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Drag Racing With E85

By: Quick Fuel Technology | 05/18/2017 < Back to Blog Home
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Green Is Mean - E85 Isn't Just For Tree-Huggers

Uncle Sam wants you to drag race. Why else would he help pay for your race fuel? As a renewable energy source championed by environmentalists, racers often think of E85 as a wimpy fuel that has no place in a drag car. However, many bracket racers have shattered that perception by taking advantage of E85’s incredible 110-plus octane rating and dirt cheap pricing. E85 represents one of those rare occasions where racers come out on top when it comes to governmental decisions. As an alcohol-based fuel, the cooling effect of E85 on the air/fuel mixture offers significant increases in performance. Thanks to E85’s greater heat of vaporization compared to gasoline, it pulls more heat out of the intake charge as it changes state from a liquid to a gas. In other words, it requires more heat to vaporize than gasoline, resulting in reduced intake air temperature. This cooler, denser intake charge increases volumetric efficiency, which in turn boosts horsepower and torque. “E85 is like a cross between alcohol and gasoline,” Marvin Benoit of Quick Fuel Technology explains. “It has the same cooling effect as alcohol, but it’s not nearly as corrosive. It’s also much easier to fire up an engine that runs E85 because it lights off at a much lower temperature than methanol.” With the aforementioned octane rating of 110-116, E85’s superior knock resistance allows running a much higher compression ratio, further increasing performance. “If you have a nine-second bracket car, the enhanced cooling effect of E85 can knock off a half a tenth to a full tenth of a second in comparison to gasoline,” says Benoit. “Switching to E85 in and of itself doesn’t always increase horsepower, but it will increase torque. Even bigger gains are possible by increasing the compression ratio to take advantage of E85’s higher octane rating. You can safely run as high as 14.0:1 compression with E85.” E85 and Forced Induction Considering how well E85 performs in naturally aspirated engines, then it’s not surprising that forced induction applications can benefit even more. Even with relatively low static compression ratios of 8.5 to 9.5:1, supercharged and turbocharged motors are typically limited to 12-15 psi of boost on pump gas. In contrast, the combination of lower inlet air temperature and greater knock resistance allows racers to routinely push twice as much boost on E85 than on gasoline. And twice the boost equals twice the power. Understandably, figures this big may seem too good to be true, but the proof is in the dyno results. The boost experts at Steve Morris Engines know outrageously forced induction big-blocks better than anyone, and the performance they’ve managed to extract out of E85 is stunning to say the least. SME recently built 540 block-Chevy strapped with an F3-139 ProCharger that cranked out 2,500 horsepower at 30 psi on E85. Let that sink in for a minute. The same fuel capable of powering a 2,500hp doorslammer into the 6s can be had at your local gas pump for chump change. While some of the Federal subsidies that artificially lowered the price of E85 have expired, it’s still 30-40 cents per gallon cheaper than regular 87-octane pump gas. As this is being written in early 2016, that works out to less than $1.50 per gallon in most parts of the country, which compares quite favorably to the $8-$10 going rate for methanol, and the $15 or so per gallon price of admission for race fuel. “For a local bracket racer that wants an inexpensive race fuel, E85 is tough to beat,” adds Benoit. “Even when gas prices soar, E85 is still less than $3 per gallon.”

Switching To E85

As more and more racers have started singing the praises of E85 in recent years, the fear factor once associated with making the switch are quickly fading. First and foremost, there’s nothing to fear, as converting to E85 involves very few changes to the fuel system. Recalibrating any 4150- or 4500-style carburetor for E85 duty is as easy as swapping out the metering blocks and boosters, and replacing standard floats with corrosion-resistant sealed Nitrophyl units. Quick Fuel Technology offers convenient E85 conversion kits to take all the guesswork out of the process. For an even easier solution, QFT has also developed turnkey E85 carburetors. Although the richer stoichiometric air/fuel mixture of E85 does require moving a greater volume of fuel than gasoline, unless your current fuel pump is already near the limit, it can probably handle the extra fuel flow. “Methanol requires two and a half times the fuel volume as gasoline, but E85 required just 30-percent more flow,” Benoit explains.

Living With E85

Perhaps one of the biggest myths that scare people away from E85 are horror stories of rotting fuel lines and clogged up filters. In truth, these tall tales have been largely exaggerated by a combination of inexperience and hearsay. When adapting a fuel system for E85, a little bit of common sense goes a long way. “E85 is like an industrial cleaner,” says Benoit. “If you have an old fuel system that isn’t in good shape, E85 can wash out all the gas residue and dirt in the system and push it into the carburetor. That’s why it’s very important to clean out your fuel system very well before switching to E85. Rubber fuel lines work fine, but E85 shouldn’t be used with aluminum. We also recommend using a high-grade fuel filter and making sure that the foam in the fuel tank is compatible with E85. Taking these few simple precautions makes it very easy to adapt a fuel system to run reliably on E85.” In addition to the intake charge density and octane advantages of E85, it also offers bracket racers greater predictability as track conditions change throughout the day. “Due to the cooling effect of E85, changes in density altitude don’t affect engine performance nearly as much,” Benoit explains. “With gasoline, you’ll typically lose a hundredth of a second for each 150-ft increase in density altitude. With E85, that figure is more like 200- to 225 feet. That means fewer jet changes, and better round-to-round consistency.” For dual-purpose hot rods that will also see time on the street, E85 pays dividends on the open road as well. “On average, the coolant temperature on an engine running E85 will be 10-15 degrees cooler than a gasoline engine,” Benoit adds. “With the cooling effect and octane advantage, you could even run a race motor on the street.”
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