Muscle Mustangs & Fast FordsHow To Engine
E85 Fuel Conversion
Alternative fuel-the way to go!
Renewable energy sources—it was once the hottest topic in the media when gasoline prices were soaring uncontrollably, and politicians weren't worrying about the falling economy. The price-per-gallon peaked in mid-2008, further motivating the need for an alternative fuel at the time, and the popularity of ethanol-based fuels increased.
Ethanol (also known as alcohol) certainly isn't a newly developed blend of fuel, since it goes back to the 1850s as a lighting fuel, but taxes placed on it during the Civil War made way for the popularity of kerosene as a replacement. It re-emerged in the early 1900s when the taxes were lifted, and a few years later, Henry Ford even used a mixture of gasoline and ethanol to power his first Model A car in 1908. Prohibition would slow ethanol use in the '20s only to see it come back in the '40s for World World II. After the war, the alternative fuel went quiet until the gas crisis of the '70s.
The recent rise in E85 popularity, which consists of 85 percent ethanol and 15 percent gasoline, came about due to ethanol's ease of production using common ingredients like corn. Unlike oil in the ground, the E85 fuel is created from a renewable energy source. The hope was that its use could cut down the need for 100- percent petroleum-based gasoline—and specifically, foreign-supplied oil.
There are some drawbacks to E85. The vehicle has to be capable of utilizing such a fuel including a special tune-up and proper fuel delivery equipment to withstand the corrosion effects, and extra volume required to maintain proper a/f ratios. The market responded with Flex-Fuel models, of which there are over four million flexible fuel cars and SUVs on the road today!
Naturally, when the economy tanked in the second half of 2008 so did the price per gallon of gasoline. Couple the falling price of gas with the expiring tax credits on E85, and its popularity has cooled considerably in the past three years.
E85 might not be the media darling it once was, but that doesn't mean the fuel has gone away. There are more stations expanding their offerings, and right now 41 of 51 regions in the United States sell ethanol-based fuel. So what does that mean for your Mustang or Ford?
For our market, the use of E85 is increasing as many enthusiasts have recognized its performance advantage over pump gas. This is mainly due to the high octane rating, which helps resist detonation, so you can safely run more compression, boost, and ignition timing advance. This is where our story begins, as we look to increase performance in a supercharged Two-Valve modular engine.
The wonders of E85 for the mainstream have provided our segment with a high-octane fuel—it ranges between 100 and 105 octane, right out of the pump and at affordable pricing. As of this writing, the author purchased E85 fuel for $3.69 per gallon in the greater New York City area. The national average price of E85 (at print time) is $2.88 per gallon as compared to $3.13 per gallon of 87-octane gasoline.
We aren't here to talk about how much you are going to save at the pump, because the one downside to E85 is that more volume is needed to feed your engine. This is because burning ethanol produces less energy per volume than gasoline.
We've heard reports of mpg decreases of anywhere from 20 percent to 30 percent, but in our application we are chasing more horsepower so the decrease in mpg isn't of any concern. The fact that did concern us was that the engine requires a significant amount more fuel under wide-open throttle. This was going to tax the fuel system, and we had to verify our Mustang was up to snuff. We turned to Dez Racing where Mike Dezotell evaluated our test car to see what was needed to go from a gasoline to an alcohol-guzzling hot rod.
The test vehicle is an '01 GT with a mildly built 284ci short-block that is topped with Trick Flow 38cc Twisted Wedge 4.6L cylinder heads, Trick Flow intake, TFS Stage II camshafts, and a ProCharger P1SC-2 intercooled supercharger. On gasoline, it cranked 616 rwhp and 485 lb-ft of torque, sans methanol injection.
The Mustang is equipped with an in-tank hat that carries two fuel pumps (255-lph each). At the same time, Dez Racing also set the car up with AN-8 fuel line on the feed side and a return size line of AN-6 while a set of 1/2-inch fuel rails sit on the Trick Flow manifold. A set of eight Ford Racing 80-lb/hr fuel injectors deliver the fuel, while an Aeromotive regulator maintains proper pressure.
