Articles
Welding FAQs
We often get questions regarding welding stainless steel, so we thought we would put together a compilation of these with answers.
Are We Ready To Weld Yet? - Part 5
We have our TIG welder ready to go. We have our header tubes tacked together with perfect fitment. We have properly fit the pipes to the flange and have our back purge system setup. So you may ask, are we ready to weld? Yes, we are finally ready to weld up the header. It is worth repeating that a well fabricated header is the result of many hours of diligent planning and preparation. I often get calls from customers who want to fabricate headers who tell me "I can weld stainless." Not to take...
Welding Exhaust Systems - Part 4
So we are now finally ready to weld. Well, no, not quite. In the past few issues of the newsletter we have discussed various welding techniques, tube fitment and backpurging. As you can see, the key to a proper header build is attention to the details. In this installment, we will discuss the proper treatment of the flange/exhaust port interface as this is a critical point and can make big differences in header performance. One of the most critical areas of concern in an exhaust header is the...
Welding Exhaust Systems - Part 3
In Part 2 we discussed the importance of tube fitment when fabricating headers. This month, we will discuss techniques involved with back purging exhaust tubes. When heated to welding temperatures, alloys such as stainless steel and Inconel are prone to the formation of oxides if not shielded from oxygen present in the air. Technically known as "sugaring" or "noogies," these oxides will result in a poor weldment, characterized by a black, crusty appearance of the weld metal on the inside (roo...
Welding Exhaust Systems - Part 2
As mentioned in Part 1 of this series, TIG should be employed when welding thin sections of exhaust tubing, especially when using specialized alloys such as stainless steel or Inconel. The header in Figure 1 is an Inconel Pro-Stock header fabricated by Jack Burns from 0.028" wall tubing. The considerable control of the welding process by the operator and the inert shielding gas help assure proper weld strength for these alloys that have a propensity to form unwanted oxides during heating. Thi...
Welding Exhaust Systems - Part 1
Welding is one of the most important fabrication techniques in motorsports. Today's race shop welders need to be well versed in applying welding techniques to various applications and materials including steel, chrome-moly, stainless steel, aluminum and even exotic materials like Inconel. As there are numerous excellent sources of information on welding, including the American Welding Society, this series of articles is not intended to be a thorough examination of the topic. I would only lik...
Detailed Header Construction insights and tips
When constructing racing headers, it is very important to make a logical plan before cutting any tubing. The design selection is the first step. Typically, the easiest and quickest way to ensure a good design choice is to use an existing, proven design as a basis for your new header. At this point a mock-up is unnecessary and you can proceed to making the actual stainless header. If, however, you are starting from scratch then a new design is called for. The best bet on a fresh design is to c...
Exhaust Header Theory
In order to explain the effect of exhaust tuning on performance, let’s take a quick look at the 4-stroke engine cycle. The first step in the 4-stroke process is the intake stroke. With the intake valve open, the piston travels down the cylinder pulling a fresh air and fuel mixture into the cylinder (intake stroke). When the piston nears bottom dead center, the intake valve closes and the cylinder travels up the cylinder compressing the air/fuel charge (compression stroke). With the piston...
Inconel
Inconel® refers to a family of trademarked high strength austenitic nickel-chromium-iron alloys that have exceptional anti-corrosion and heat-resistance properties. These alloys contain high levels of nickel and can be thought of as super-stainless steels. Inconel alloys are used for a variety of extreme applications including navy boat exhaust ducts, submarine propulsion motors, undersea cable sheathing, heat exchanger tubing and gas turbine shroud rings.
For many years, Inconel has been us...
Merge Collectors
Burns Stainless Merge Collectors are highly respected by many engine builders including NASCAR, and are widely used by champions in NHRA, IMSA, FIA-GT, and V8 Supercars.
Burns Stainless Merge Collectors (Header Collectors) are custom engineered for each application using our proprietary X-design parametric custom exhaust design computer program. Merge Collectors combine high flow and high velocity to increase and broaden an engine's torque curve all the way to the horsepower peak and beyon...
Yield Strength
A question I am often asked is “why don’t you recommend aluminum for an exhaust material?” They continue, “so-and-so" has been running it on his car for years without any problems.” So let’s take a closer look at this topic. Exhaust tubes experience stress from a variety of sources including thermal stress, vibration, exhaust pressure, hitting the ground (usually when loading car on trailer), chassis bind etc… The combination of these stresses result in an applied stress to the tube material....
Bundle of Snakes - 180 Degree Headers
Many of you have seen the so-called “bundle-of-snakes” headers on the infamous Ford GT40s of the late sixties, but you might wonder.
Are they still relevant today?
Those beautiful works of art built by English craftsman on the Lola-designed chassis where two tubes from each bank of the V-8 are crossed over the engine to collect in 4-1 collectors with opposing tubes.
