wing comments, rear wing Options

[Glenn832]

This is just a fantastic forum! Being quite the newb, forgive me if I'm on the wrong thread. I need some advise and I know that it'll be freely if not copiously given. I like it already!

We've got a '74 that, at the moment, is in pieces. It's a street/track (little more focus on the track) baby that is getting some minor additions to help with high speed stability. One is the addition of a rear wing. There are two choices. As you can see from the pics, it's not pretty but at this point that's not the point.

What do you think about aerodynamics/functionality and also aesthetics?

[Joe Ricard]

My car is 5 MPH faster with wing and air dam than without and a heck of a lot more stable. Also bumped MPG so it's really not a fluke. Real air foils don't need a huge angle of attack to be effective.

Yes this very same wing mounted on a civic hatch with 10 degrees of angle slowed his car down 7 MPH.

I run my wing about 2 or 3 degrees high speed 100 + and crank it up high for Autocross. It has lees effect under 60 MPH.

[Glenn832]

My car is 5 MPH faster with wing and air dam than without and a heck of a lot more stable. Also bumped MPG so it's really not a fluke. Real air foils don't need a huge angle of attack to be effective.

Yes this very same wing mounted on a civic hatch with 10 degrees of angle slowed his car down 7 MPH.

I run my wing about 2 or 3 degrees high speed 100 + and crank it up high for Autocross. It has lees effect under 60 MPH.

For byndbad914 and joe, question:

What distance are you running your front dam/splitter off the ground for maximum effect? And how long/wide does a splitter have to be to effectively prevent air from "rolling" under the air dam?

We're in the midst of constructing a dam for the street with adequate clearance and then have an extension that would be even lower that would have the splitter attached to that to give us the required ground effects.

[byndbad914]

What distance are you running your front dam/splitter off the ground for maximum effect? And how long/wide does a splitter have to be to effectively prevent air from "rolling" under the air dam?

We're in the midst of constructing a dam for the street with adequate clearance and then have an extension that would be even lower that would have the splitter attached to that to give us the required ground effects.

Splitters tend to work more with how far they stick out v. how low they are to the ground - they do as implied and split the air. So that said, the longer you can make the splitter stick out of the front of the car, the more downforce you get because air attempting to bend down under the bumper and travel along the air dam is forced to stay above the splitter and therefore that creates downforce. I would put an air dam and splitter as absolutely close to the ground as possible. I heard a rumor in NASCAR that the splitters on the COTs are needing to be changed out regularly because the guys were basically dragging them on the ground.

So to recommend a splitter length is a bit hard as really you want it adjustable (able to be slid out further when necessary) but I would say have it stick forward at least 2-3" in front of the dam.

My splitter height is frankly set by the dam the nose had built in and the suspension travel I needed for the local 4x4 track they like to call a road race course (IMG:style_emoticons/default/smile.gif) I was much lower on overall height in CA for Willow Springs...

As for the comment about vortex generators and how they separate flow, that is a specific type of vgen similar to what you see across the rear roof line of a Mitsu or out on the wing of a jet the next time you fly.

Go to the paddock and search out the thread race914 had started about vgens being used on large trailers with flat backs. I am still a bit skeptical (you will see my posts) but he ended up going to ButtonWillow and seeing an increase in speed and some effect from his rear spoiler finally. I plan to put them across my rear deck and lower the wing some more to increase overall stability. The idea is those supposedly bend the air down, but I have to wonder if they kick the air up first, then it bends back down not much more than where it was to begin with...

But they may also decrease drag at the rear section of the car by flowing better behind the car where it meets with the under air again.

edit - oh, and to agree with Joe's comment on wing angle, I was essentially "flat" across the top of the wing which is about a 3-4deg chord angle at Willow Springs (really high speed track) and you can see in my pics, I run much more angle (last time I tried 12deg and that is what you see in the pics) trying to use it more as a spoiler than wing, since the track is much slower. But I also slowed down a couple mph in the front stretch (I hit between 130-135mph at Pueblo but was 150+ at Willow on the front stretch). Before the wing and splitter I was ALL OVER the front stretch at Willow around 135-140mph and the car is much more stable now.