Universal, any electronic fuel injected engine with a return style fuel system with port or throttle body injection. May be used with direct injection vehicles to regulate fuel pressure to the inlet of the high pressure fuel pump. May be used for inline or deadhead regulation. May be used in a series with another F1i, F2i, or F4i to supply multiple pressures and/or reference strategies with one feed line. Pressure Ports: two ORB-8 female (fitting not included). Return Port: ORB-8 female (fitting not included). Auxiliary Port: NPT 1/8 female (plug included, PTFE thread sealant required). MAP Reference Ports: two NPT 1/8 female (fittings not included). Base Pressure range: 25-70 psi. Boost Limit: 250 psi. FKM/Nomex composite diaphragm is compatible with gasoline, race gas, ethanol, methanol. MTBE will reduce diaphragm life. Not compatible with acetone or brake parts cleaner. Hydrodynamic internal cavity suitable for passthrough regulation. Zero chatter design for maximum life expectancy and maintained accuracy. Fine Pitch adjustment screw for precise setting of fuel pressure. Reversible stainless steel mounting bracket included. What are the key differences and similarities between the F1i and F2i? F1i and F2i have exact same valve geometry and performance specifications. F2i has a ceramic/stainless valve, F1i has stainless/stainless valve. F2i has a corrosion resistant fluoropolymer coated spring.