E85 Vs. Gasoline: Dynos & Performance

Installing an eFlexFuel kit and running E85 delivers real, repeatable horsepower and torque gains on every engine—stock or modified, NA, supercharged, or turbo. These gains come from E85’s chemistry, not from ECU tuning. Learn the science behind how and why all builds make more power with eFlexFuel + E85 below, without touching the vehicle’s ECU.

At a Glance: E85 Vs. Gasoline Performance

*Effective Octane exceeds 115 due to charge cooling synergies.

Why eFlexFuel + E85 Outperforms Gasoline—For All Builds

1. Knock Resistance: Maximum Timing, Maximum Power

• E85’s high chemical octane (96-100 AKI / 100–105 RON) and charge cooling mean knock is virtually eliminated.
• Effective octane exceeds 115 due to charge cooling synergies.
• Unlike gasoline, which often forces your ECU to pull timing to prevent knock, E85 allows your ECU to run at its maximum safe ignition advance—even at peak cylinder pressures, unleashing the engine’s full power potential.
• Result: More power across the entire RPM range, without touching your ECU or tuning

2. Charge Cooling: Denser, Cooler Intake Charge

• Ethanol absorbs 2.4x more heat than gasoline during vaporization (841 kJ/kg vs. 350 kJ/kg).
• Intake Air Temperatures drop by 15–30°F (8–16°C)**, increasing air density by 4-7%.
• Cooler, denser air means more oxygen per cylinder, supporting bigger, more consistent power—especially under load or repeated pulls.
• Result: Smoother, more responsive power delivery at all throttle positions.

3. Faster Flame Propagation: Harder, Quicker Power Strokes

• 4.2 m/s flame speed vs. gasoline’s 3.5 m/s. Ethanol ignites and burns faster than gasoline, with less delay from spark to combustion and a quicker-moving flame front.
• 12% quicker pressure rise in cylinders, translating to sharper power strokes.
• 5% shorter combustion duration maximizes energy extraction.
• Result: A sharper, more efficient pressure rise in the cylinder, translating to more usable torque and horsepower throughout the rev range with improved throttle response.

4. Oxygen Content: Cleaner, More Complete Combustion

• E85 is ~30% oxygen by weight vs. gasoline’s 0–3.5%.
• This high oxygen content means more fuel and air can be burned in each cycle, leading to more complete combustion and more power.
• Result: Improvement for all combustion conditions.

**Actual IAT drop depends on measurement location and engine setup. Most IAT sensors measure air temperature before fuel is injected, so the full cooling effect of E85 is not always reflected in measured IAT. The real benefit occurs in the intake manifold and combustion chamber after fuel vaporization

How eFlexFuel Kits Make It Happen—No Tuning, No ECU Changes

• eFlexFuel kits do not touch your ECU or alter timing/boost. eFlex kits simply deliver the correct amount of fuel for any ethanol blend, allowing your engine to take full advantage of E85’s properties while keeping all OEM safety and emissions systems intact.
• Dyno-proven gains: All increases are achieved with factory timing and boost—no tuning, no map changes, just proper fueling for E85.
• Seamless operation: Fill up with E85, gas, or any blend—eFlexFuel instantly adapts, so you get consistent gains and drivability

Summing It Up: eFlexFuel + E85 Performance Gains Vs Gas

eFlexFuel kits allow your vehicle to take advantage of E85’s higher octane, greater oxygen content, superior charge cooling, and faster burn speed to make more power and torque on every engine, at every RPM—no tuning or ECU changes required.

• Stock or modified, NA or forced induction, you’ll see gains across in the powerband, not just peak.
• Knock resistance means your ECU keeps timing advanced, maximizing safe power.
• eFlexFuel delivers these benefits automatically, with factory reliability and safety

Understanging Dyno Results

What are Peak Gains Vs Max Gains and which one matters more?

You’ll notice we reference both Peak Gains and Max Gains (AKA Curve Gains) in our dyno results. Both measure the performance difference between runs, just in a different area:

Peak Gain is the difference in horsepower at the HP peak of each run, or the highest measured HP. This is the peak HP number from the run.

Max Gain/Curve Gain is the largest observed difference in HP between the two runs, or the greatest increase in HP at any point. This usually takes place under the curve, which is why some refer to this measurement as “curve gains.”

Max Gains/Curve Gains typically better reflect the “seat-of-the-pants” performance increase you feel because it’s where you spend time driving, under the curve and inside the powerband. Peak gains, on the other hand, are just a momentary peak in performance, often at redline.