i KNOW this has been discussed many times, but i can not, for the life of me, find a thread on where to have the wing sit on an Evo VIII/IX. i know i want clean air... i have a vortex generator, etc.
my wing has a 10" or 12" height available.

input on the correct height for placement? thanks in advance, guys.

 

depends on the profile/design f the wing.

2d - as much clean air as possible
3d - can be lower and still be very effective

whats the distance from trunk to roof line? my car is not near me.

 

Looks like going 3d, apparently....

Will measure in the morning.

 

Older but same info:

https://www.evolutionm.net/forums/mo...g-gt-wing.html

 

Oddly enough, I didn't see a word on the height. 12" seems to be pretty common.

 

 

Probably not best for my application.

 

dam...lol. Those things are huge....

 

Well height is relative to clean air, wither that's 12" up or 12 feet up, you can see the difference between say TA1's wing being way up and way back Vs some of the other applications like Vortex and Kog. So it really depends on the rest of your build and aero on true optimal placement. There's a CFD pic somewhere from the Mitsu people on the Vortex generator and that shows the area behind the windshield/trunk if that's something your after. K.I.S.S. if you ask me.

 

the pic is actually in that thread. air moves down and hits the OEM wing location at 9-11*.. .. but i will be running mine higher so my AOA will differ from OEM; again it's looking like a 12" height puts it in decently clean air. putting it higher, from what i can tell, won't help any. that is with the "standard" strut/wing placement most manufacturers are using.
THEN i have to figure out where the airfoil stalls. that should be fun.

 

Also consider rules for any classes you may want to compete in. For SCCA solo, I put my wing as far up and back as the rules allow. Top is 6" above roof line, back is even with furthest point of rear bumper.

For max AOA before stall, you should do tuft testing. Youtube it. Pretty easy and gets you strange looks when you have a bunch of strings on your car with a camera going down the road :-p I put my camera low on the back of the trunk to minimize air flow disruption, and pointed it up at the under side of the wing elements. Then adjust AOA and test. I used a digital level and referenced a spot on the trunk so I can set it when car is not level at events.

 

Luckily I have no class restrictions, so no worries there.
The foil I'm getting is designed to be a bit lower, in dirty air....so I guess that answers that question.

 

We could create a better graphic using our flow simulation software, but this gives an example of the airflow at the stock wing height. Determine the airfow angle at your wing height, as Aaron mentioned, then set you AoA for the desired DF, within the stall window.

 

that's not bad. but the OEM wing is only functional above 100mph, correct?

 

I've recently done some tuft testing with the stock wing. This is on an EVO IX with vortex generator at about 60 - 70 mph. You can see even from lower speeds the airfoil working. At the higher speeds there is nice streaming and upwards flow to the rear.