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For the few dozen of you who subscribe to the blog, let me update you on some of the things that have been happening in my life, and how that’s going to affect this site and future content.

I bought a Veloster N for what I thought were pretty good and mature reasons. I took the car to Watkins Glen for Grid Life, but I didn’t really get a chance to open it up in the monsoon conditions. An NC Miata would have been a better choice (if you don’t get that joke, it’s a boat reference).

Then I drove the VN out to Detroit to see my buddy Chris Gailey, and in preparation for that, I built a bunch of aero parts for testing. No plan survives the enemy, and my Veloster didn’t survive one lap.

I accelerated out of T2 at Waterford and heard a loud noise, which then got louder, kind of like an exhaust gasket getting blown out. I’d recently replaced the straight pipe with OEM, so I thought maybe this was a gasket issue. But then the car lost power, and then died as I entered the pits.

We took off the undertray and found oil; it didn’t look good. A warning came up on the screen, I touched that, and it called Hyundai service. They said they’d pick up the car and take it to the Hyundai dealership, Glassman Hyundai in Southfield.

While waiting for the tow truck driver to arrive (high as a kite), I let Chris’s son have my track day. The good folks at Summer Track Days allowed Griffin to drive in my place, and I let Griffin borrow my helmet. Unbeknownst to me, Griffin let his buddy borrow my helmet so he could ride shotgun. Welp, the passenger got sick, couldn’t get my helmet off in time, and threw up all over the inside of my lid. No good deed goes unpunished.

We rented a Jeep Grand Cherokee, possibly the worst car I’ve ever driven, and drove 500 miles home to the smell of stale cigarettes. People who smoke in rental cars should have their lungs ripped out. Fuck you.

The people at Glassman Hyundai were awesome, especially Ralph, and kept in touch with me. The good news: the motor will be replaced under warranty. The bad news: N motors are on “international backorder status.” I’m pretty much expecting October.

I had some track days coming up, so I dusted off my 1.6 Miata, which recently had HLAs serviced and new valve springs. I spent a bunch of time on new aero for that, including fitting my fastback to it.

Then I took it up to Pineview, and it dropped a valve in the first session.

So now I’ve got three broken cars and four broken engines (my race car’s engines are also currently apart) and I have nothing to drive for the PCA event coming in a few days. So I figure I’ll find a 1.6 engine, throw it in there stock, and at least I can drive something for two days at Watkins Glen.

I found a 1.6 a few hours away for $750, and tried to trace back the ownership. It was apparently Dieter’s engine once upon a time, and I get his assurances that it’s decent. So I buy the engine, take it over the Shade Tree, and have them install it. Except the engine is rusted on the inside and worthless. WTF?

Well, apparently Dieter had two engines, this one isn’t the one he was talking about. This engine used to be Stefan’s, and he pulled it out of a junkyard car and sold it before checking into it. Fucking boat anchor, that’s all it’s good for.

So now I’ve got five broken engines and no car, so I figure I’ll go to the PCA event and just do data coaching. That didn’t really work out great due to some scheduling mishaps (the classroom sessions were double booked with my data sessions), and then just a lack of people wanting to do data. So I didn’t get a chance to use my vMin coaching tools or show the slide deck I worked so hard on.

So I sat in the stands with Josh and watched turn 10 for a bit. In an entire session (20+ minutes), four people hit the rumble strip on exit. I’d say 90% of the cars left a car width or more on the exit of the turn. A good number of cars exited turn 10 in the middle of the track. Did I mention this was the advanced run group? Maybe data coaching isn’t that important.

All of this has kind of reframed what I want to do with my life. I’ve spent 12 years racing and being a prisoner of this hobby. And it isn’t just the racing I got into, there’s the instructing, data coaching, racing rules, Pineview bullshit, etc. And of course all of the aerodynamic crap: theory, building, testing, simulations, and eventually writing it down here.

I’m not sure what comes next, but I’m due a break from the chaos. One thing I’ve decided for sure is I’m no longer owning a racing team or any Miatas. I’m selling or giving away everything Miata related. It’s been a great journey, but that part of the journey has come to an end.

As soon as I’d made that decision, I felt better. My wife simply said “It’s about fucking time!”

I’m still going to write; I have a lot of unfinished drafts and some really good ones coming up. I’m still going to race, but it’ll be as an arrive-and-drive. I’m still going to track my Veloster and do a bunch of aero experiments, but it’s going to be a while before I get back to it. The future is undefined, but looks brighter already.

Just today Ralph from Hyundai sent me a little movie – the new engine is in, the car is running, and it’s ready to be picked up. Hallefuckinglujah.

