Jump to content
SAU Community
  • Welcome to SAU Community

    Welcome to SAU Community, like most online communities you must register to view or post in our community, but don't worry this is a simple free process that requires minimal information for you to signup. Be apart of SAU Community by signing in or creating an account.

    • Start new topics and reply to others
    • Subscribe to topics and forums to get email updates
    • Get your own profile page, build reputation and make new friends
    • Send personal messages to other members.
    • See fewer ads!

    Consider joining our newsletter for the latest content updates

    Click here to register

Found A Easy Way To Do A R32 Rb25 Conversion

Recommended Posts

Hey guys,

After many hours scouring the interweb on everything for a R32 into RB25 conversion I have found a site with some very useful information.

As most of us know the RB20 and RB25 ecu pinouts is the same except for the Injector 4 and 6 pins. This site is saying that all you need to do is use the RB20 Engine Loom, swap the two injector wires over, and the plugs for the injectors and then you pretty much just plug the RB25 ECU in and your pretty much good to go.

All that would be left is the VCT which by the looks of the wiring schematic for the RB25 would just need the plug from a RB25 loom and wire the 2 wires in.

Can anyone confirm if this would work? I have been thinking about it long and hard and cant find any reason it wouldnt seeings the pinouts are basically the same.

If it does then it would make one hell of an easy conversion, as there would be no need to splice looms and everything would plug straight in.

I have heard of people using the RB20 loom and ECU, but not the RB20 Loom and Rb25 ECU...

Any input appreciated :)

Here is the site:


And heres the DIY from the site:

Well, there seems to be a certain amount of confusing regarding wiring when doing the RB20 -> RB25 swap.

I read quite a few conflicting things in my search for accurate information, and at the end of the day i just looked over the wiring diagrams, and plugs on the harness, and used little bits of information i read.

So with that, i'm going to post everything you need to do (which is really not much at all). swapping from rb20 to 25 is about the easiest wiring swap you could possibly do. This makes swapping a SR20 into a 240sx look like rocket science.

We will be using the RB20 harness, as its 100x easier, and has no downsides.

You will need:

-Complete RB20 harness including injector sub harness

-RB25 injector sub harness.

- (optional) a plug that will fit onto the VVT solenoid, and some wire.

1) Take the injector sub harness off the RB25. This is the one with the plugs for the sidefeed injectors.

2) Cut all the plugs off, leaving enough wire to solder them onto the rb20 harness.

3) cut off all the top feed plugs on the RB20 harness. 3 are on the sub harness, and 3 are on the main harness.

4) Solder the sidefeed injector plugs onto the RB20 harness and sub harness.

5) You must swap the wires for injectors 4 & 6. Doing this at the ECU is the easiest Just cut pin 112 & 114 and cross them and resolder.

If you have an afermarket ecu (such as in the case of this install), and you can configure your outputs, you can do this in software. In our case we used an AEM EMS... its nice because it supports the RB20, 25, and 26 with one unit.

6) If you want your VVT to work, you must get a hold of the right connector for the VVT solenoid. If you have an rb25 harness, thats easy just take it from there, if not take a trip up to the wreakers and snag one off some random nissan that will work.

Then just solder 2 wires to it, plug it into the solenoid, and wire it up into the ecu. We didnt hook it up, so i'm not sure on the exact wiring. I do know pin 113 is a trigger for the VVT. It would be easy to figure out with a wiring schematic. If you need help with this, post a schematic that includes the VVT solenoid on it, and i'll tell you how to wire it.

7) Your done. Make sure you use an RB25 ecu or calibration.

Link to comment
Share on other sites

a mate of mine told me he ran a rb20 ecu in his car (ceffy running rb25) when he was trying to sort out a fault and he didn't alter any of the wiring and it ran fine (he's generally not one to bullshit)

Link to comment
Share on other sites

Yeh there are a lot of people running rb25s with rb20 looms and ecus as the rb20 ecus are easy to reprogram.

I'm interested to hear if people can think running the rb25 with the rb20 loom but the rb25 ecu would work as the wiring looms are basically the same. Which would mean no need to splice the looms

Link to comment
Share on other sites

Use rb20 computer and loom with a nistune and it is even easier.

this. you just lose a little bit of low to mid range power from not having the VCT. if you use a z32 ecu though you can keep the VCT. just need to do a little bit of splicing.

Link to comment
Share on other sites

Then it's not really any easier. I was just thinking If someone was to do a conversion it would be easy if you only had to swap over a couple wires and your running. Then you could do the nistune on the rb20 later down the track. I think a lot of people find the hardest part of this conversion the wiring

Link to comment
Share on other sites

um how is that not easier you don't change ANYTHING on the ecu side, you don't even change a 'couple of wires' they ALL stay the same lol.

The msd switch or eboost is seperate, you just run 2 wires to the relay, 2 to power and 1 to RPM input off the ECU.

It doesn't get any easier than that haha

Link to comment
Share on other sites

  • 3 years later...
  • 4 years later...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Latest Posts

    • looking good mate keep up the good work i like following this thread.  
    • 20220120_204714.mp4     Hey guys, passenger door jammed shut on me, I managed to get the door card off in one piece and have a look in there but can't seem to find the problem. Ive tried using combos of using the key and holding the interior lock open, using both door handles and the central lock button. Ive tried pushing and pulling the door latch and lock rods manually The lock mechanism seems to turn and push the lever when I turn the key and everything looks to be in place. Cant for the life of me find the problem. Any help would be appreciated. If there is a manual way to open the door I haven't found it. Im guessing something inside the latch mechanism has gone bad but how can you get it out with the door jammed shut? 
    • There are literally dozens of aftermarket throttlebodies in DCOE carby format. The RB26 ITBs are so very very close to the DCOE bolt pattern that it is difficult to believe that Nissan came that close and didn't actually just use the DCOE pattern. Then, you can look at just about any EFI motorbike from Suzuki, Yamaha, Honda, etc that used single throttles, in whatever size floats your boat. 45mm? 48mm? Larger? They're all out there. Just build manifold and plenum and linkages to suit. As for compression and cams - the larger the cam duration, the more compression you can run. Just sayin'. And as for cost for bottom end.....8500 rpm is well within the limits of the stock bottom end. Especially NA. It won't cost much to make it good for >9000. Just need some light pistons and some moderately strong rods and bolts. On the subject of VCT.....all RB25s have it (except for the very first ones in the R32). The vanilla 25s in the R33 era cars were all VCT. There's almost no difference in the VCT between vanilla and Neo engines. The difference between Neos and vanilla 25s is that the Neos have solid lifters, a different included angle in the valves with a shallow combustion chamber. And in the NAs.....not particularly good flowing ports. I would not write off the power potential of an L series vs an RB25DE though, neo or not. 2.8L & 3L (and larger) L series builds, even running Mikunis, have made really large power. There is nothing wrong with the single cam engines. The twin cams are not inherently a massive leap in power potential.
    • Might need to make phone calls for garage plans before further car plans
  • Create New...