Using A Rb25det Pfc On A Rb20det

[carl h]

ok so its been said it can be done but you are confused to as how to do it, well no worries heres a short rundown of what to do...

remeber when using a rb25pfc on a rb20 you MUST upgrade injectors due to the r33 rb25det having 370cc injectors vs the 270cc injectors that came std on the rb20.

download the attatched pdf document, nevermind the fact that its for an r33 gts-t with an rb25det, the pinouts are the same for the rb20 except 2 pins.

on the pinout locate pins 112 and 114 on the ecu plug and carefuly using a small pin or piece of thin stiff wire remove these pins and swap them (you are swapping the triggers for injectors 4 and 6 around).

to do this you'll need to remove the clear ecu backing plug cover and then with the wire on the front side of the ecu there will be a small tab above the pin that needs to be bent back a bit to pull the pin out, i'll try to get pics later.

ok, now that you've swapped these pins start up the pfc and set the injector correction for what ever injectors you have, remember to install a resistor pack if you are using low impedence injectors...

if all went well when you crank the car it should start up and idle well on the first go, verify that afr's are good (which they should be as the rb25 pfc runs stuff silly rich...) and enjoy!

now go tune the car and terrorize r33 owners

RB25DET_ECR33_Pinout.pdf

Edited May 9, 2006 by carl h

[SirRacer]

ok so its been said it can be done but you are confused to as how to do it, well no worries heres a short rundown of what to do...

remeber when using a rb25pfc on a rb20 you MUST upgrade injectors due to the r33 rb25det having 370cc injectors vs the 270cc injectors that came std on the rb20.

download the attatched pdf document, nevermind the fact that its for an r33 gts-t with an rb25det, the pinouts are the same for the rb20 except 2 pins.

on the pinout locate pins 112 and 114 on the ecu plug and carefuly using a small pin or piece of thin stiff wire remove these pins and swap them (you are swapping the triggers for injectors 4 and 6 around).

to do this you'll need to remove the clear ecu backing plug cover and then with the wire on the front side of the ecu there will be a small tab above the pin that needs to be bent back a bit to pull the pin out, i'll try to get pics later.

ok, now that you've swapped these pins start up the pfc and set the injector correction for what ever injectors you have, remember to install a resistor pack if you are using low impedence injectors...

if all went well when you crank the car it should start up and idle well on the first go, verify that afr's are good (which they should be as the rb25 pfc runs stuff silly rich...) and enjoy!

now go tune the car and terrorize r33 owners

excellent post mate, you have given me hope with running one in my car now. someone said in an earlier post however that the firing order is different?

the link doesnt work also by the way.

Edited May 9, 2006 by SirRacer

[rice_me_up]

put this on the DIY thread. i reckon it should be attatched to the "power fc frequently asked questions"... perhaps...

thanks alot for that. should save me about 500 cos the rb20 pfc are that much more expensive than the rb25's.

cheers.

[Sydneykid]

ok so its been said it can be done but you are confused to as how to do it, well no worries heres a short rundown of what to do...

remeber when using a rb25pfc on a rb20 you MUST upgrade injectors due to the r33 rb25det having 370cc injectors vs the 270cc injectors that came std on the rb20.

download the attatched pdf document, nevermind the fact that its for an r33 gts-t with an rb25det, the pinouts are the same for the rb20 except 2 pins.

on the pinout locate pins 112 and 114 on the ecu plug and carefuly using a small pin or piece of thin stiff wire remove these pins and swap them (you are swapping the triggers for injectors 4 and 6 around).

to do this you'll need to remove the clear ecu backing plug cover and then with the wire on the front side of the ecu there will be a small tab above the pin that needs to be bent back a bit to pull the pin out, i'll try to get pics later.

ok, now that you've swapped these pins start up the pfc and set the injector correction for what ever injectors you have, remember to install a resistor pack if you are using low impedence injectors...

if all went well when you crank the car it should start up and idle well on the first go, verify that afr's are good (which they should be as the rb25 pfc runs stuff silly rich...) and enjoy!

now go tune the car and terrorize r33 owners

So you swap the injecting timing, but not the ignition timing. Is that right?

cheers

[paulr33]

thanks for clearing up, will add to the fAQ tonight

[dangerous_daveo]

Is anyone able to confirm that they have actually done this to their car? No offence intended. But I could type up the same thing without having actually done it.

[sidewazegtst]

For sure I'd like to know if anyone has had success with this too. It would save all the RB20 guys lots of money that could be spent on, oh I don't know...... larger injector's maybe.