My brother recently wrote a blog post on the Driving Progression, which is a Dunning-Kruger of performance driving. I thought it would be fun to do the same thing for aerodynamics.

If you don’t know what the Dunning-Kruger effect is, it’s that people with very little knowledge have a lot of confidence. They’ll freely share the benefit of their inexperience with everyone. As they gain knowledge, they start to realize they don’t know anything, and lose confidence, eventually reaching a low point of “I don’t know shit.” After hitting rock bottom, an increase in knowledge steadily rebuilds confidence to the point that they master the topic.

The D-K effect is not about being stupid, it’s about not knowing any better. That’s certainly how I started my journey through aerodynamics, and it’s probably similar to how other people got started.

I’ve identified four general stages of the D-K effect, which I’m calling Fanboi, Learning, Experiments, and Optimization.

• Fanboi – Buying aero parts for looks, drag reduction, or blind trust.
• Learning – The apple of knowledge brings despair.
• Experiments– Tools and experiments to expand knowledge.
• Optimizations – Applying aerodynamic principles to any object with good results.

Fanboi

The first phase of aerodynamics is largely acquiring parts without understanding their specific use.

• Appearance – Many people buy aero parts because they look cool. Most dealer options like a front lip, side skirts, or spoiler are early on the upward slope.
• Drag reduction – People easily grasp the concept of drag reduction, and not knowing any better, it defines the next level of purchases or DIY projects.
• Blind trust – At this point a person has bought a wing or spoiler and some other aero that has good results (I dropped 3 seconds with a wing!), and now they think more aero is better and buy it all, whether or not it’s designed well or would be useful on their car.

You can ask a fanboi why they have this aero part, or how it works, and you’ll get a reply that has nothing to do with personal aero knowledge and everything to do with blind trust in the manufacturer. Businesses have a vested interest in parting you with your money, are they really the people you should trust on this matter?

Some people never get past the Fanboi phase, and good for them, ignorance is bliss. But some of them watch a video or read a book, or god forbid they find this website, and then they fall down a very deep hole into despair.

Learning

The next phase begins when a person does actual research into aerodynamics, and thus begins a slippery slope down Dunning-Kruger’s backside. Often YouTube is their first inkling that things don’t work exactly the way they’d hoped. For example, maybe they saw Kyle Forster’s video on how wings don’t work with convertibles. Or they watch Julian Edgar read yet another bedtime story from his book.

Some people might stumble onto my Occam’s Racer website, and if you’re a regular reader, you know I do a lot of debunking and peeking behind the curtain. Other notable stops on the way to the pit of despair include Competition Car Aerodynamics, by MacBeath and the more challenging Race Car Aerodynamics, by Katz.

From there you might dig deeper into to the grandfather of texts, Hucho’s Aerodynamics of Road Vehicles, or hit the lowest point, SAE papers and peer-reviewed university studies. At this point aerodynamics, or should I say, fluid dynamics, is so full of numbers, equations, and nerd stuff that you feel you know shit-all of nothing.

Experiments

Further knowledge comes through experimentation. Just as you were once a fool to trust aerodynamics manufacturers, you’d be a fool to trust anything you read or see on YouTube. So this next phase is where you get hands-on, experimenting to see the result.

Personally I jumped right into Airfoil Tools, OptimumLap, and other free resources, then DIY’d my own projects. A more sensible approach, and one I took later, is to enroll in Kyle Forster’s (JKF Aero) online course on aerodynamics.

Most of us aren’t going to have the means to get into CFD, and so Kyle does that for you, performing the experiments you’d do, and doing a nose-to-tail breakdown of different cars in CFD. If you are serious about aero, there’s no better use of your time or money.

It’s worth noting that Kyle uses OptimumLap in his course, since it’s a great way to get instant validation on whether something works or doesn’t, and how it plays out on different race tracks. I was already using the program for years before taking Kyle’s course, and it being FREE, everyone who is serious about aero or validating any other modifications to their car should use it.

The final stop in the Experiments stage is oddly where I started: real-world testing. That could mean going to a wind tunnel, or in my case, hiring a professional to make Watkins Glen into our own personal wind tunnel. And with that hard data, one comes to certain realizations about aero, and it turns out that it’s not that difficult after all.

Optimizations

Once you reach this level of understanding, you realize it’s not about the parts, but by applying certain principles. You are either optimizing the car for a particular rule set, or in the absence or racing rules, to handling characteristics, efficiency, a particular race track, or other factors.

