Update 4/7/17

Some people were having problems with the bracket to frame attachment bolts breaking. I wasn’t, but some were. I think the real problem was that they were “upgrading” to a grade 8 bolt. This is a high vibration application, and the bolt is in single shear. IMO, this is not the place for a grade 8 bolt. According to Carroll Smith, “There is no place on a race car for a grade 8 bolt.” While I don’t agree with that statement 100%, as a general rule, I think that is true.

In any case, Exomotive sent me an upgrade kit for free. Well, almost for free. I paid a couple of bux for shipping. The kit consisted of a drill bit (which was bent and I tossed), a good tap, and some upgraded fasteners. The whole job took me about an hour.

During the original assembly, I upgraded to these allen bolts on the left. Allen bolts are stronger than cap screws. The new bolts are on the right.

This is the final assembly. Certainly looks stronger? We’ll see. Now, if one of these breaks, I’m gonna be kinda unhappy. 😉

Does the car need a rear wing? Absolutely! It needs a LOT of rear wing. With out it, there almost no weight back there, and you just can’t get any traction. Doesn’t seem to need anything in the front, though. Not yet, anyway.

Original Installation

The car (apparently) needs a rear wing for down force. I have been told by Exomotive and other racers that there is no need for a front wing. There’s enough weight on the front, and enough down force from the hood that it only creates drag and doesn’t improve lap times. We’ll see about that.

When I ordered the kit, I ordered the CoT wing mounts, both front and rear. Not such a good idea. The supply of CoT wings has pretty much dried up. I have this dual plane wing that I’v had for a while, so I’ll use it for now.

Exomotive sells a really nice carbon fiber APR GTC-200 single plane wing that’s said to be very efficient. But at $1,100, I’ll hold off on that for now. At some point, I’ll probably break down and order one. Hey it’s carbon fiber and looks cool! It must make the car faster. Especially if I put some stickers on it. 🙂

So, this is the original installation. The CoT wing mounts are slightly different than the APR mounts. They put the wing up into the air a little more, and further back on the car. And, ideally, that’s where you want the wing – up into clean air as much as possible. It might even be a good idea to mount it directly to the rear roll bar.

With the wing that high, it won’t fit in to my trailer! That’s not going to work. I could just take the wing off and on for trailer loading. But that’s a PITA. And sometimes bad weather will roll in quickly while I’m out on the track. It’s a good idea to be able to come off the track and drive right on to the trailer. I could just buy a new trailer. But I already own this one, and I like it a lot. Serpent Express Trailer

The first step is to shorten the CoT mounts. Pretty easy. A couple of minutes with a Sawz-All. Then drill a couple of holes for the front mounts. I drilled the top ones first. Then decided I didn’t like that, and drilled the bottom ones.

Then it’s a fairly simple matter of bolting the wing in place, with the proper struts. I made the struts out of some 5/8″ alum rod and some 5/16″ rod ends. I didn’t have any left hand rod ends, or a left handed tap. So you have to unbolt it to make an adjustment. Not a big deal really. The struts only get adjusted once. To fine tune the down force, I’ll make adjustments to the top wing.

I haven’t tried it yet. But this should easily fit in my trailer.

I set the main wing to 0.5* of down angle. Ideally, it should be zero for good down force with minimal drag. But the AOA will change as the car moves down the track, and I don’t want to get any lift. The upper wing is about in the middle of it’s range as a starting point. I’ll use tire temps to adjust the angle. That’s a good theory, isn’t it? 🙂

4/2022

I did some upgrades here. Last year I switched to a big Wang. I didn’t feel that the AR wing was doing anything good. Not a good balance between downforce and drag. Last season I adjusted the Wang down to about 6*. It gave me more downforce, but not enough at the lower speeds. It was still too easy to spin the rear tires and develop oversteer.

I was thinking that with the wing sitting below the cage, it just wasn’t getting enough clean air for it to be really effective. But, if I raised it up above the cage, it wouldn’t fit in the trailer. Time to invent something new. I needed a wing mount that would quickly and easily fold down to fit in the trailer. But also be strong enough to handle the rigors of racing.

This is what I started with in January, 2022.

I used this small lathe that I bought from HF a while back. Not incredibly accurate. But good enough for this job.

I also used this tubing notcher I bought from Eastwood sometime in the last century.

I used 5/16″ rod ends anywhere it might need to pivot or move. The end with the black stripes on it is a left hand thread.

It fits perfectly. You can see the long diagonal bar that is unpainted. That is a piece of steel tubing I had lying around. It really makes the whole thing incredibly stable. No lateral movement at all.

I welded a tab on to the bottom of the original Wang bracket to connect the cross bar.

Using a 1/2″ socket and a 1/2″ end wrench, I can remove three bolts, and then it folds forward.

I put some split rubber tubing on the bracket to protect the leading edge during transport.

How does it work? Great! I set the Wang at 3*. A good place to start, I think. We went to La Junta Raceway last weekend. It was a huge improvement. I mean…. Huge!

I was able to get on the gas so much sooner. It never spun the rear tires. A couple of times, I even managed to get a little understeer. The car has never done that before.

A fast lap around La Junta Raceway, La Junta, CO.

I’m not really sure what was happening here. But it made me laugh. 🙂