What size injectors do I need?

Many people believe that the size of fuel injectors are based on their physical dimensions. This is a common misconception. Their sizes are actually based on the flow rate.

Flow rate is a measure of the fuel injected by the fuel injector over time. It is measured in pounds per hour (lbs/hr) or cubic centimeters per minute (cc/min). It is important to use the correct flow rate for your engine as it achieves the proper fuel to air ratio.

Flow rate describes the amount of fuel that an injector can flow at a certain pressure for a certain amount of time. It is determined by a variety of factors, including the physical size of the injector. Engines require specific injector flows during different operating phases. The engine manufacturer determines these specific flow rates. Next, the manufacturer programs the flow into the electronic control unit (ECU). The ECU uses these values ​​to determine the number of pulses that need to be sent to each injector to achieve the desired level of fuel delivery.

Follow these simple steps to choose the right size injector for your engine.

Step 1: Determine Target Horsepower

How much power do you actually expect from the engine? You can find a realistic estimate by adding the expected horsepower gain from additional modifications to the stock engine horsepower.

Step 2: Calculate the specific fuel consumption for braking

Brake specific fuel consumption (BSFC) is the ratio of the amount of fuel consumed to the amount of power output. This will vary depending on the type of fuel used and the amount of air intake the engine is taking. You can calculate your engine's BSFC, or use fuel type and air intake to get an estimate.

Step 3: Find the safe duty cycle of the motor

The safe duty cycle is the percentage of time the injector is open during the cycle. Most stock engines should use 80% of the safe duty cycle, and performance modified engines can run at 85-90% of speed.

Step 4: Calculate the Ideal Injector Size

Now that the target horsepower, BSFC, and safe operating cycle have been found, the ideal injector size can be calculated. Use the following formula to calculate the correct flow rate for your injector.

Injector flow rate = (horsepower × BSFC) / (number of cylinders × duty cycle)

To find the ideal flow rate, simply plug the values ​​found in steps one, two, and three into the formula and solve.

The result will be flow rate in pounds per hour. To get results in cc/min units, use the lb/hr to cc/min conversion calculator.

What you need to pay attention to is that the size of the fuel injector hole has a great impact on the fuel consumption of the car.

Generally speaking, the larger the nozzle hole diameter, the flow rate will increase accordingly. This is because there is a direct proportional relationship between the flow rate of the nozzle and the hole diameter. Larger holes provide larger channels for fluid to pass through more easily, thus increasing flow. The size of the injector hole is an important parameter in the automobile fuel system, which determines the amount of fuel injected, the injection pattern and the combustion efficiency. If the hole size of the fuel injector is not appropriate, it will affect the normal operation of the engine and thus affect the vehicle's fuel consumption.

If the hole diameter of the fuel injector is too large and the amount of fuel injected is too much, combustion will be incomplete, and part of the fuel will be discharged without burning, causing the car's fuel consumption to be too high. If the injector hole diameter is too small and the fuel injection amount is too small, the engine will lack power, the fuel combustion will be incomplete, and the car's fuel consumption will be too high.

Providing the right amount of fuel to your engine is critical to maximizing engine performance and optimizing the benefits of other performance improvements. Therefore, obtaining a fuel injector of appropriate size is an important step when adjusting vehicle performance. A fuel injector of appropriate size can make the engine fuel injection amount appropriate and complete combustion, thereby reducing vehicle fuel consumption and improving vehicle fuel economy.

INAT has focused on high-end auto parts for car upgrades over 10 years, and has strong technology and perfect development capabilities. INAT provides car fuel injectors, including 650cc car fuel injectors, 750cc car fuel injectors, which can effectively improve fuel efficiency, reduce fuel consumption, and upgrade your car's power.

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