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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.
Details on the particular swap we did:
RB20 GTS4 AWD -> RB25 RWD.
The car's getting re-swapped for a rebuilt rb25 with modifications to the block to fit the awd system, or a rebuilt rb26. in the near future.
Anyway... onto topic here:
Wiring the car, 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.
If anyone has any other questions regarding this swap let me know, while its still fresh in my mind
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.
Details on the particular swap we did:
RB20 GTS4 AWD -> RB25 RWD.
The car's getting re-swapped for a rebuilt rb25 with modifications to the block to fit the awd system, or a rebuilt rb26. in the near future.
Anyway... onto topic here:
Wiring the car, 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.
If anyone has any other questions regarding this swap let me know, while its still fresh in my mind
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