This is a list of books and other resources I frequently reference.
The grandfather of all aero texts is Hucho’s Aerodynamics of Road Vehicles: From Fluid Mechanics to Vehicle Engineering. It’s expensive, but worth it. When you see black and white drawings or graphs and you’re not sure where they came from, it’s probably from here.
Competition Car Aerodynamics, by Simon McBeath is an outstanding guide to both closed- and open-wheel race cars. The 3rd edition includes information on computational fluid dynamics (CFD), and it’s the one to have.
McBeath has another book called Competition Car Downforce, and it has similar information, but less of it. There’s a lengthy DIY section on building your own wings.
Practical Racing Aerodynamics by Robert Tarzwell is exactly what the title says it is. It’s not full of formulas or CFD tests, but real-world knowledge from a racer. This is a great book if you want to take his advice and get to it. But I like to nerd out and know why, and this book doesn’t always tell me. But it will probably serve the average car builder just fine.
Race Car Aerodynamics, by Joseph Katz, is more technical, but still pretty accessible to the non-mathematicians among us (me). He also goes into great depth on wings and airfoil shapes, and if you’re a more technical person, you’ll love this book. It’s really well written and I reference this book all the time. Katz has published many scientific papers, which he often cites as references. Not in a pigheaded way, it’s just proof that he knows his shit.
Once I started using OptimumLap, I stopped using anything else. Mostly because I like going around a race track, and OptimumLap is the best way I have to simulate that. It’s free, and easy to use. Have fun with it.
HP Wizard is a deep online resource. I particularly like playing what-if with their drag calculator. They have performance calculators, but nothing like OptimumLap.
For calculating top speed, drag losses, and the like, I use the RSR Bonneville Aero-Horsepower & Drag Loss Calculator. There are probably others, but I’m a bike guy, and I like to scroll through bike pictures.
Airfoil Tools is a library of wing shapes, calculators, and tools that allow you to compare wings, or create your own wing shapes and plot them. If you’re curious about wing design, this is an incredible resource.
In their December 2013 issue, Grassroots Motorsports did an article on how to calculate drag doing coast-down testing. Download their Excel spreadsheet and plug in the highlighted numbers for Weight, Start Speed, End Speed, Time, and Tire Size. I’ll use this calculator for coast down tests when I get around to that.
The Miata Turbo Aerodynamics forum has a lot of great info, and is growing all the time. The forum started as a single thread called Post your DIY aero pics, and it’s the best source of DIY Miata aero anywhere. You’ll need patience to sort through 90+ pages, and my frustration with that is half the reason I created this website. The sticky on this forum, Aerodynamics Section: Intro & History is a must-read. A note on Miata Turbo, it’s not a noob-friendly site. If you want to ask dumb questions, go elsewhere.
Flow Field Features and Aerodynamic Drag of Passenger Cars looks like it was created as a presentation, and this is a PDF version of it. It may be a bit older, but has a lot of great illustrations (some from Hucho) and simple explanations for reducing drag and lift.
Build Your Own Racecar has a section dedicated to aerodynamics, with simple and easy to understand concepts and to-dos. You won’t find a lot of technical details here, but it’s solid advice.
The Ecomodder website and forum isn’t really a source for racers, and I’m sure most of the members look down on racing as a waste of gas. But this is a great place to find information about drag reduction, and there’s a lot of great DIY and experimentation going on.