The principles go something like this:

• Attached flow – You want to keep air attached along surfaces. A thicker and turbulent boundary layer is better than detached. Streamlined objects have rounded leading edges and break cleanly at the trailing edge.
• Change the direction of air – If you aren’t changing the direction of airflow, you aren’t doing dick. Most often you want to send air upwards, creating an opposing force: downforce. You don’t want to change direction too much or air detaches, causing drag and destroying downforce.
• Maximize suction – Pressure is good, suction is better. Maximize suction and minimize losses to the underside of splitters, underbody, and wings.
• Manage tires – Tires are draggy, disruptive to airflow, and create a jet of air as they roll forward on the ground. Manage tire drag and squirt to mitigate losses.
• Manipulate vortices – Vortices are usually thought of in terms of loss and wasted energy, but you can manipulate vortices to create air fences, delay flow separation, reduce energy on the face of the tire, etc. At the bleeding edge of performance, like F1, it seems like most of the effort is spent managing and manipulating vortices.

Conclusion

There is nothing wrong with being on the early, upward slope of the Dunning-Kruger graph. Choosing aero parts because you like the way they look, or because you support a particular manufacturer, or because they work and you don’t care why, is a happy place to be. This covers the 90% usecase.

In reflection, I can’t think of a compelling reason to get into early aerodynamic texts or plunge into SAE papers, they can be too much. Instead, leave that shit to me, I’ll translate it for the masses and make it fun to read (I won’t say “dumb it down” because y’all are smart or you wouldn’t be here).

But if you really want to get into aerodynamics because you’re developing something for the last 10% of performance, or because you need a competitive edge, then I’d start with the JKF aero course. You’ll definitely be making your own aero parts, because the aftermarket doesn’t support the kinds of things you’ll be doing, so plan on investing in tools and materials.

This is a worthy journey, but all-consuming, and requires sacrifices. Have fun with it.

I’m going to aero the shit out of Veloster N. This will require serious head scratching at first, and then some DIY fabrication, followed by a lot of testing at low- and high-speed tracks. I expect this process to take the entire summer, with alternating gains and setbacks along the way. But I’ll eventually nail a satisfactory aero package, it’s just going to be a process to get there. So let’s start with the head scratching.

First the stats: I figure my VN weighs about 3250 lbs with me in it, and has about 64% of its weight on the front tires (2080 lbs). The rule of thumb is that aero balance should match chassis balance, and that means a 64/36 split on aerodynamic downforce. This should preserve the car’s natural handling characteristics at all speeds. As a practical matter, this means going after as much front downforce as possible, and balancing that with about half as much in the rear.

I want to figure out what that will do for the total grip of the car. I’ll start with a body that has 0.3 coefficient of lift, and assume that’s evenly distributed (in reality, it’s mostly in the rear, but I’m just doing some rough figuring here). I’ll estimate a splitter gives about 40 points of front downforce (that’s -0.4 Cl) and balance that with 20 points in the rear. That’s not much rear downforce, and I could achieve that with a very small wing, or more likely a spoiler.

I want to see what this aero package will do for downforce and grip at different speeds, so I’ll do some rough calculations based on tire grip being proportionate to weight (it isn’t exactly, but these are rough calculations).

The results show that the car will gain grip at speed and that the chassis balance will stay pretty much the same. In a 80 mph corner, this would give about 3.4% more grip, which is great.

But I don’t subscribe to the theory that I should balance the aero the same as the chassis. I’ve implemented exactly the opposite of that on my brothers Yaris race car, and had great results. Let’s see how that works out mathematically.

Dynamic rear aero balance

I like a FWD car that is loose in slow corners and tight in fast corners. This makes the car easy to turn in hairpins, neutral in the majority of corners, and stable in high speed kinks. This handling magic isn’t difficult to do, just set up the car to oversteer and use a big wing to shift aerodynamic balance rearward at speed.

There are numerous ways to get a FWD car to rotate easier.

• Reduce front roll couple – Softer front springs and/or softer front sway bar; Harder rear springs and/or stiffer rear sway bar.
• Tire grip – Reduce front tire pressure or use wider front tires or a softer tire compound. Or increase rear tire pressure, narrower rear tires, reduce rear, use harder tires.
• Add rake – Make the car lower in the front or higher in the rear.
• Alignment – There are numerous ways to use camber and toe to increase front grip and/or reduce rear grip.

So assuming that I can get the car handling the way I like it in low-speed corners, let’s see what happens when I spec a properly sized wing. In this scenario, I’m going to add twice as much downforce on the rear as the front, and this is about what a typical splitter and wing setup will do.

