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Roy

Gtr Injectors Into Rb20det

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Shopping around for injectors you often see GTR owners selling their 444cc injectors cheaply. I have seen them from as low as $200 up to $400.

First thing, whilst this can make for a cheap injector upgrade, i would hope you spend the extra cash on getting the injectors cleaned and flow tested just to make sure the 2nd hand bargain doesnt turn into protracted suicide:)

So first things first. The injector itself is identical to the injector used in the std RB20DET silver top engine. If it wasnt for the injectors being different colours then you could make the mistake of re-installing the original injectors. (red v yellow)

So if you can remove/install the std injectors then you can install the GTR injectors. No changes required to plugs, mechanically they are identical:)

The only problem is the resistance of the GTR 444cc injectors, and the difference to the std RB20DET injector. From memory the GTR injector is around 2.5ohm. The std RB20DET injector is around 12ohm. So running the the re-written ECU or an Apexi Power Fc with the injectors will damage the ECU unless the impedence differences are addressed.

Funnily enough the GTR ECU also needs to see a high impedence just like the RB20 ECU. However it gets away with using the low impedence 444cc injectors by using a ballast resistor from the factory. If you want to use the GTR 444cc injectors with your RB20 then you will need to get your hands on this ballast reistor as well.

So the installation of the injectors is a cake walk for most ppl mechanically minded. The surprise is its also very simple to wire in the ballast resistor which will mean your R32 ECU will happily run the larger injectors.

I strongly recommend you get your hands on a copy of the R32 GTST/GTR wiring diagram. The fact that the two engine types are on the one wiring diagram makes it very easy to suss out the wiring. You can get the diagram from rb20det.com or megalla.com

Following is a bit of a punch list/photos to help with the wiring of the ballast resistors. It can be done with the wiring loom on the car, in fact it is easier. The photos are with the loom removed because i was replacing mine meaning i had to once again wire in the resistor pack into my new harness.

How it works

Effectively the injectors are turned on / off by the ecu. All injectors are fed by a common 12V power. The injectors are then wired to the ECU independant of one another and are switched/open - closed by the ECU in order to fire the injector as required

So in order to cheat the ECU you need to be sure that the power supply to each injector passes firstly thru the ballast resistor

Resistor Pack and Plug.

462RB26_Inj_Resistor_Plug.JPG

You can see that the plug that goes to the resistor pack has 7 wires. The red wire is the 12V power supply to the ballast resistor. The 6 blue wires are the new power wires to each injector. ie remember that the injectors are all fed from a common 12V power wire, so all we are doing is taking the existing 12V power wire and diverting it to the ballast resistor, and using the 6 blue wires to go to the injector.

The Wiring

So once you have removed the RB20 injector and installed the GTR injector, you will need to wire up the resistor pack. So prior to re-connecting the plugs to the injector you need to identify the appropriate wires.

462Std_RB20DET_Inj_Loom.JPG

Here you can see the injector plugs taped as per std. The looms std 12V power wire feeds the front 3 cylinders directly, then goes into a plug above the thermostat that doubles back along the fuel rail supplying the injectors for cylinders 4 thru 6. The above pic shows the plugs for the front 3 cylinders, but is the same for all:)

462STD_RB20DET_Stripped_Inj_Loom.JPG

Here you can see the injector wires without the electrical tape. In the bottom right hand corner of the pic you will see where the 3 wires are spliced into one another. So this is where the common 12V power wire is spliced to feed all the injectors. You can also see a wire running off to the left, that is the common 12V power wire running off to the plug that feeds power to the rear 3 injectors mentioned earlier.

462RB20DET_Inj_Loom_Cut_I.JPG

So being sure you have identified the wire that is common to all the injectors, then feel free to cut the 12V power wire and seperate the wires as per above. Against the cardboard in the middle of the packign tape (just below the texta mark) you will see the cut 12V power wire that use to feed all the injectors. Connect this wire to the red wire to the resistor pack.

Effectively the power wire is now going directly to the resistor pack. In the above pis you will see that the wires have been curled up, we now connect a blue wire from the resistor pack to these wires. 6 injectors, 6 blue wires to solder together.

Solder them together in a neat orderly manner, and wrap them carefully with electrical tape to be sure that the joints will be free of moisture and unable to short out. And you are done:thumbsup:

So thats it. From parking the car to remove the injectors, to starting the car with new injectors and resistor pack will take about 6-8 hours being methodical and checkinng twice before cutting.

