Thread: Quick Injector Questions

I just wanted to clear up some questions I've been wondering real quick. I"m upgrading to STI injectors on my SR20DET and wanted to make sure i got a few things straight for my internal memory databank.....

SR20 = High Impedance, correct?
Therefore I need high impedance injectors to be simple drop in, no resistor....

Apparently not all STI injectors are high impedance I've noticed, so my main question is how do I tell the difference between the low and high impedance ones? What years are which? I just want to make sure I dont go putting low impedance ones in my rail and hurt the ecu

Yes, sr20 is high impedance with the exception of the gti-r injectors (low impedance).

There are two basic types of injectors. Low impedance injectors with a resistance of around 2.5-3 ohms, and high impedance injectors of around 12 ohms. This can easily be measured by a multimeter across the two electrical terminals. Dave

You can use a multimeter to measure ohms of each injector, 11-13 ohms is what your Nissan likes. Now if your upgrading to sti side feed injectors 525cc they should be the correct ohm range. Remember you will need injector harness plugs for these and a way to tune for them. Good luck

If there a way to tell like from looking at them? For instance like if i was going to buy them, i wouldnt have them test them first. I was just curious if there was a way to tell that way. Or perhaps a certain year I should look for to know I get the right ones. I've seen 550cc yellow tops say low impedance for sale, and another set of yellow tops for sale not say so I was just trying to figure out if there was a way to know besides asking so I can be sure myself....



Yeah i have like 3 pairs of Subaru pigtails and a Calum RT for tuning


For instance this is what is throwing me off. Heres an auction for STI injectors saying good for SR20 but they say the are low impedance so its not just like drop in...
http://www.ebay.com/itm/Subaru-Impreza-STI-injectors-550cc-Sr20-sr20det-s13-s14-240sx-/111314087653?pt=Motors_Car_Truck_Parts_Accessories&hash=item19ead62ee5&vxp=mtr

They are high imp. The guy writing the add is an ass clown (darn 240sx guys). Sti side feed inj should measure out at 11-12 ohms. While they are stated to be 550cc they flow 510-525cc most of the time. They can and will push more cc at higher fuel pressure.

Oh so those injectors are high impedance? He said he got them to put in an RB25 but they were low impedance injectors so he couldnt use them so he's selling.....hrmm


I was prob gonna try 4 bar with them eventually put this is just for my T28 setup

The eBay add says sti inj and those should be high imp. As for the Rb inj you would need to provide more info. Just check them with a meter.

Stick with sti 555cc inj if that's what your tuning for. I have used them on a few turbo setups and they worked great.

Keep it simple and dont be cheap on the injectors buy the real thing or pay the price later.

What i mean if the guy said he needed high impedance injectors for his RB project, thats why he was selling the injectors, cuz they are low impedance.......so your saying he's just an idiots and much have got wrong information lol, cuz im pretty sure RB25 is also high impedance as well

What skyline does he have? RB26 use low impedance injectors. I'm assuming he meant to say the injectors he has are high impedance and he need's low impedance and did not know this before he bought the subie injectors.

He's confused causing you to be confused! Dave

I emailed him to be sure cuz of my confusion and he said this....

"I bought them off ebay. About 6 months ago and the mileage was around 50k they said. I was going to use them but I need high independence injectors. They are all from a sti I bought 4 as a set and I needed a total of 6. And I only found one separate and was looking for 1 more until I found out that it will not work on my setup. I was going to use them on a rb25. I've used a set of sti injectors before on a sr20 and it worked great. I have had the set I used on my sr20 clean and tested and they said they are around 550cc"

See why im confused haha