Just like before, I want to see how much grip the car has at different speeds. More importantly, I want to see the aero balance of the car, how much weight moves rearward, and how quickly it shifts.

What the math says is that the aero balance will change about 2% between slow corners and fast corners. That’s like putting 200 lbs of luggage in the trunk, and you’d think that would be noticeable. But the weight shift doesn’t happen that suddenly, and for most corners, I doubt I could feel the difference. In an 80 mph corner, total grip has gone up to 8.1% with the wing, which is a lot better than with the spoiler. But can I use all that grip, or will the car just push like crazy?

Hopefully it works out like this:

• In slow corners, the car rotates easily; there should be no noticeable change in rear grip or front aero balance.
• In medium-speed corners (80 mph), aero balance should shift about 2% to the rear. This is where I want the car to feel neutral.
• In fast corners, aero balance should shift about 3% rearward. I’d like the front tires to be pushing a bit, although I doubt a 1% increase will do that. Maybe I need a bigger wing for that to happen.
• At top speed, aero balance should shift about 5% to the rear. I won’t be cornering at this speed, but moving weight, drag, and the center of pressure rearward should help stability when braking.

Now that’s a lot of shoulds, and I don’t usually go in for this kind of rampant speculation. But FWD hatchback aero is mostly unfamiliar territory, and I want to explore the numbers before I build anything. Also, nerding out on this shit is fun.

No splitter, just a wing?

Splitters are a pain in the ass on a street car. In order to make downforce, they need to be close to the ground, and since they also protrude forward, they run aground. The fact is, splitters are just not practical for a daily driver.

So what about using all of this previous conjecture (set up a car to rotate in slow corners and move aero balance rearwards at speed) and applying it to a street car? Could this be as simple as not using a splitter and simply adding a smaller rear wing?

Yeah, it should be. In fact my first project is a DIY spoiler and small wing that attach on the same brackets. I’ll test them back-to-back vs the OEM wing/spoiler and see how they perform.

I was hoping to do my first real-world test this weekend at Grid Life, but it’s going to be wet, and I’m behind schedule on DIY projects. Not a huge loss, I have a lot of dates at WGI this year, and I can do the high-speed testing at the end of May.

Before that I’ve got a track day at Waterford, and I should be able to bring some rear aero options. It’ll be interesting to see if a small amount of rear downforce alone helps at a small track.

I’ve been looking into aftermarket wings for Velosters and thought I’d do a quick review. None of them are super interesting to me, so I’ll do a follow-up article when I make my custom wing.

I’ll start with the OEM wing. It doesn’t have an airfoil shape, the trailing edge is rounded, and there’s no camber to speak of. I doubt it creates much suction underneath, and so it’s not fair to call this a wing. If it’s not a wing, it’s also not a spoiler, as air certainly goes underneath it. If you filled in the gap it would be more effective at creating downforce, but it would also have more drag, which would be a lousy tradeoff on a street car.

But I’m not saying the OEM wing is useless. Most hatchacks create rear lift due to the curvature of the roof, and the Veloster N has about 10 degrees of downward slope in the rear, which is fairly extreme. By flattening out the air at the rear with the “wing”, Hyundai reduced rear lift.

In addition, adding some drag and rear surface area (end plates) moves the center of pressure rearwards. This creates a greater static margin (the distance between the center of gravity and the center of pressure), which makes the car more stable at high speed.

There is more styling than substance here, but at least the Veloster doesn’t have a shit ton of fake vents (ahem, Civic Type R).

On a wing and a prayer

Some aftermarket companies have used the OEM wing as a starting point, which makes sense if you’re trying to sell a product. It would be a lot more expensive to sell a wing complete with a new roof extension, third brake light and window washer nozzle. But while starting with the OEM wing as a base is easier, it results in major compromises. Take a gander and see what I mean.

First, this TIE Fighter wing. It’s shaped similarly to the OEM one, but looks like it has more topside camber. Nevermind that it’s the bottom that needs camber. It’s hard to tell if this is a proper airfoil shape, and the end plates are hella stupid. (Usage: The adjective hella is properly used only to modify the word stupid, and then only in relation to people who use hella in a sentence. Example: Dude that wing is hella tight! – No, you’re hella stupid.)

One thing they did do correctly was make it taller. Wings create downforce via suction, and you need space below the wing for the low pressure region to form. And on that note….

The ADRO V2 wing is a better TIE Fighter. Looking at the underside, it appears to have an airfoil shape, it has a bit of a kick to the topside, and the trailing edges are sharper. They’ve added some height to the middle of the wing, but for some reason not on the sides, which certainly won’t help. Overall, I bet it performs marginally better, but for $1400? Meh and fuck no, all at once.

