May '17

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68 THE SHOP MAY 2017 TECHNOLOGY & ELECTRONICS M uch has been discussed about the ben- efits of ethanol on performance. The fuel's inherently higher octane rating gives it a resistance to detonation. And less deto- nation can mean more aggressive ignition timing and more boost. That means, in the immortal words of Tim Allen, more power! One non-scientific experiment you can try is to take a drop (just a drop for safety's sake) of gasoline and place it on your skin on one hand. On the other hand, place a drop of ethanol. You'll be able to feel the cooling effects of ethanol much stronger as it evaporates. The typical ethanol blend widely avail- able at the pumps is known as E85. E85 is a mix of approximately 85 percent ethanol blended with 15 percent gasoline. Or, as you may know it better, the fuel touted by the OEM vehicle manufacturer it can safely drink with the emblazoned Flex Fuel badging. The main downside to E85 is it is a less power-dense fuel compared to gasoline. Among surveys with drivers who switch, they notice a 20- to 30-percent drop in overall fuel economy. However, in the performance market, if we are getting 12 mpg anyway, would the owner care if fuel economy dropped to 9 mpg if there were significant performance benefits? KEEPING IT CLEAN Dr. Andy Randolph, chemical engineer and the engine technical director for Richard Childress Racing, recently discussed the benefits of ethanol on performance. "Octane is the major factor against detonation," notes Randolph, "and most people do not realize that straight ethanol (or E100) would be about 113 octane. E85 that is typically sold at major gas stations comes in at 105 octane." That is a far cry from the 93 or 94 octane we are used to with the premium gasoline blends we buy at the pump. This extra octane can be harnessed for more perfor- mance without the hassle and expense of looking for race gas. However, there are two caveats. The first is the engine should have been built in the last 15 years. According to Randolph, "The auto- makers knew that ethanol blends were coming around the year 2000, so anything built after that, there is no worry about seal degradation." Second is that the fuel system needs to be able to flow more liquid, so to speak, when using E85, since E85 requires a larger volume of fuel to be injected into the intake manifold or combustion chamber. In NASCAR where Randolph develops engines, leaded gasoline was still used until A perfect combination? Usually! By Brett Solomon The Performance Factory dyno room shows that newer engines can reap the benefits of ethanol blends. (Photo courtesy The Performance Factory)

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