Hi,

I have a 1990 Nissan 300zxtt. I'm upgrading my injector to Border Racing injector kit. They make a kit for my car which includes fuel rails and 6 850cc side feed (hi impedance) injectors. Anyway, I know that their injector is identical to the 1993+ RX7 FD 850cc OEM injector (maybe even the exact same injector).

I have the option to buy just the rails. I am wondering does any company makes/sells 1000cc side feed hi impedance injector which is direct drop in for the FD? The 850cc injector might not be enough for my application.

Thanks!! I am sorry my first post here is not even RX7 related.

 

I don't know of any off the shelf 1000cc side feed injectors, but I also haven't searched extensively. You can have the 850cc injectors bored out 1000cc or even up to 1300cc. Though I can't say that I would recommend going all the way to 1300cc because of a reported failure rate increase.


RC Engineering can do this for you.

 

No such thing as 1000cc side feed stock. You'd have to get the 850cc's bored out to 1000cc side feed like ISUposs stated.

 

I have a set of 960 side feed injectors that I was using up until I went to 1300s. Let me know if you are interested. I also have a FD stock fuel rail.

 

Another option besides using larger-than-850 injectors would be to increase your fuel pressure.

new_flow = SQRT(new_pressure / old_pressure) * old_flow

To figure out how much pressure you need to match the flow capability of 1000cc injectors with 850cc injectors, plug your current pressure (old_pressure) into this formula:

new_pressure = (new_flow / old_flow)^2 * old_pressure

new_pressure = (1000 / 850)^2 * old_pressure

new_pressure = 1.384 * old_pressure

So, if your old fuel pressure is 40 psi, you will need 1.384 * 40 = 55.36 psi of base fuel pressure to match the flow of the 1000cc injectors (at 40 psi) with 850cc injectors. Please note that your rail pressure will vary with engine vacuum and boost, so be sure to take the initial reading and make your adjustment with the engine idling and the manifold reference hose to the fuel pressure regulator disconnected, or with the engine stopped and the fuel pump running.

That might be the best option if you need to use side-feed injectors. AFAIK, the 850s from the RX-7 are the largest side-feed injectors available without modification. Modification would be pretty expensive for 6 injectors (about 6 x $150 = $900). If you are only looking for 150cc extra flow, it seems like it might be far more cost effective to get an adjustable fuel pressure regulator (with 1:1 manifold boost reference) and raise the pressure a bit. You'll also need a fuel pump that can meet your flow needs at the higher pressure (55.36 + max_boost + fuel_system_pressure_drop psi).

I wrote a web page form that can be used to play with the numbers if you are interested:
http://www.maxcooper.com/rx7/how-to/...tem/calcs.html

Mmmm... 658 RWHP.

-Max