bracing to prevent the wing from causing issues with my trunk.

Does any one have any info or pics of trunk bracing for a trunk mounted wing?