Nozzle Types
There are essentially 3 different types of nozzles:
Pintle
This is the most common type and still the best. A tapered needle sits on a tapered seat. When the solenoid is energized, the core and needle is pulled back, allowing the fuel to discharge. This design has been well proven for over 30 years.
Bosch Disc
Lucas Disc
The Bosch disc type uses the same type of actuation mechanism as the pintle type but replaces the pintle with a flat disc and a plate with tiny holes. These work fine with a good spray pattern but are slightly more prone to deposits plugging the holes. The Lucas type buries the disc up inside the body to reduce the mass of the assembly for quicker response. The Lucas types typically have a very narrow spray pattern which can affect idle and throttle response in some cases.
Rochester Ball
The Rochester division of GM makes the ball type injector for OE applications as well as the larger flow race types for MSD. These use a ball and socket arrangement. These have excellent atomization and a wide spray pattern but are also prone to partial plugging by varnish deposits.
Side Feed injectors do not interchange with top feed injectors. Subaru, Nissan, Ford & some Mazda have used these type injectors.
RX-7 stock injectors
1984-85 RX-7 195500-0900 Peak and Hold 680cc Orange Top
1986-87 RX-7 195500-1350 Peak and Hold 460cc Red Top
1986-87 RX-7 195500-1370 Peak and Hold 550cc Tan Top
1988 RX-7 195500-1350 Saturated 460cc Purple Top
1988 RX-7 195500-1370 Saturated 550cc Purple Top
1989-91 RX-7 195500-2010 Saturated 460cc Red Top
1989-91 RX-7 195500-2020 Saturated 550cc Purple Top
1993-up RX-7 Twin-Turbo Saturated Primary 550cc Secondary 850cc