Fuel Injector Clinic has been our go to brand for injectors of all sizes for the past 4 years. Having used nearly every available brand of high flow injectors on the market for Subaru, only FIC injectors have provided consistent quality, reliability, and performance across every size and every set we've used. Unlike the competition FIC's largest injectors still retain excellent fuel atomization for smooth drivability and are closely matched at low pulse widths to avoid idle misfire issues.
Sold in sets of 4. Supplied with plug & play adapters for no additional charge!
1000cc, 1200cc, 1440cc, and 1650cc sizes usually ship the next business day. Others usually ship within 1 week.
How do I determine what injector size I need? A rough approximation of an engine's fuel requirements can be determined based on the horsepower. Start with a realistic approximation of the expected power output (crankshaft HP). Multiply HP by 0.5 for normally aspirated engines or 0.6 for turbo engines. If running E85 use 0.65 for normally aspirated and 0.77 for turbo. This multiplier is an approximation of the brake specific fuel consumption and its entirely possible the actual number may be different depending on the efficiency of the engine but these numbers will get you in the ballpark. Take the resulting number and divide by the number of injectors multiplied by 0.80 (or maximum duty cycle). This will give the injector flow requirements in lbs/hr. To convert to cc/min multiply by 10.5. For example, a turbocharged 4 cylinder engine (with 4 injectors) running E85 and producing 600bhp would look as follows: (600 x 0.77)/(4 x 0.8) = 144.38 lbs/hr x 10.5 = 1516cc/min. Therefore a ID1700 would be the best option.
Can I raise the base fuel pressure in order to run a smaller injector? Raising the fuel pressure will increase the flow through the injectors. The percentage increase in flow will be equal to the square root of the new pressure divided by the old pressure. For example, increasing fuel pressure from 43.5psi to 50psi will increase flow through 1000cc injectors to 1072cc.
Will idle quality and drivability be compromised with a larger injector? FIC's data match technology closely matches the injector flow at very short pulse widths which ensures proper air-fuel ratios in each cylinder. Large injectors tend to have greater variability in the short pulse width range so competitors products may suffer from variations in individual cylinder air fuel ratios that are significant enough to cause a cylinder roughness condition. This condition will be less of an issue when running E85 due to the higher fuel volume requirements when compared to normal pump gas. Additionally, some lesser quality injectors may provide poor fuel atomization in their large injector sizes and therefore will suffer from poorer drivability under light throttle or sudden throttle changes.
That being said even FIC injectors will not drive quite as smoothly when running larger injector sizes compared to the smaller sizes.
