So you’re looking to upgrade the injectors on your Nissan 300zx Twin Turbo? It’s a common modification for those seeking more power, and understanding the nuances is key to a successful upgrade. Let’s dive into what you need to consider when thinking about swapping out your 300ZX Twin Turbo injectors, especially if you’ve heard about using R33 injectors.
Understanding 300ZX Injector Types
The Nissan 300ZX, particularly the earlier models, utilizes side feed injectors manufactured by JECS. There are generally two styles: early and late. Early Z32s typically came with a square plug connector, while later models transitioned to a square oval shape. It’s important to identify which type your 300ZX Twin Turbo has.
- Early NA (Naturally Aspirated) 300ZX: These models often feature red square top side feed injectors, rated at 270cc.
- Early TT (Twin Turbo) 300ZX: The 300ZX Twin Turbo from the early years is equipped with purple square top side feed injectors, delivering 370cc. These can sometimes change color to a chocolate brown due to heat and age, but remain the same specification.
Later specification 300ZX models also use 370cc injectors with the same color coding, but they are not a direct drop-in replacement for the earlier style and would require an adapter kit for installation.
R33 Injectors and Your 300ZX Twin Turbo
The Nissan Skyline R33, in some variants, also utilized late-style 370cc side feed injectors, similar to the later 300ZX models. This is where the idea of R33 injector compatibility comes from. However, some R33 models, particularly the GTR, and the R34 generation cars, used top feed 440cc injectors. These top feed injectors are significantly more complex to fit into a 300ZX Twin Turbo that originally used side feed injectors, requiring substantial modification.
If you are considering R33 injectors for your 300ZX Twin Turbo, it’s likely you are looking at the 555cc injectors that were used in some performance-oriented R33 and other Nissan/Subaru vehicles with square oval side feed configuration. While physically fitting these might be possible, it’s crucial to understand the next critical step.
The Necessity of ECU Tuning After Injector Upgrade
Any change in injector size on your 300ZX Twin Turbo mandates a recalibration of your Engine Control Unit (ECU). Simply installing larger injectors like 555cc R33 injectors without adjusting the fuel mapping will result in an overly rich fuel mixture, leading to poor performance and potential engine damage.
To manage the increased fuel flow from larger injectors, you will need to retune your ECU. Options for ECU tuning on the 300ZX Twin Turbo include:
- Chipped ECU with Off-the-Shelf EPROM: This involves replacing the chip in your factory ECU with a pre-programmed chip (EPROM). While simpler, customizability is limited.
- Custom ECU Remapping (Nistune Recommended): For optimal results, custom remapping is highly recommended. Using a Nistune board, which can be installed into your stock ECU, makes finding a tuner significantly easier. Nistune allows for real-time tuning and precise adjustments to your fuel and ignition maps to properly accommodate the new 555cc injectors and any other modifications you might have.
In conclusion, while R33 injectors, especially 555cc variants, can be considered for a 300ZX Twin Turbo upgrade, it is not a straightforward swap. You must identify your injector type, understand the R33 injector specifications, and, most importantly, ensure you get a proper ECU tune, ideally with a Nistune setup, to safely and effectively utilize the larger injectors and maximize the performance of your 300ZX Twin Turbo.
