RB25DET with RB20 ECU

[Legionnaire]

I have just read in the near thread about some great results of using RB25 non-Neo/RB20 ECU combo. As far as I know, such a hybrid is possible only on S1 RB25's which ecu has blue two row connector. I have two questions in this respect:

1)Is it possible to swap a S1 wiring loom to a SII RB25 to use this mod? Any side effects? Lost features?
1.1)Is there any other mappable (with NIStune ) nissan ECU to use on SII RB25's?
2)What is needed exactly to use RB20 ECU on RB25? what wires/contacts need to be changed?
3)Does it matter what ECU, AT or MT, to use?
4)Is there any way to make VTC work?
5)Any other options to manage RB25's? 300zx ECU?



Let's put all the info on this topic in here

[Matt]

I'm going to paste some stuff from other threads here

http://ecu2.forumwise.com/ecu2-thread1812.html

R32 ECU

When using the R32 ECU to run the R33, do you have to switch injectors 4 & 6 ECU pins?
I just checked the pin out info that i have for both ecus and yes it does look that way.
If you want to use the RB25 ecu you MUST switch injector 4 and 6
If you want to use the RB20 ecu with the RB20 wiring you leave it alone
If you want to run the RB20 ecu in a car with RB25 wiring, you swap the wires as well

im thinking it still will work using a tuned rb20det ecu in the series 2 engine/loom with no wiring mods other than VVTi ...

- VVTi wont work using the R32 ECU, but most people either hard wire this or use a relay RPM driven mechanism to drive VVT. Most reports have indicated it doesnt really make that much difference to be to concerned about

Z32 ECU

- A z32 ecu can be used and it will control the nvics system.
- Wiring changes would include inj & ign driver mods to suit firing order and to reverse the polarity of the steering rack switch.
- Not sure about the knock sensor wiring as z32 only has one.

Changes list on our site:
http://ecu2.forumwise.com

R33 pin 19 to Z32 pin 34
R33 pin 105 to Z32 pin 110
R33 pin 110 to Z32 pin 105
R33 pin 112 to Z32 pin 114
R33 pin 114 to Z32 pin 112
R33 pin 57: cut
Z32 pins 29+52 : join

* I had an email about one of the above is the wrong pin, but cant find it right now. Double check each pin to ensure it doesnt go to somewhere it shouldnt against ECU pinout diagrams


Answering questions
1. Dont need to really swap the loom over
1.1 Use either R32 or Z32. Z32 will give you VVT control parameters and apparently works better with the TPS. Use a Type 2 board with these. Copy the maps from the R33 using one copy of Nistune running over the factory maps on the R32/Z32 ECU. Then adjust your injection latency manually afterwards using injector resize and AFM resize to get ballpark start figure
2. See above
3. Doesnt matter AT/MT ECU since when you rechip it you can put a new ROM in there with matching transmissions
4. Yes on the Z32 ECU, workaround on the R32 ECU
5. Using aftermarket daughter board and emulator. Some people do this, but the board is expensive. I've installed a few here

[Legionnaire]

Great info, Matt, thanks a lot! Exactly what I wanted to know.

IIRC, VG30 and RB25 injectors are the same, so all I need to do when swapping to Z32 ECU is to adjust values for 30P00 AFM.

The only thing I'm a bit concerned about with V6 ECU is firing order, being 1-2-3-4-5-6 on a VG, and 1-5-3-6-2-4 on a RB. It can be swapped over with pin swapping magic, but what about firing spacing? RB has even 120 deg of spacing, whereas VG, if memory serves me well, is 90-150 deg
Oh, and do VG30DE/TT's and RB25's use the same cam position sensor?

[Zuikkis]

When using the R32 ECU to run the R33, do you have to switch injectors 4 & 6 ECU pins?
I just checked the pin out info that i have for both ecus and yes it does look that way.

A bit old thread but I'd like to clarify a few things.

In ECU pinouts, injectors 4&6 are swapped. However, there is no need to fix that. If you look inside R32 rb20det ECU, you'll see that it only has two injector drivers! One for injectors 1,3,5, other for injectors 2,4,6. So injectors 4 and 6 are the same signal, the pins are connected directly to each other anyway..

The bigger problem is the TPS. HCR32 has separate idle switch, ECR33 doesn't. If you just plug in the R32 ECU, it will run idle at about 2000rpm and suffer from many other things caused by the lack of idle switch signal..

RB25DET TPS does have the idle switch, it's just not connected to the ECU. You can connect the wires yourself, it's ECU pins 54&57 that should be connected together when at idle..

I actually made a small circuit that monitors TPS voltage, and feeds 12V to pin 54 when TPS voltage is below 0.5V.. This works pretty well, and allows me to sell "bolt-on" ECUs which have this circuit built inside the box..

[Matt]

also possible to do a firmware mod on the HCR32 to use the TPS voltage and ignore the TPS line. speedlab on here has done it but I havent got around to it yet

[aleks]

Can some some clarify....

R33 pin 19 to Z32 pin 34 (Oil Pressure Switch....How about R33 pin 34 and Z32 pin 19 leave disconnected? I can't find these pins in any of the wirring diagrams)