Thanks for buying a set of Flow Force Injectors! There are only a few things that stand between you and the power and performance of EV14 awesomeness. If any of these steps are confusing, or if you run into issues, please email me at team at goflowforce dot com so I can help, and so I can improve this documentation for others.

Note: if you purchased FF640 injectors in early 2019 and your flow rate card says they flow around 110cc, it’s not true. Please email Nigel at the address above for your actual flow rates. #excelfail

If you are the type to wait for the movie to come out rather than reading the book, some customers have created some top-notch videos on youtube. Check out the videos by supercarmio, OGPedXing, and Beavis Motorsport. If you see any other great videos, or if you made one yourself please let me know so I can add it to this list.

Assembly

The following are instructions for a 640cc kit for a 1990-2005 Mazda Miata. Other kits are largely similar.

What's included

1. 4x EV14 injectors
2. 4x Bottom cushions
3. 4x Blue top hat fuel rail adapters
4. 4x Top hat o-rings
5. 4x Connectors
6. 3x Fuel rail spacers (yes, 3. FF640 only)
7. 1x Dielectric grease
8. 4x Fuel filters (not pictured)
9. 4x Grey bottom cup adapters (FF740, FF900, and FF960 only)

To assemble the injector kit, take the bottom cushion (2) and slide it on to the injector on the end the fuel sprays out. Take a small amount of dielectric grease and apply it to the blue o-ring at the top of the injector, and the included top hat o-rings (4). Slide the top hat o-ring over the top of the top hat and into the machined groove. Drop a fuel filter, basket side first, into the top of the top hat. The bore hole has a taper to it, so the filter will rest somewhere between the very top and half way in. Slide the top hat over the top of the injector. Now, your fancy new injector should have the same basic dimensions as your stock injector. If that isn't the case, something has gone horribly wrong.

Note on the 380cc kit_ The filter comes pre-installed in the injector. If you need to remove it, you can do so with a jewelry screwdriver. There are no adapters, although there are spacers. These kits also come with two sets of o-rings. The reason for that is that it’s really easy to pinch them, so I’ve sent some spares. More on that later.

Note on the 740, 900, and 960cc kits_ The grey cup adapter goes on the tip of the injector and the blue adapter goes on the top. The bottom cushion goes on the grey adapter. There are no fuel rail spacers.

Note on NC kits - you don’t get buttom cushions or electrical connectors. On the FF640-NC kit, the grey cup takes a green o-ring.

Installation

Follow the instructions in your shop manual to install these injectors. Once they have been assembled, just treat the rest of the process like you would with stock injectors. Be extra careful when you remove your fuel rail. The black plastic isolators are really easy to lose, and you need them for re-assembly. Pop a fuel rail spacer on each one.  Also, with all kits, but especially the 380cc kit, if you put the injector in the rail at an angle, or without grease, it’s possible to pinch the o-ring and cause a leak. Be super careful, and use a dab of the dielectric grease on the o-ring to help it slide in place.

When it comes to the connectors, if your car is older and/or higher mileage, there is probably some fretting corrosion in the connector, and you should clean the contacts on the female plugs on your wiring harness. There are various methods to do this, either mechanical (sticking something in there to scrape off any corrosion) or chemical (spray some contact cleaner in there). Either method is fine. Before plugging anything back in, apply a small amount of dielectric grease to both cavities of the female plugs on the included connectors, and on your wiring harness.

Tuning

A programmable or standalone ECU such as Megasquirt (MS2/MS3), Haltech, AEM EMS, or ME221/ME442 is required to run these injectors. Tuning injectors correctly is critical to drivability, so we strongly recommend having an experienced tuner handle this setup. If you’re confident in your tuning abilities—read on.

Simply adjusting required fuel and dead time values is not enough to make the car run well. If you’re upgrading from stock Miata injectors or similar, your entire fuel table must be re-tuned. This is because EV14 injectors use a completely different internal design, and their flow characteristics vary non-linearly across different pulse widths. It's not just that 640cc injectors flow ~3x more—they also behave very differently at low duty cycles and transient conditions. Be prepared to fully retune your VE/fuel table from scratch.

Dead Times

MS2 users should use only the base dead time (at 13.2V) and the voltage correction (offset per volt) directly from the chart.

• MS3 users, Haltech ECUs, and ME221/ME442 (ME2x) systems running modern dead time models (e.g., Megasquirt 1.6.xx firmware) should instead use the calculated dead time in microseconds (µs), derived from the injector’s voltage offset percentage using the following formula:

Dead Time (µs) = Base Dead Time × (Voltage Offset % / 100)

Each injector chart (e.g., FF380, FF640, FF725, etc.) includes both:

• The base dead time at 13.2V
• The voltage offset %
• And the calculated µs dead time per voltage level (11V–16V)

Use these µs values directly in your dead time table if you're using:

• MS3 (with firmware 1.6.xx or later)
• Haltech Elite/Nexus
• ME221 / ME442 (ME2x)
• Any ECU that supports voltage-based dead time mapping

Fuel Pressure Reference

Unless your fuel system is modified:

• 1990–1997 NA Miata's use 3.0 BAR fuel pressure
• 1999–2015 NB/NC Miata's use 4.0 BAR fuel pressure

Be sure to reference the correct column (3.0 BAR or 4.0 BAR) in your injector chart.

Happy boosting!