Dezotell felt that this engine would be making over 650 rwhp with the added timing and you would have to actually size the system as if it was making 30 percent more than a gasoline setup. The fuel pumps are both rated at 255-lph, but have quite a bit of street miles logged since being installed. Couple that with a fuel line size that is questionable, and we were looking at an upgrade in pumps and fuel lines.
A general rule of thumb is an AN-8 feed and AN-6 return line are good to around 750-800 rwhp in gasoline applications and 600-650 rwhp when combined with E85. These are estimates because it also depends on the transmission type along with power adder efficiency. A turbo setup tends to get away with a little more, while a supercharged combination has to factor in power to turn the blower. We were on the cusp of that range with this ProCharger-blown Two-Valve, so Dezotell decided to call Lethal Performance for added insurance.
Lethal Performance recently released its DivisionX fuel hats and our test car runs an '03 Cobra gas tank so we ordered the appropriate hat—Lethal/DivisionX covers just about every Mustang model from the '96 Mustang GT through the current Shelby GT500. Jared Rosen of Lethal prescribed the company's Stryker fuel pumps, two of them to be exact, and each pump cranks out 340 lph at a 40 psi of fuel pressure.
Rosen told us the pumps are also compatible with E85 fuel, which is an important factor. Verify with the manufacturer of your fuel lines and fuel pump to ensure the move to E85 is possible. Rosen also sent along AN-10 feed and AN-8 return line to replace the smaller lines on the car. The DivisionX fuel hat is designed to run the large lines, as well as the smaller AN-8 feed and AN-6 return setup for lower volume requirements.
On the tuning side, Dez fired up the SCT software and changed the stoichometric number from gasoline's 14.7:1 to the E85 rating of 9.76:1. There is a pull down menu to adjust this ratio. Another change was to increase base fuel pressure (a total of 28 percent) from 40 psi with gasoline to 55 psi with the E85. An easy check-out pass on the dyno showed the fuel injectors were already near 100-percent duty cycle with the fuel pressure at 40 psi, so the combo really needed larger injectors. Since we didn't have them, we increased pressure for the purpose of the test. Leaving timing the same we saw the baseline of 616 rwhp increase to 635 rwhp—a gain of 19 rwhp with no other changes except the extra fuel. "The reason for the increase in power is the greater oxygen content of the E85 compared to pump gasoline," says Dezotell.
One of the reasons for running your car on E85 is the benefit of the increased octane rating, thus allowing more boost, more compression, and more timing over pump-gas applications. Increasing the compression ratio was out of the question since the engine was in the car already. Dezotell shied away from adding more boost because the P1SC-2 was at maximum impeller speed (60,000 rpm) thanks to a 3.20-inch blower pulley and a 6.60-inch crank pulley (impeller speed = crank pulley size/blower pulley size x step-up ratio x max engine rpm).
The boost gauge on the DynoJet chassis dyno shows a peak of 16 psi at the 7,100-rpm redline. It left Dezotell with only one option and that was increasing the ignition timing, and he did so conservatively with an extra 3 degrees throughout the entire curve. That put total timing at 22 degrees at the peak of 7,100 rpm.
The Two-Valve screamed with the extra 3 degrees as it worked its way up to redline, and when the pull was complete, the results were outstanding—669 rwhp and 519 lb-ft of torque. The E85 fuel allowed timing to be increased by 3 degrees, which resulted in gains of 53 rwhp and 34 lb-ft of torque. "I think there is more power in there," Dezotell comments, "but for now we're happy."
E85 is a power enabler allowing more cylinder pressure and/or more timing as if the engine was running on race fuel, but it cost us $3.69 per galloon as compared to $12-$17 per gallon for a quality high-octane race fuel. Make the switch to more power for less money—being greener is an added bonus.