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A gas at a higher temperature flows faster than
one at a lower temperature because it has more energy. In an exhaust
header, a higher flow rate can extract more leftover combustion waste
and pull more fresh mixture into the combustion chamber. One way to
increase the exhaust header heat is to wrap the header with a material
designed to hold the heat in the pipe.
On our Fastruck project racer, we used header wrap on our DynaTek headers. These headers, by the way, are the crossover type. The left header crosses over the transmission and behind the distributor. The two sides come together at a "Y" on the right side of the transmission, and then a single pipe channels the exhaust out of the right side. We are required to run a muffler at some tracks, so we decided to make the DynaTek muffler a permanent part of the installation. DynaTek recommended this setup for our engine and the tracks where we run. We extended the header wrapper all the way past the end of the muffler to get maximum effect of the wrap. This also keeps the area under the hood and beside the driver cooler. A more comfortable driver on a hot summer afternoon will be in better shape during the last part of the race. Kim Scheffler-Bennett, our Fastruck driver, was given the job of wrapping the Dynatek headers. She had little trouble with the stainless ties.. She wrapped about two turns from the flange and then stopped to put on the stainless ties, which function like a plastic tie-just pull them tight and cut them off.
The header flange, when off the car, was clamped in a vise in a way that prevented it from interfering with the process. I don't recommend doing this job with the header in your lap. Kim had never done this job before. I gave her little instruction, simply telling her to "overlap it 1/4 inch and wrap it tight." You should start the wrapping about 1/4 inch from the flange to allow clearance for the header bolts. In one evening, she had wrapped the DEI (Design Engineering Incorporated) material onto both headers.. She did a neat job of it, too. A pair of snips and a pair of pliers were the only tools needed for the job. Our DynaTek headers were new. If yours are old, the use of a wire brush and a coat of high-heat paint, such as VHT, would be a good idea.
When wrapping an existing header installation, do not wrap over oily areas. Enclosing the oil can potentially cause a fire. In the Honda, I used non-flammable brake cleaner on the pipe surfaces under the engine before I wrapped the pipes. The Honda pipes were wrapped to the end of the collector, which was also the end of the exhaust system. Although I haven't been told, the wrap seems to be made of a Kevlar/fiberglass weave material. It is definitely resistant to the heat from a header pipe. Thermo-Tec says its header wrap was purposely designed to not over-insulate the exhaust system.
Paint that allows the wraps to keep their appearance is now available. The paint also protects from oil absorption. Header wrap is available in two colors, black and tan. Thermo-Tec has a copper-impregnated wrap, giving it that same color. Plastic tie-wraps for temporary use help to make this a foolproof job. It is not difficult to wrap new headers before they have been installed. Headers that are already installed can be wrapped with a bit more care. Clean old headers with brake cleaner, a wire brush, and a coat of high-heat paint. Proper wrapping (1/4-inch overlap) promotes the right amount of heat insulation. Like they say when finishing the making of a movie, "That's a wrap."
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| *******On this website I am sharing the things I find out along the way. I do not guarantee that these modifications will work on your specific vehicle, any damages caused as part of the installation or use of these modifications are the the responsibility of the person who performed the installation. | ||||||