DEI Pipe Wrap Test: IronWorks Magazine
Deflects heat, but what about performance?
STORY AND PHOTOS BY PAUL HOLDSWORTH
With 3800 miles on the FXRT, the heat from the un-shielded SuperTrapp exhaust system needed a solution. It was a foot cooker. We opted to try pipe wrap from DEI as a fix. Working with Mike Witt, dyno tuning guru at Chicago H-D, we soon had my header wrapped up tidily in a short period of time. After a test, I realized it helped a great deal with the exhaust system heat. All I did afterward was to put a small heat shield on the wrapped pipe so that my boot heel would not melt on it, nor would constant rubbing from my heel wear through it. A protective silicone spray is available that seals the wrap and allows you to clean it with soap and water, keeping the wrap looking new.
The wrap cured my cooked dogs, but did it affect performance? Coincidentally Mike owns an FXRT with a Supertrapp system and faced the same hot pipe issues as I did. He took his exploration a step further; wanting to learn what impact pipe wrap might have on performance.
Equipped with the right tools—a dyno and exhaust analyzer—Mike learned that a wrapped pipe retains heated exhaust longer, delaying the point where cooled exhaust gas begins to back up the flow in the pipe. Keeping exhaust gas hot affects pipe scavenge and exhaust gas velocity. As a result of the wrap the engine ran leaner, allowing Mike to enrichen the jetting. Adding more fuel increases power: i.e. more fuel contributes to cooler running temperature. A dyno pull between jet changes monitored the increase in power and torque. Not a great increase in either, but enough of a difference to be noted. We measured a HP increase of 1.13 and an increase in torque of 3.31 ft./lbs. That’s not a bad return on an investment of about $40 and a few jetting changes.
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