Injector Size Calculator E85

Injector Size Formula for E85:

\[ Injector\_lbhr = \frac{(HP \times 0.7)}{(n\_injectors \times 0.8)} \]

Required Injector Size:

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1. What is the Injector Size Calculator for E85?

The Injector Size Calculator for E85 helps determine the appropriate fuel injector size needed for an engine running on E85 fuel, based on horsepower, number of injectors, and duty cycle.

2. How Does the Calculator Work?

The calculator uses the following equation:

\[ Injector\_lbhr = \frac{(HP \times 0.7)}{(n\_injectors \times duty\_cycle)} \]

Where:

\( HP \) — Engine horsepower
\( n\_injectors \) — Number of fuel injectors
\( duty\_cycle \) — Maximum injector duty cycle (typically 0.8 or 80%)
0.7 — BSFC (Brake Specific Fuel Consumption) factor for E85

Explanation: The equation calculates the required fuel injector flow rate in pounds per hour (lb/hr) to properly support the engine's power output when running on E85 fuel.

3. Importance of Proper Injector Sizing

Details: Correct injector sizing is crucial for engine performance and reliability. Undersized injectors can lead to lean conditions and engine damage, while oversized injectors can cause poor idle quality and drivability issues.

4. Using the Calculator

Tips: Enter your engine's horsepower, number of injectors, and desired maximum duty cycle (typically 0.8 for 80%). All values must be valid (HP > 0, injector count ≥1, duty cycle between 0.1-1.0).

5. Frequently Asked Questions (FAQ)

Q1: Why is the BSFC factor 0.7 for E85?
A: E85 requires about 30% more fuel flow than gasoline due to its lower energy content, hence the higher BSFC factor.

Q2: What's a typical duty cycle for injectors?
A: Most tuners recommend not exceeding 80% duty cycle (0.8) for reliable operation and headroom.

Q3: How does this differ from gasoline injector sizing?
A: Gasoline calculations typically use a BSFC of 0.5-0.6. E85 requires larger injectors due to its different stoichiometric requirements.

Q4: Should I round up my injector size?
A: Yes, it's generally recommended to round up to the nearest available injector size for safety margin.

Q5: What if I have staged injection?
A: For staged injection systems, calculate primary injectors for normal operation and secondary injectors for high boost/rpm conditions separately.