Bottom Feed Air kits: The hidden aero advantage explained:
What you need to know first is that aerodynamics is just as much a science as it is a black art. Ask any pro who has spent a lot of time in a wind tunnel and they will tell you any "tunnel experimentation usually leads to more questions than answers."
Oh, there are trends that aerodynamics rely on to make their large steps, and lots and lots of data to help show if a change was good or bad, but even with all that, the business of airflow is far from specific.
Frontal Area - A two-dimensional representation of the front surface area of a vehicle (imaging looking at a vehicle from the front from a long distance - what you would see is the frontal area).
Aerodynamic Drag - A representation of the friction between a vehicle surface and the air flowing around it.
Aerodynamic Downforce - A force resulting from managed airflow that increases the friction between the tires and the surface of the road. This force has nothing to do with physically adding weight to a vehicle, it is just a downward force that is a product of airflow.
Aerodynamic Lift - The opposite of downforce. Life is usually the result of unmanaged airflow creating an upward direction force that actually reduces the friction between the tires and the road. Lift can also result from an excessive amount of air flowing under the vehicle; actually pushing the vehicle up.
Laminar Flow - This is the most desirable type of airflow over a body in motion as it allows for the maximum downforce benefit with the minimum drag impact This term means air is flowing in a linear fashion over the shape of the vehicle. The opposite of this would be turbulent flow.
Boundary Layer - This is a layer of air that is located just off the surface of a vehicle's shape.
Bernoulli's Law - A rule proven with mathematical equations that explains how a shape creates lift. The law is basically that an upward force is generated when more air travels over a wing-like shape than under it. This upward force is achieved because it creates a low pressure area on top of the shape.
Bottom Feed Air Aero
TechAFX utilizes a team of Engineers from the production vehicle world that have over 50 years of experience. Our products are developed to look simple, honor the original shape of older vehicles, yet provide dramatic performance improvements. Our team has extensive experience in both auto racing and production vehicle development. Bottom Feed Air products 'work' due to these pros guiding the final shape and structure of our products. Our goal with Bottom Feed Air is to dramatically improve three aspects of your vehicle:
1. Reduce the coefficient of drag
2. Improve the aero downforce the vehicle is experiencing.
3. Increase the laminar airflow through the heat exchangers
These improvements lead to increased miles per gallon performance, improved grip at high speeds and reduced power-train temperatures.
So is achieving these goals possible with the Bottom Feed Air aerodynamic products? The simple answer is YES!
Even better, the 'cost' of achieving these goals is relatively free. Once you have purchased and installed a Bottom Feed Air aerodynamic product, it should not require any more investment to provide it's improvements! How many products can you install on your performance car that will achieve that?
We will continue to add more information here as questions come in to our website, so check back to learn more about aerodynamics and how to improve them on your Pro Touring car in the future.
Old-School Aero Testing
There are many tests performed on Bottom Feed Air products: some simple, some complex. This is one of our more simple tests and was performed early in the development of the Bottom Feed kits to quickly see if there as a low-speed advantage to them. As you can tell by looking at the yarn tufts on the spoiler of this early Camaro, there is a dramatic advantage. Most of the air that would have normally just traveled under the vehicle is now either going through the heat exchangers (radiator, a/c condenser, power steering cooler, etc) or around the sides of the vehicle. And that action starts almost from 1 MPH!
We'll share a little more on our testing as time goes on, but this should be enough to get you thinking of how much aerodynamic advantage is available with Bottom Feed Air products.
AN thread (fittings)
From Wikipedia, the free encyclopedia
A 37° flare type end fitting for flexible hose
The AN thread is a particular type of fitting used to connect flexible hoses and rigid metal tubing that carry fluid. It is a US military-derived specification stemming from a joint standard agreed upon by the Army and Navy, hence AN. The standard is sometimes mistakenly referred to as "Air Force-Navy", but it dates back to before World War Two, before there was a separate US Air Force. (circa 1937)
AN sizes range from -2 (dash two) to -32 in irregular steps, with each step equating to the OD (outside diameter) of the tubing in 1/16" increments. Therefore, a -8 AN size would be equal to 1/2" OD tube (8 x 1/16 = 1/2). However, this system does not specify the ID (inside diameter) of the tubing because the tube wall can vary in thickness. Each AN size also uses its own standard thread size.
AN fittings are a flare fitting, using 37° flared tubing to form a metal-metal seal. They are similar to other 37° flared fittings, such as JIC, which is their industrial variant. The two are interchangeable in theory, though this is typically not recommended due to the exacting specifications and demands of the aerospace industry. The differences between them relate to thread class and shape (how tight a fit the threads are), and the metals used.
Note that 37° AN and 45° SAE fittings and tooling are not interchangeable due to the different flaring angles. Mixing them can cause leakage at the flare.
|Tube OD (Hose ID)
|SAE thread size
|Pipe thread size (NPT)