All stock FC3S turbo fuel injectors are rated at 550cc/min. Kouki FC3S
all ran high-impedence fuel injectors; these fuel injectors have an red tops
with oval plugs. These Kouki high-impedence fuel injectors plastic tops
normally turn pink due to heat and age.
The Zenki FC3S had mixed low-impedence and high-impedence fuel injectors
depending on build dates or VIN's. The split was made with FC3S with
build dates before or after June 1987 (6/87), and last four digits in VIN at
...7601. Zenki FC3S up to this build date and VIN split all used
low-impedence, purple-top fuel injectors; the low-impedence fuel injectors
turn brown/tan with heat and age. Zenki FC3S after this build date and
after this VIN split used high-impedence, red-top fuel injectors; these
high-impedence fuel injectors turn pink with heat and age. The Zenki
FC3S used rectangle plugs that were not compatible with the Kouki
FC3S engine harness. "Low-impedence" fuel injectors typically
measure about 2Ω. "High-impedence" fuel injectors typically
measure about 14Ω.
use low-impedence fuel injectors in a car originally designed to use
high-impedence fuel injectors by running some 20-watt, 10Ω resistors.
You can use high-impedence fuel injectors in a car originally designed to use
low-impedence fuel injectors by jumping the fuel injectors resistor block
located at the front, passenger side of the engine bay.
You can use fuel
injectors from a 1984-1985 RX-7 GSL-SE. These are rated at
680cc/min. Note, the GSL-SE only uses two of these fuel injectors, so if
you want 4, you need to find another set. These are low-impedence fuel
injectors. There are also 720cc/min fuel injectors that are sold by GReddy
for $130 each. These are also low-impedence fuel injectors. All the
above mentioned fuel injectors are drop-in replacements. You can run other
types of fuel injectors, but they will need some modification to fit properly.
Keep in mind, the stock fuel injectors (4 × 550) can sustain about 250bhp
at the flywheel under stock fuel pressure (35psi). 4 × 720 will support
a little over 300bhp at the flywheel at stock fuel pressure.
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