Grams Performance Fuel Injectors & Rails

Grams Performance Fuel Injectors & Rails

Grams Performance is a manufacturer of precision high-flow fuel injectors, fuel rails, and fuel system components designed for the serious performance and motorsport market where accurate, consistent fuel delivery at elevated flow rates is required for reliable high-power operation. The brand's injectors are manufactured to tighter flow matching tolerances than many competitors, with matched sets calibrated within 1 to 2 percent of each other to ensure cylinder-to-cylinder fuel distribution consistency that is critical for producing a smooth, drivable tune on modified engines. Grams covers popular import and domestic performance platforms including the Honda K-series and B-series, Subaru EJ, Mitsubishi 4B11T, Nissan RB and SR, and Toyota 2JZ, as well as GM LS and LT applications where high-flow injectors are needed to support supercharged and turbocharged power levels. The complete Grams fuel system catalog includes high-flow rails, fuel pressure regulators, and fittings to build a clean, high-reliability fuel system alongside the injectors.

Popular Upgrades

Grams 1000cc, 1300cc, and 2150cc injectors are the most popular flow rates for forced induction builds targeting 400 to 700 horsepower, with the correct injector size determined by the engine's target power level, fuel type, and injector duty cycle at maximum power. Grams billet fuel rails for the Honda K20 and K24, Subaru EJ engine, and GM LS series are machined from 6061-T6 aluminum and provide a cleaner high-flow fuel delivery path than the factory stamped steel or plastic rails. Grams fuel pressure regulators allow fine adjustment of system fuel pressure to accommodate E85 conversion requirements or high-boost fuel demand that exceeds the factory regulator's delivery capacity. Return-style fuel system conversion kits from Grams address the common performance limitation of returnless factory fuel systems on modern EFI applications.

Performance and Handling

Selecting the correct injector size is a balance between flow capacity and injector minimum pulse width, as oversized injectors can make a tune difficult to control at idle and light throttle because the minimum fuel delivery per cycle exceeds the engine's needs. A general rule is to size injectors for 80 percent duty cycle at maximum power, leaving 20 percent headroom for rich conditions and fuel pressure variations. Grams injector data sheets provide the firing frequency correction factors and deadtime values required for accurate ECU tuning, and using this calibration data during the tune process is essential for achieving accurate fuel delivery across the entire RPM and load range.

How do I choose the right injector size for my build?

Injector sizing is calculated using the formula: injector size in cc equals (horsepower times BSFC) divided by (number of cylinders times 0.80). For a 400-horsepower turbocharged four-cylinder running gasoline with a BSFC of 0.55, this calculation yields approximately 344cc per injector at 80 percent duty cycle, making a 370cc or 440cc injector appropriate for this application. For E85 conversions, multiply the calculated value by 1.3 to 1.4 to account for E85's lower energy density and higher required fuel volume at the same power level.

Do Grams injectors come with calibration data?

Yes, Grams Performance provides injector characterization data sheets with every injector set, including deadtime values at multiple battery voltages, short pulse width adder tables, and the flow rate at various fuel pressures. This data is formatted for common ECU platforms including AEM Infinity, Haltech, MoTeC, and Hondata, making it straightforward to enter the correct injector calibration without requiring expensive injector characterization testing at a fuel lab. Using the provided calibration data significantly reduces the tuner's time required to achieve a clean idle and precise fuel delivery across the operating range.

Why These Parts Fit Right

Every Grams Performance injector and fuel system component in this collection is designed and flow-matched to the specific engine application for direct-fit installation and accurate calibration. Fast shipping delivers your fuel system upgrade components quickly. Expert support is available to confirm the correct injector size and fuel system configuration for your specific engine and power target.

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