Articles

When it comes to turbocharged or supercharged engines, running on gasoline dictates that an intercooler will almost certainly be part of the equation. But what an intercooler actually does, and how to determine what parts you’d need for a build can sometimes be a bit of a mystery. At its essence, an intercooler is a heat exchanger. In an air-to-water intercooler, the heat exchange occurs between the air coming in and the water flowing through the intercooler–the heat from your charge pipes is...

V-Band clamps and flanges make for ideal tubing connections in exhaust applications, especially when the connection requires frequent disassembly. Used extensively in space vehicles and satellite launch systems, they have proven themselves in racing applications including high pressure turbo applications. The V-band connection gained popularity in CART racing and is the preferred connection for many turbo-housings. They are also an excellent choice for normally aspirated exhaust and for intak...

A Melodical Sound Hope you are enjoying these articles on exhaust header design. Building headers from mandrel-bent stainless tubing using proper fabrication techniques is important, but proper header design is crucial. Last month, we considered 180 degree exhaust headers for V-8s. As discussed, the 180 degree concept was developed to help even out the exhaust pulses from an uneven firing 90 degree crank V-8 in order to broaden the engine power band. The concept was very successful as illustr...

Muffler Technology – Part 2 Sound Reducing Technology In the last newsletter, I discussed sound and sound level measurements as related to motorsports. Since then, I have learned of additional tracks that have instituted sound rules including the drag strip at Fontana Speedway. And if you ask me, I cannot imagine why anyone would complain of noise there (Figure 1)! The sound level at Fontana is reported to be 82 dB, 10 dB lower than at Laguna Seca!  And we’ve seen some wild muffler setups t...

Muffler Technology – Part 1 Sound Measurement Over the past few years, as residential homes have been built closer and closer to race tracks, there has been a strong movement towards reducing the  sound from race cars. At some tracks, such as Laguna Seca in California, the sound limits have become so low, 92 dB in this case, that some street cars with OE exhaust systems will not pass without modification. Case in point is a late-model Porsche 911 GT3 (997). The OE exhaust is equipped with va...

You are likely familiar with the Burns Stainless double slip merge collectors used in many top-notched racing turbo-exhausts. But did you know that the double slip concept is also an excellent choice for many naturally aspirated applications, particularly street cars and other fuel injected applications. The purpose of the double-slip collector is to minimize exhaust leakage, while allowing for a slip-on collector. A slip-on collector is often times preferred over a weld-on collector for ease...

We often get questions regarding welding stainless steel, so we thought we would put together a compilation of these with answers.

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...

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...

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...