Note: You may not need the ballast resistor if you are running an aftermarket ECU that runs a range of different impedenced. For the record if you have a re-written std ECU or PFC then you NEED the ballast resistor. You will also need to get the ECU re-written to suit the larger injectors, other wise the engien will run very rich if at all:(

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Bump...a few ppl have been askign lately...drop me a PM if you need any additional info..or post here, plenty of ppl have done it these days so plenty of ppl will be able to help out...perhaps with greater detail

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roy.... that is SO helpful its not funny...

ive been wonderin how to wire in the resistor pack for so long... and now i can do it

thanks roy!

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thanks for that, its very helpfull

when getting the resistors off the gtr what price do they normally go for?

have you had any experience using rx7 (series 4&5) injectors?

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Thanks Roy, I have my injectors but am in need of the resistor pack.... Have you got a pic of one so I know what exacly to look for?

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Sorry, didnt see the question...ill dig up a photo tonight

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nice one roy

i also need a pic of the resistor pack - as i'm going to go find a r30 one - been told previously that these also work / or are the same?

thanks :)

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Hey Roy I am guessing you removed the Rb20DET resistor pack?

Also would you know the resistance from the power inlet to the outputs(injector outputs) of the GTR resistor pack and the stock resistor pack?

the reason I am asking as I am trying to work out the total resistance for the wireing system for both the GTR injectors and the stock injectors. (inclueding the resistor packs etc.)

I am looking/seeing if I can just swap the componenets in the ecu to allow me not to do any wireing.

I traceed out the pinouts of the injectors on the stock ecu and noticed that the ecu fires/grounds 3 injectors at once. (Batch fireing.)

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Christ...no idea...and playing with anything in the ECU is probably only for the brave.

If you look at the GTR vs GTST wiring diagram you will see that the GTST does not have any ballast pack etc so no need to remove anything.

I can tpost pics while the gallery is down :)

...and power outputs???? I can readily measure the resistances, but have never measured the voltage so have no idea of current or power.

If i remember to take my multimeter i may try to measure the resistances of the GTR injectors...but im pretty sure they are around 4ohms (thats from memory...please check before doing anything with that figure)

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i've been told that if u get a remap - some tuners can retune and alter your stock ecu so that there is no resistor needed :S

anyone else heard of this?

i think i may just get a stock gtr one

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i've been told that if u get a remap - some tuners can retune and alter your stock ecu so that there is no resistor needed :S

anyone else heard of this?

i think i may just get a stock gtr one

That would not suprise me at all as It appears to be just a matter of changeing 2 resistor in the ecu.

I just need to spend some time going throught the stock loom and also I neeed to measure the resistance of the resistor packs etc to see if I can do this or not.

When I decide to sort this I will post up some pics etc. Just cant do it as my car is not down with me yet. :)

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Christ...no idea...and playing with anything in the ECU is probably only for the brave.

If you look at the GTR vs GTST wiring diagram you will see that the GTST does not have any ballast pack etc so no need to remove anything.

I can tpost pics while the gallery is down :)

...and power outputs???? I can readily measure the resistances, but have never measured the voltage so have no idea of current or power.

If i remember to take my multimeter i may try to measure the resistances of the GTR injectors...but im pretty sure they are around 4ohms (thats from memory...please check before doing anything with that figure)

What I was hopeing was that you would know what the resistance is from the 12v feed pin to each of the injector output pins on the GTR Resistorpack.

If I know exactly what nissan used (what resistance) here I can work out the overall current etc and then I may be able to set the stock ecu to handle the low impeadance injector without changeing any wiring (See my above post.)

Sorry if I caused you all the confusion Roy.

Well for anyone elsefor that matter.

Dan.

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hmmm.....the pics are not available....can anyone re post the pictures???

thanks.....really need it for my next mod..............

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pm me your email addresses, i have the photos on my computer somewhere

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kinda on the topic of rb20det injectors can u high flow the stockies for more headroom so not needing the resistor setup??

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Sorry guys for not getting back to some of you as quick as i had hoped. I was kind of surprised by just how many emails i got...so have just updated the pics rather then email them all out.

As for high flowing the std injectors...i wouldnt do it, in fact i wouldnt even entertain the idea.

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Sorry for the noobish question but when soldering the blue wires from the resistor pack onto the injector wire does it matter which one u solder on to which injector? I don't imagine it would because of the way the power wire was common originally but better too ask now then be shitting myself when i do it...great D.I.Y btw :D

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Nope, as long as you solder the injector wires to the right blue wires then you are fine, they are not cylinder specific

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