Next up is the EPSILON+ spoiler extension. At $220, this is the cheapest aftermarket way to make something useful out of the OEM wing (or whatever you call it). There will be some drag increase, but the tradeoff in downforce is worthwhile (for track use). This is also the only OEM option that doesn’t look hella stupid.

Clean sheet designs

All of those options started with the OEM wing and had multiple concessions as a result. With a clean sheet of paper, and the roof extension from the base model, what kind of wing could you mount?

The first wing I found was on a first-generation Veloster. The wing mounts are quite nice, attaching to the hatchback door so that you can still get at things inside the trunk. The main problem is that the wing is mounted too close to the roof, and so there’s no room for the low-pressure zone below the wing to form. As such, this is mostly a spoiler in function.

The other problem here is that this is a 3D wing, but it doesn’t match the profile of the roofline. The whole point of a 3D wing is to make it so that air going down the middle of the car is at the same angle of attack as the outsides of the car (free stream, zero degrees). This 3D wing doesn’t match the roofline very well; the center section isn’t large enough.

I will say that the wing mounts look decent, and I plan to build something similar.

On the subject of wing mounts, what the fuck is up with chassis mounts on a hatchback? Maybe I’m missing something here, but is there any way to get into the trunk of a hatchback with chassis mounts?

Next is a proper wing with proper mounts, and it ought to be, because it’s off a TCR Veloster. Two things jump out at me right away: 1) It’s set back quite a ways, 2) how did they get the wing to not sway back and forth with those mounts?

First let’s talk setback distance. Increasing setback distance results in more space underneath the wing, and so there’s plenty of room for the low pressure zone to form. On the other hand, the further back you mount the wing, the more leverage it has, which reduces front downforce. Maybe that’s the point of it, to move the F/R balance further rearward?

The mounts themselves only attach at two points, and therefore must have some sturdy backing plates inside, because I can’t see how those are going to keep the wing from swaying back and forth on quick transitions. It’s a TCR car, so I’m sure they have that shit down solid, but I don’t think I’m going to make mine like that.

Next I should be reviewing a 9 Lives Racing wing, but they don’t have one for the Veloster. I’ll have to correct that on my own time. (Meanwhile, I often say 9 Lives Racing “wing”. This is like a litmus test for annoying; anyone who corrects me with “wáng” is a fanboi poseur.)

Next is a wing by CF Style. Mok Racing will be importing these from Korea, and they look like the best option to me. The wing appears to be a proper airfoil shape, and the only nit I have to pick is the lack of a Gurney flap.

Now a Gurney flap isn’t always necessary, the effect is pretty much the same as increasing wing angle. But if you’re cranked all the way up to 10 and you need just a little more, then a Gurney flap is how you get to 11. So some provision for that would be nice to see, as it doesn’t look like a simple piece of angle aluminum will fit that contoured trailing edge very easily.

The wing is mostly a 2D shape, which is fine considering the wing doesn’t stick out into free stream air, or at least not far enough to require twisting the ends down. I don’t have the dimensions or pricing on the wing, but will fill that in when those arrive.

If you look at the wing mounts, they appear to be as short as you can make such a thing, and so probably very stiff and light. The setback distance isn’t as far as the TCR, but that may be preferable for most of us, who don’t want to shift aero balance too far to the rear. All said, this wing package is a 98 out of 100, and if I was looking to buy one rather than make one, I’d buy this one.

But of course I’ll make one.

I look at airfoils a lot, comparing different shapes at various speeds and angles of attack. It’s a nerdy and pointless exercise, because Miatas are limited by front downforce; trying to get the most out of the rear is rarely necessary.

Of the commercially available wings, 9 Lives Racing’s extruded aluminum wing is the best bang for the buck, and nobody is going to feel bad about that purchase. The Big Wang is built apocalypse-strong, and you could probably run a front wing as a bumper. With that strength comes weight, and that’s the only nit I have to pick.

At .2 lbs per inch, a Miata-sized 64” wing weighs 13.2 lbs, and when you add wing mount and end plates it’s close to 20. This isn’t all that much weight considering the benefit you get, so what am I fussing about?

It’s where the weight is. Put that weight down low in the center of the car, and it wouldn’t matter. But put that weight at roof height, at the far end of the car, and that hurts fast changes of direction.

Try this: Imagine running around your yard like it was an autocross track, holding a broom out in front of you. Now do that again with the broom held close to your chest. Much easier! Mass centralization is important for fast changes of direction, and weight at the polar ends of the car, or high up, is bad.

