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Mazda Rx 7 Injectors
By: Jayson West
This is a generalized
write-up of information pertaining to the wide range of
injectors used on Mazda’s RX-7’s. This information will
hopefully come in handy for those looking for higher flow
injectors for cheap upgrades. I take no responsibility for any
errors in information, damages to your vehicle while performing
modifications, etc.
This list will be compiled
chronologically.
First Generation RX-7’s
1985 RX-7 GSL-SE
This car was the last year
of the first generation RX-7 body style (FB). This particular
trim featured a 135hp Fuel Injected 13B. All previous cars had
been carbureted. This car has two 680cc, low impedance,
Hitachi-type, square plug injectors. Originally they have a
black body, those this paint may be rusted away. Plastic tops
are Orange/Tan in color. The serial number on them is:
195500-0900.
Ways to spot this car:
Fuel injection manifold
with air cleaner assembly.
14 inch alloy wheels, in a
“phone-dial” pattern.
4x114mm bolt pattern. All
other FB’s have a rarer 4x110 bolt pattern.
Second Generation RX-7’s
The second generation of
the RX-7 was sold in the US from 1986-1991. They are commonly
identified as looking like 80’s Porsche 924/944’s. They were
offered in the US market in turbo and non-turbo charged models
in a coupe and convertible form. All US market convertibles are
non-turbocharged.
These cars are somewhat
divided by a mid design overhaul. Cars from 86-88 are called
Series 4 cars, or S4 for short. 89-91 cars are called Series
5’s, or S5. The difference between the two is somewhat
important, as you will read later. For now, let me list some
easily discernable differences between the two cars.
- S4 cars have black
colored body trim, S5 cars have body color trim.
- S4 cars have standard
manual seat belts, S5 cars have automatic/electric seat belts.
- S4 cars have squared
off, 4 block tail-lights. S5 cars have dark tail-lights with
three circles inside, resembling an 80’s Thunderbird or Nissan
Skyline.
Series 4 notes:
Naturally aspirated car’s
came with 460cc injectors. Turbo cars came with 550cc
injectors. All of them are a Hitachi type, square plug
injector. HOWEVER, 1986 and early 1987 cars came with LOW
IMPEDENCE injectors. Late (most) 1987 cars and all 1988 cars
came high impedance injectors. To easily discern the two,
refer to the VIN and build date. The switch over was made in
June of 1987. All cars with a VIN ending in 7601 and higher are
HIGH IMPEDANCE. All cars with a VIN lower than 7601 are LOW
IMPEDENCE. Another way to tell the difference is to remove the
stock airbox. For low impedance cars, there will be a resistor
box located under the airbox assembly.
Cliffs:
86-87 NA RX-7 w/ VIN
before an ending of 7601 = 460cc low impedance. (((I HAVE NEVER
SEEN ON OF THESE BEFORE IN REAL LIFE)))
87 Turbo RX-7 w/VIN before
an ending of 7601 = 550cc low impedance. Black body, tan
colored top. Serial # - (((I NEED TO LOOK THIS UP)))
87-88 NA RX-7 w/VIN of or
after 7601 = 460cc high impedance. Black body, red top. Serial
# - 195500-1350
87-88 Turbo RX-7 w/VIN of
or after 7601 = 550cc high impedance. Black body, red top.
Serial # - (((INSERT HERE LEX)))
Series 5 notes:
Again, NA cars came with
460cc injectors. Turbo cars came with 550cc injectors. All of
them are high impedance. HOWEVER, Mazda changed the wiring
harness (and the injectors) on the cars for the S5 upgrade. As
such, while these are still standard Hitachi-type injectors,
they do have an oval connection plug instead. To use them,
simply acquire new injector plugs (dealership, junkyard, etc.)
and solder them into your wiring harness.
These injectors all have a
silver, unpainted body. On the 460cc injectors, the tops are a
purple-red in color. The serial number is: 195500-2020. The
550cc injectors have a slightly more red top. It is best to
check they serial number to differentiate. That serial number
is: 195500-2010
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