STOP Believing These E85 Myths and Learn the Facts

For years, E85 fuel has been a top choice for performance enthusiasts looking for a clean, affordable, and powerful alternative to race gas. But despite its mainstream acceptance, outdated rumors and myths continue to circulate, leading to confusion and, sometimes, tuning mistakes.

In this exclusive breakdown, we turn to Ryan Truax, a leading expert in flex fuel conversions, to definitively debunk the most persistent E85 myths and give you the clear facts you need to run your vehicle safely and reliably.

Busting the Top E85 Fuel Myths

Here are the facts that every enthusiast and daily driver needs to know about ethanol, fuel quality, and fuel system compatibility:

• Myth: Storing E85 will turn it into a gummy mess.
  • Fact: Pure ethanol does not "go bad" or leave behind residue. The gummy deposits people see in stored fuel systems are actually the leftover residue from bad gasoline that was blended with the ethanol at the pump. When the ethanol evaporates, it leaves behind the low-quality gasoline components.
• Myth: E85 is highly corrosive and will destroy your fuel lines and pump.
  • Fact: Modern fuel lines, including synthetic rubber and the superior PTFE material, are engineered to be ethanol-compliant. You won't damage your system immediately. However, if you have a 30-year-old vehicle, the original fuel lines and fuel pump may be due for an upgrade regardless of what fuel you run.
• Myth: Ethanol melts plastic fuel tanks.
  • Fact: This is an old rumor from the early days of E10, and it is entirely false for modern vehicles.
• Myth: A cheap water tester is accurate for measuring ethanol content.
  • Fact: Water testers are designed only to give a rough estimate (often inaccurate by up to 20%) for dealerships to void warranties. They provide false readings because other impurities in pump gasoline separate out, making the ethanol content appear much higher than it actually is. Never use a water tester for performance tuning.

The Unexpected "Friction" of E85 (and How to Fix It)

While E85 is a superior performance fuel, there are a few practical considerations, especially when converting an older vehicle:

• E85 is a Powerful Cleaner: Ethanol naturally cleans your fuel system. If your older vehicle has years of built-up debris in the fuel tank, the E85 will lift it all and push it toward your fuel filter. If converting an older car, be prepared to replace your fuel filter soon after converting.
• It Demands More from Your Fuel System: Because E85 has a lower energy density, your engine needs to flow more volume of fuel. This puts a higher, sustained load on your fuel pump. If your pump is already old (e.g., a 20-year-old C5 or C6 Corvette pump), the extra demand may cause it to fail.
• Cold Start Issues: High ethanol blends (E90+) can be difficult to start in cold weather because ethanol does not vaporize easily. This is why pump E85 has a blend of gasoline. If running a pure ethanol race fuel, adding a small amount of gasoline will fix any cold start issues.

The Critical Importance of Flex Fuel

Ryan Truax's experience has shown that running a dedicated E85-only tune on a street car is simply unsafe and impractical due to the wildly varying ethanol blends at the pump (which can range from 51% to 83%).

• Avoid the "Blend Guessing Game": Flex fuel technology, such as the ProFlex Commander, is the only reliable way for a street car to run E85. It uses an ethanol content sensor (ECS) to read the precise ethanol percentage in real-time and automatically adjust the tune.
• The Power of Automation: With a proper flex fuel system, you never have to worry about being stranded or risking engine damage. You can fill up with any blend of E85 and gasoline—or even pure gasoline—and the system will adjust immediately, giving you maximum power on E85 and maximum safety on low blends.
• Tuning for Peak Performance: While a ProFlex Commander will provide instant performance gains, a custom tune is still recommended to fine-tune aspects like ignition timing and cam timing, extracting every bit of safe, efficient power possible.

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