I race a time trials series at Pineview Run, which is a very tight road course with 15 turns in one mile. It’s a bit like an autocross course, but with elevation and camber changes. With so many fast changes of direction, I’ve had better results with a spoiler than a wing. Mathematically, the wing is making more downforce and I should have more grip than when using the spoiler. But the stopwatch doesn’t lie, and I believe the reason for that is entirely the weight and location of the wing.

So I got to thinking about it, and I figured I could build a lighter wing. I’d also make it narrower, which would help a little for mass centralization. But I’d need to increase the chord to so that it had similar overall downforce.

I started with the 9 Lives Racing “Mini Wangs“, which are cutoffs from their factory. I traced the 9LR wing profile onto two pieces of 1/4” aluminum plate, and cut them out on a band saw. I then drilled one side of the Mini Wangs and tapped them for a M6 bolt, and drilled through the other. Next I simply bolted them together. These would serve as my wing supports, as well as the support for my end plates. No welding, easy peasy, and someone could easily do the same upside down and make a swan neck mount.

Next I took a strip of 48″ of aluminum (street sign) and bent an angle on it. This made a 2.5″ extension that I wedged into the 9LR Gurney flap slot. (I had to cut the vertical part of the slot off.) This would act as both the Gurney flap and the chord extension. I used the extension/flap to join the two “book ends” I’d made, and added a center support using another 9LR Mini Wang. For the nose of the wing, I used 1/2″ aluminum tubing, fastened into the bookends and center mini wang.

Next I took a skateboard laminate (single ply of maple that bends easily and takes epoxy well, and I happen to have a lot of these around because my buddy Jason owns Comet Skateboards) and epoxied it over the underside of the wing. I strapped the whole thing down with clamps and let it cure.

Then I flipped the wing over, added some supports on the inside, and glued another skateboard laminate to the top. I then fiberglassed the whole thing with 6 oz fabric.

The end result is a 9LR wing with more chord. Ideally I would have made it slightly thicker (to preserve the same shape airfoil), but cut me some slack here; I’m literally gluing a skateboard deck and a street sign to scrap metal.

All told this wing cost me about $70 in materials and a few evenings of labor. But I have a lot of experience with fiberglass and weird shit laying around (like Comet skateboard laminates, street signs, microballoons, etc.), and someone else buying all the materials and having less experience would double the cost and effort.

One Louder

I was trying to come up with a name for the wing. It measures over 11”, which reminded me of the quote from Spinal Tap, “this one goes to 11.” So I’m calling it the Marshall wing, after the guitar amp.

The Marshall has 9% less area than the typical 64″ 9LR you’d put on a Miata, and should have about the same amount of downforce as a 58” 9LR wing. I used a 60” wing on my fastback Miata, so that’s in the same ballpark.

However, at 48″ wide, the ends of the wing are not in free-stream air, and the close proximity of the wing stands and end plates is going to cause more drag and probably some loss in downforce to turbulence. My guess is that behind a standard Miata hardtop, this wing will make 15% less downforce than a regular 9LR wing. Mounted behind my fastback, it’ll be fine.

The important part is that the Marshall weighs just 7 lbs, including the beefy 1/4” wing mounts. This is about half of what a 64″ 9LR wing weighs, and that was the point of this project.

End Plates

If you’ve read my article on DIY end plates, you know that end plates are about the least important thing you can optimize on your car. A good rule of thumb is to make the end plate rectangular, and about as deep as the chord.

I made these end plates from a 10 MPH street sign. I started with a rectangular shape that would leave a number 10 on one side, and the initials MPH on the other. I rounded the bottom corners so I won’t cut my head open reaching for a tool under the car. I made a relief cut on the top to bleed some high pressure air on top of the wing and reduce drag, and then made a cut on the top back corner to lessen the vortex there.

But the real reason I chose this end plate shape is simply to preserve the serif on the number 1. This is how much I care about end plate design these days, I’m letting the sign graphics dictate the shape.

Double Wing – Marshall Stack

My single-element Marshall wing should work for high speed tracks where a reduction in drag might be useful, but I really made this for Pineview Run, where the average cornering speed is in the 40s. For that speed, I could use maybe even more chord and more camber. The easiest way to do this is to stack a second element onto the existing wing. That’s right, I’m calling this the Marshall Stack!

I have a couple made-in-China wings kicking around my shop. I’ve modified the bottom profile to fill in gaps and add roundness, and it’s now a custom profile. I went looking for a similar profile on Airfoil Tools, and the closest I can find is the WORTMANN FX 72-MS-150B shown here at zero degrees. I reviewed that wing in a previous article, no need to go into the details here.

