460cc injectors fitted

[ROB-80E]

Well guys, I've finally got round to fitting the 460cc Series IV (i think) 13b N/A injectors I got off ebay ages ago. Reasons for not fitting was that after I'd been told that all RX7 injectors are bolt in, THEY AREN'T. In the RX7's, any of the Peak and Hold series injectors (low ohm/impedence) have a bigger nozzel than the Saturated (high ohm/impedence) injectors found in the later 13b N/A engines.

I had the injectors serviced prior to fitting...this included replacing the nozzel caps, head seal (grommet), top grommet, o-ring and also cleaned and flow tested. Cost was $30/injector.

Well anyway, fitting wasn't hard once I got started. Intake pipes and intake manifold were removed so that I could insure that no metal would get inside the engine. With making sure the valves were closed and a rag wedged in the port I proceeded to drill (with gritted teeth) the injector ports in the head larger. The standard port is 9.5mm and I redrilled exactly 1mm larger and this made a perfect fit for the nozzels on the new injectors.



Apart from the head ports, these injectors fit perfectly into the standard GTX fuel rail.


Again the difference with the low ohm injector out of the RX7 is that the plug is different...I already had a set of plugs lying round in the spares bucket to suit, so it wasn't hard to me to chop and solder and heat shink the plugs into the injector loom I made for the Microtech. Because I do have an aftermarket ECU, I don't have to worry about a resistor pack...they just plug straight in and the Microtech will drive them with no problems.


I have already started the car and as expected it was very rich. Haven't attempted to drive it yet....will do that tomorrow and attemp a quick road tune with ajusting the injectors pulses down to a safe level that I won't go through a tank of fuel a day and stuff my spark plugs before I can get it retuned for more boost and power :D

Aim is for min of 220WHP on whatever boost the mighty VF10 hybrid will manage. heheh.

[ne3ek]

I'd been told that all RX7 injectors are bolt in, THEY AREN'T

I found that out the hardway lol.

[lscrx]

drilling out the injector ports.... you have cojones bro!

[Kreator]

muaha. Fit the n/a rail perfectly though. And they cost me $15 shipped.

[ROB-80E]

I found that out the hardway lol.

Hehehe, yeah so did I.

drilling out the injector ports.... you have cojones bro!

Yeah I wasnt keen at first to go drilling out my BPD head, but worked up the courage and bought a new drill bit and went for it. Very easy in the end.

[FE3-323]

UPDATE both low & high ohm injectors have the larger pintle cap & injector body. I have both in my hand, & i compared them to GTX 330cc's
As well the high impedance injectors have yet a different plug yet from the low.
noted by the location of the protruding plastic tab moved more to the right on the injector plug.
the low impedance injectors have the tab directly in the center.
all stock injectors are oval plugs the RX7 use D shaped.

[323GT-R]

I'm surprised you had to drill the head, I previously had RX7 550cc injectors in my GTR, and am now using Sard 700cc injectors, and they both have fitted straight in! I've also swapped to a different head, and they went straight in that one too! Yes, it's a close fit, but they fit without having to use any great pressure, and neither head has been drilled. What I did notice though, is that the fuel residue builds up around the head of the injector where it goes into the head, so if you're using 2nd hand injectors, you need to clean this up first, then they go straight in, no drilling required.

I've just bought some 800cc injectors as part of my next planned upgrade

[ROB-80E]

The 550's have a smaller pintle cap compared to the 460's. The 550's are the same as the GTX/GTR standard injectors. This is why you didn't have to drill.

BPT323, do you have the part numbers there mate? There's a few guys on FL.com that would be interested in the info with the part numbers. They are creating a injector database and listing interchangeability as well as associated issues (eg, yours and mine).

Cheers
ROB.

[323GT-R]

Got you. I'll give them a measure later, I know they are bigger than the stock GTR ones. Sounds like the 550s would be an easier upgrade for most people then, just need to swap the electrical connectors over.

[ROB-80E]

The actual ends of the injectors (the pintle cap) will be exactly the same. The GTX, GTR and the 550cc caps should all be 9.5mm, where as the 460cc RX7 n/a low ohm (square plug) ones have a 10.5mm cap.

Yep that's right the 550's are an easier upgrade...but you can also get a 13b N/A injector that is a direct swap too. I didn't go 550's because I didnt want the fuel inefficiency of 550cc injectors on a daily driver. Plus the 460's I knew I wouldn't exceed there flow capabilities for the power i wanted.

FOr people wanting well over 300HP at the wheels, I think 550's are the go. Otherwise stick with the standard ones or the 460's will do the job of the stock GTR ones as well. Just for interest sake, I've just fitted the GTR turbo, and with a retune I made 273HP at the wheels with the 460cc injectors. :D

[D323]

FOr people wanting well over 300HP at the wheels, I think 550's are the go. Otherwise stick with the standard ones or the 460's will do the job of the stock GTR ones as well. Just for interest sake, I've just fitted the GTR turbo, and with a retune I made 273HP at the wheels with the 460cc injectors. :D

Very nice. How much boost was that at?

[mikeflys1]

hmmm 460's fit my n/a motor perfectly

[Denis]

RX-7 turbo II
550cc/min high impedance drop right in and plug in wire harness
550cc/min low impedance drop right in but do not plug in to wire harness

Mazda thought they would be funny and randomly change from from low to high impedance injectors on the same year car. Lesson is make sure you get the right ones the first time.

[323GT-R]

The high impedance ones have a square connector, so they don't plug right it. At least the set I have here have a square connector...

[Lex]

How many HP do you guys think the stock GTX 330ccs are good for?