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Rb20 Loom & Ecu To Run Rb25

4g6beat

By 4g6beat,
in Engines & Forced Induction

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4g6beat Apprentice

4g6beat

Posted
Posted

Hi Guys,

I've found plenty of info in regards to putting an rb25 into r32 using the 25 loom & Ecu. Also there's plenty of info on using a rb20 ecu on a 25 loom but cant seem find info on running an rb25 using a 20 loom+ecu.

The reason i ask is because i'm doing a conversion and already have a rb20 power fc wired in with a q45 afm and big injectors and was wanting to know why i cant just swap everything (all sensors + CAS) over onto the rb25 and just tune it to suit. I'm not fussed with vct as i'm going solid lifters.

Also i have a greddy plenum with the rb25 will the 32 IAC fit? Is there anything obvious i'm missing out on by not using the 25 loom?

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https://www.sau.com.au/forums/topic/256546-rb20-loom-ecu-to-run-rb25/
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  • 6 months later...
XRATED Veteran

XRATED

Posted
Posted

I'm considering an RB25DET as a replacment for my rb20det (that is destroyed). I too went through all the threads I could find on 25 swap into a 32. I didn't seem to find too much info on running the 25 using a 32 loom and computer. I'm not too fussed about the VCT as I can play with that later.

Any info would be great.

Cheers

Justin

  • 2 weeks later...
grandmasterb Grand Master

grandmasterb

Posted
Posted
IMO is easier to just get a RB25 loom and make it fit your R32, you can still use your RB20 power fc too

Most defiantly but that wasn't what he asked was it Simon :D

I was under the impression that you couldn't use a RB20 pfc for RB25 unless it was also modified accordingly???

Simon-S14 Grand Master

Simon-S14

Posted
Posted

lol i read what he asked and i saw that you gave the correct answer, so i just chipped in my opinion :D

If you want to make a RB20 loom fit a 25, the S1 motor is the one to do it with, injector plugs and knock sensor loom need to be changed along with quite a few other things.

a RB20 PFC will run a RB25 no worries, as will a RB20 ecu. doesnt matter if its series 1 or 2. It just wont control VCT.

grandmasterb Grand Master

grandmasterb

Posted
Posted
lol i read what he asked and i saw that you gave the correct answer, so i just chipped in my opinion :D

If you want to make a RB20 loom fit a 25, the S1 motor is the one to do it with, injector plugs and knock sensor loom need to be changed along with quite a few other things.

a RB20 PFC will run a RB25 no worries, as will a RB20 ecu. doesnt matter if its series 1 or 2. It just wont control VCT.

HAHA i know i was only throwing the line out mate :D

I didn't think you could use a 20 ecu on the S2 25 because of the ignitor set up???

Simon-S14 Grand Master

Simon-S14

Posted
Posted

well guess what mate... you can :D

My neighbor bought a S2 R33 which i did all the work on, fitted fmic, exhaust and a host of other basic upgrades. I chucked the R32 ECU out of my 32 drift car which ran a s1 RB25 into this S2 R33 and it ran straight away. So i got him another 32 ecu, then got it chipped and tuned for him and it made 215 rwkw with basic upgrades and stock turbo. Car has never run better.

Basically the way it works is that the ignitors are independent to the ECU, the ECU provides the coilpack a trigger signal and the ignitor on top of it gets that signal and fires the pack.

XRATED Veteran

XRATED

Posted
Posted (edited)

Why cant I use the rb20 ignitor module, coil packs on the 25?

My plan was to strip EVERYTHING off the 25 and fitt-retrofitt all the 20 ignition set up, sensors-etc. Any reason this wont work?

I have top feed injectors and rail for it, so injector plugs wont change. A Z32 so the afm plug will change anyway. Slip the 20 CAS inplace of the 25 CAS, swap oxy sensors, bolt the 20 knock sensors in place of the 25 sensors, swap out all the temp and pressure sensors from the 20 into the 25, use the 20 coil packs and ignitor module, and so on.

Then use an rpm window switch for the VCT and play with the idle controll.

Use the 20 ac comp and wiring, 20 PS pump, 20 ALT and wiring.

What don't I see... What am I missing???

Cheers

Justin

Edited by XRATED
Rapidflow Collaborator

Rapidflow

Posted
Posted
Why cant I use the rb20 ignitor module, coil packs on the 25?

My plan was to strip EVERYTHING off the 25 and fitt-retrofitt all the 20 ignition set up, sensors-etc. Any reason this wont work?

I have top feed injectors and rail for it, so injector plugs wont change. A Z32 so the afm plug will change anyway. Slip the 20 CAS inplace of the 25 CAS, swap oxy sensors, bolt the 20 knock sensors in place of the 25 sensors, swap out all the temp and pressure sensors from the 20 into the 25, use the 20 coil packs and ignitor module, and so on.

Then use an rpm window switch for the VCT and play with the idle controll.

Use the 20 ac comp and wiring, 20 PS pump, 20 ALT and wiring.

What don't I see... What am I missing???

Cheers

Justin

do that mate u won't have a drama, all the rb20 sensors and stuff on the the rb25. only no vct!!

done it a ton of times, just make sure u use the right impentence injectors or resistor pack

XRATED Veteran

XRATED

Posted
Posted
do that mate u won't have a drama, all the rb20 sensors and stuff on the the rb25. only no vct!!

done it a ton of times, just make sure u use the right impentence injectors or resistor pack

Sweeeeet!

Thanks for the input.

Cheers

Justin

  • 3 months later...
4g6beat Apprentice

4g6beat

Posted
  • Author
Posted

Hi Guys have pretty much got it all workinghowever idle is not great, and once it warms up the idle hunts like mad. does this sound like i don't have the iac working correct?

also what fit s on the purple connector on the iac fromthe rb20 loom? i've only got the solenoid hooked up and i've blocked off the larger diameter pipe and run the smaller diameter pipe after the throttle body.

4g6beat Apprentice

4g6beat

Posted
  • Author
Posted (edited)

Also on a side note the solenoid on the iac is an rb30 one as the motor i got didn't have a solenoid on the iac. i know it's a long shot but it looked to actuate the same way and bolted straight up however the 2 pin plug off it doesn't correspond to the rb20 loom, it has a green and white wire. would anyone hazard a guess as to what colour would be power or ground, and can hooking them up the wrong way round stuff something up on the ecu ?

Edited by 4g6beat

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