Gurney Flap and End Plates

I want to put a Gurney flap on the upper blade. On airplane wings, the standard formula for Gurney flap height is 1-3% of the chord, but on cars you typically see 5% and even up to 10%. The MIC wing has a 5.6″ chord and 5% of that is .28″ which is close enough that I’ll call it 1/4″.

I can adjust the main and secondary wing angles, so I don’t think it’s necessary to have a removable Gurney flap, so I riveted 1/4″ angle aluminum to the top of the wing and called it done.

You may recall that the main wing already has a Gurney flap, it is in fact an integral part of the entire wing structure! But can you use a multi-element wing with Gurney flaps on both wings? Yes. I’ve read a couple scientific papers (1, 2) on the subject, and it definitely creates more lift, but it’s finicky.

There is risk of turbulence and flow separation at the main wing’s Gurney flap, and this appears mostly dependent on the size of the convergent gap between the wings. Which is also dependent on the size of the Gurney flap. To quote Catalano “The use of Gurney flap at the trailing edge of the main element is highly dependent on the gap and overlap optimization.”

To hedge my bets I did two things: First I reduced the size of the main wing Gurney flap to 2% of the chord (about 1/4″); Next I drilled two sets of adjustment holes in the end plates, one to create a smaller convergent gap, and one for a larger gap. I can now adjust the gap size vertically and see which works better.

The secondary wing is supported entirely by the end plates. I made some new ones from street signs following MacBeath’s pressure plot of a double wing.

To cover the low pressure zone, you can see that the end plate doesn’t need to be extend aft of the upper wing. Most of the low pressure (suction) zone is low and in front of the main wing. My rule of thumb is to make end plates as deep as the chord of the wing, but when I mocked them up, it just looked stupid. I know that larger end plates would probably perform better, but sometimes you have to make concessions for appearances.

MacBeath and others have suggested 2nd element angles of between 20-40 degrees, and so I drilled three holes to allow 10-degree increments on the upper wing.

Triple Stack?

Using another MIC-wing and street-sign end plates, I added a third wing on top. I tested it at Pineview and it worked even better than the double stack. But it looks so fucking ridic I’m embarrassed to be seen with it in public.

But this construction method proved strong and light, and my next project is a 3D wing for my Veloster N. Subscribe to the blog if you want an update when that happens.

I just bought a 2022 Veloster N, 6-speed manual. Naturally I’m going to aero the shit out of it, which will bring new hatchback content to this site. All of the Veloster articles will have Veloster in the title for easier searching (and so Miata people can ignore it).

Why a Veloster N?

Last August I decided I wanted a new car because driving a couple hours to and from a track in my Miata was loud and uncomfortable. Yeah, I’m that old. I put a deposit on a 2023 BRZ, but after 6 months of hearing nothing from the dealership, I got my deposit back. It wasn’t just the waiting game, but I realized I don’t want a Subaru engine in anything, and I also want a front-wheel drive sports car for a change of pace.

I’ve owned several FWD cars in the past (Corolla Tercel, EF Hatch, EF wagon, 10th gen Civic, Mini Cooper), and have raced my brother’s Yaris a number of times, and FWD has different capabilities that makes driving interesting. Compared to RWD, FWD is faster in the wet, better in the snow, but is generally slower on track. At Pineview Run, FWD is really fucking slow for some mysterious reason. And therein lies the challenge.

I did a lot of research on FWD sports cars and my top three were the Veloster N. a K24 Civic Si and a Mini Cooper S (or Coupe). The Veloster N is certainly the fastest, but more importantly, it reminds me of the CRX I always wanted in my youth.

I’ve tracked a couple

I’ve driven a couple Velosters at Pineview Run. One of my oldest and bestest friends, Chris Gailey, has let me track his VN at Pineview. The car impressed the hell out of me, and I reviewed it and other cars in Driving Other People’s Cars in 2020, and said this about the VN:

If I was going to buy a new car tomorrow I’d buy a Veloster N. This is coming from a Miata guy who was teetering on quitting racing and buying a ND2. Yeah, the Veloster is that good. I would roll the fenders flat and fit the widest 18″ wheels and tires that would fit, add a splitter and a wing, and fucking dominate.

It took three years, but the plan remains pretty much the same. Except that it’s not easy to fit really wide wheels and tires. Most people have only increased the width by half an inch and are on 18×8.5 +45, and use a 235 or 245/40r18. I waffle back and forth on which way to go on 18″ tires, but if history has taught me anything, then I’ll probably have a dozen wheels in my basement this winter.

