Z31 300ZX Performance fuel options:

Something I think lots of people skip right over is getting the most out of your stock fuel system before upgrading to something "bigger" and hence, much more expensive. The 88-89 ECCS is virtually limitless in its potential, the devices attached to it are not. The stock fuel injectors on a 84-89 Z31 Turbo have a flow rate of about 260CC/min. This means at maximum duty cycle and stock (37psi) fuel pressure they will actually put out less than 260cc's of fuel in one minute. However the stock ECU limits the injectors duty cycle to around .80 or 80% duty cycle. In addition, injectors are rated at maximum flow (with the pintle fully open) meaning they never reach this level of flow in operation. This means on an entirely stock fuel system (and stock engine) you will have AT MOST ~300HP at the crank (and probably running lean up top), and at that point you will also be maxing out the stock T3 turbocharger as well. A very detailed bit of information on fuel injectors is right here. The stock Mass Airflow Meter (AFM, MAF, etc) also cannot meter very much air, greatly limiting tuning resolution with higher boost levels.

You will need to upgrade your fuel pump before going much further. The stock Z31 fuel pump (same for NA and Turbo applications) will have trouble keeping up fuel flow at anything over ~300 crank HP. A Z32 TT unit or Walbro 255lph for a 240SX will work and supply ample fuel for 500HP. Also, if you plan to run higher fuel pressure, be aware that fuel flow decreases as required pressure increases (info here). If you read that article you will notice fuel pumps gain a substantial ammount of flow and pressure potential from additional voltage over 12V. There are devices on the market for increasing fuel pump voltage with boost pressure (IE the "Boost-A-Pump"); however these would be a waste of money for your 300ZX because the factory ECCS already has this feature built in!

You can install larger injectors, but you need a way to control your fueling and ignition timing.

As I see it, there are quite a few options in the fuel upgrade arena for a Z31 300ZX including:

So, which one is best? I bolded what are considered the most "cost effective" solutions. A standlone, NIStune, megasquirt or "home" modification of the stock 88-89 Nissan ECCS. All three have very few compromises and offer flexability to tune your fuel, timing and airflow to your hearts content.

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