On the OEM Pirelli PZ4s I was able to do a 1:17.767 at Pineview Run. I’ve gone a couple ticks faster in my Miata on Continental ECS, and so around this tight track, the VN isn’t any faster than a modified NA6. On Falken RT660s I did a 1:15.565, which is a bit faster than I’ve done in my Miata on RS4s, so again, the Veloster is probably slower than my Miata on equal tires. I suspect this will only hold true at Pineview, and at longer tracks the VN will come into its own.

But check this out, driving that bone stock VN on RT660s, I was only .25 seconds away from the all-time FWD lap record! As a data point, here’s me driving a VN at Pineview on the OEM PZ4s (red) and RT660s (blue). Lateral grip was better on the Falkens, but I also backed up the corners a lot better.

Admittedly the VN isn’t a Pineview car, and I bought it mostly for coaching at bigger tracks like NYST and Watkins Glen. I’ll be data coaching at those tracks a dozen times this year, but I also want to hit a few tracks that are further away.

Meant for track use

The N stands for Nurburgring, because that’s where the car was developed.

The user manual doesn’t have a bunch of warnings about not driving on race tracks, it assumes you will.

Warrantied for track use

Back in the day you could change the brake fluid and brake pads to higher temp versions and track just about any car. These days it seems like every car overheats on track, has nannies that spoil the fun, or is otherwise unsuitable for track use. Many new cars also stipulate that if you track them or compete in a timed competition, you void the warranty. This even applies to autocross.

There aren’t many new cars that are warrantied for track use. I believe all Porsches are, the Camaro 1LE is and… the Veloster N. From the factory: “Since the Veloster-N was designed for high performance at home or on the track, track utilization alone does not void the warranty.”

Most track cars get modified a little, and if you reprogram the ECU or use a piggyback, install an aftermarket blow-off valve, increase boost, change the turbo, etc., that will void the Hyundai warranty. But you can add a cold-air intake, bigger intercooler, oversized throttle body, and things like that and you’re still covered under warranty. I’m going to drive it without any mods, as it already has 275 hp (about 235 to the wheels according to most dynos), and that seems like more than enough.

Hyundai has a 10-year, 100k mile powertrain warranty, and because I got a Hyndai-certified used car, I was able to get bumper-to-bumper coverage for that entire duration. This is based on the original purchase date of the car, so I can beat the living shit out of this car until November of 2031 and if anything breaks, it’ll be someone else’s problem. That’s pretty incredible, and maybe more of a reason to own this car than everything else put together.

Insured for track use

I did the most adult thing I’ve ever done: bought track insurance. I used a company called OpenTrack because they have an annual policy, whereas Lockton and Hagerty are a la carte, and would require a new purchase every track day.

Total cost was about $3100 for the year, with a 5% deductible. This covers me for unlimited track days in my Veloster and my Miata, and a second driver. Wait, what?!? For realz. I can specify a second driver for any event and they are covered in my car as well.

Pre-delivery purchases

I’m still waiting for the car to arrive, but before that, I’ve already purchased a few things:

• Brake pads – I don’t like the squeal of race brakes, and prefer a pad with a lower mu, but I also need high temp resistance. I used to get StopTech 309-series pads, but since changing manufacturing plants those pads are now utter shit. So in the end I went with Porterfield R-4E, which is a pad I’ve used before.
• Tow hitch – I may tow my motorcycle or a teardrop trailer, or add a bike rack. The hitch is also a good jacking point, and I might find a way to use it as a base for a diffuser.
• Base model spoiler – I’m going to add a big wing in place of the OEM one. The base model Veloster has a simple roof extension without a wing, which won’t compromise my mounting options.
• Camber bolts – High performance tires require a lot of camber, and I’ve read that people have damaged the OEM shocks by using adjustable top hats. Crash bolts don’t seem to have the same problem, but also don’t allow as much negative camber. The bolts do reduce inner suspension clearance slightly, so this may affect future wheel decisions.
• Oil cooler – If the engine breaks in the next 10 years, Hyundai will fix it, but it’s still worth taking care of. An oil cooler should help everything last longer, so I splurged on a nice one.
• Wheels and tires – For dedicated track use, I got Konig Countergram 18×8.5 +43 wheels and Kumho V730 235/40r18 tires. Most people seem to go with 245, but 235 is closer to the standard diameter, and wider tires are not always faster.

Once I receive the car I’ll do some shakedown runs at the local tracks (NYST, PV, WGI) and get baseline data. And then the aero fun begins.