Anyway, super write up and I look forward to the pic's you were talking about and maybe you could fix the link to that pin out so we can download.

I'll be keeping an eye on this thread for sure!

Cheers

[paulr33]

updated powerfc to reflect correct info, thanks guys

[sky30]

Yeah, carl h, have you done this to your car and it worked?

Anyone else tried it?

[SirRacer]

Sydneykid can you explain that comment, seems to have some merit behind it

Any information on this or successfully using a gtr power fc in rb20 would be great

[grigor]

I think SK is suggesting anyone who just swaps 2-wires and some injector numbers is dreaming.

There will be a lot of re-mapping involved which will eat into the $500 odd price saving.

[carl h]

perhaps, but if you are taking the car to a pfc tuner then they can copy the fuel/timing maps from the rb20 base map and put it into the pfc.

we did try this on one of my friends cars and it does indeed run fine...i'll see if i can get copies of the base maps from the rb20/25 and do some comparesons between the 2 but i doubt that besides where the vtc kicks in and out it wont be any diffrent...we'll see.

oh and heres a copy of the r32 ecu pinout for anyone caring to compare.

[Sydneykid]

Sydneykid can you explain that comment, seems to have some merit behind it

I thought it was obvious, changing the injector timing (swapping 4 and 6) and NOT swapping the ignition timing means that the injector on #4 fires when the ECU is telling #6 spark plug to fire. I don't know about you, but that seems wrong to me.

Logic tells me that if you swap the injector timing you should also swap the ignition timing to match.

Any information ... successfully using a gtr power fc in rb20 would be great

The usual question is 2 AFM's on an RB26 versus 1 AFM on an RB20. Simple answer is to just parrallel up the ECU inputs for the AFM signal. So the ECU thinks that there are 2 AFMs with exactly the same voltage output, which fine and dandy. If you use the RB26 PFC you can add an inlet air temp sensor and use the PFC correction map accordingly.

My own RB20 uses an RB20 PFC, which is now used on the RB31DET. If pushed, I would always use an RB26 PFC on an RB20 in preference to an RB25 PFC.

cheers

[carl h]

I thought it was obvious, changing the injector timing (swapping 4 and 6) and NOT swapping the ignition timing means that the injector on #4 fires when the ECU is telling #6 spark plug to fire. I don't know about you, but that seems wrong to me.

Logic tells me that if you swap the injector timing you should also swap the ignition timing to match.

The usual question is 2 AFM's on an RB26 versus 1 AFM on an RB20. Simple answer is to just parrallel up the ECU inputs for the AFM signal. So the ECU thinks that there are 2 AFMs with exactly the same voltage output, which fine and dandy. If you use the RB26 PFC you can add an inlet air temp sensor and use the PFC correction map accordingly.

My own RB20 uses an RB20 PFC, which is now used on the RB31DET. If pushed, I would always use an RB26 PFC on an RB20 in preference to an RB25 PFC.

cheers

i dont think that, that logic is quite right.

firing order for all rb motors is the same no, and if it wasnt then you wouldnt be able to run a wasted spark setup on the motors wiring them the same way.

the only diffrence between the 2 ecu's is the vtc trigger, boost solenoid trigger, and clys 4 and 6 triggers being swapped other than that both carry the same exact pinout.

if i could get this picture of the r32 ecu plug to upload you would see what i mean...

we'll slap the pfc back on my friends car this weekend....see if we cant get video proof .

[KamikazeR33]

im hoping redtop and silvertop rb20dets are the same as im sticking in a rb25 powerfc in my r31 shitbox

it should b the same n all

if it dont work ill just use it on my r33 and sell that damn crapola microtech....

[MattSR]

carl is correct, For some reason Nissan swapped the injector pins but not the ignition triggers. Looking at the ECU pinouts will show that this is the case.

[sky30]

OK, anyone used a RB26 power FC to run a RB20???

SK:- how do you wire the AFM if you use a RB20 loom which only has one AFM wiring??

[paulr33]

you wire it directly to the pinouts, bypassing the wiring loom

im pretty sure anyway. it makes sense, as they are on the pinout for the ecu connector, just not on the loom.

much like the airtemp sensor. the ecu has physical pin, but the loom doesn't

[carl h]

you wire it directly to the pinouts, bypassing the wiring loom

im pretty sure anyway. it makes sense, as they are on the pinout for the ecu connector, just not on the loom.

much like the airtemp sensor. the ecu has physical pin, but the loom doesn't

a bit off topic but what does the air temp sensor look like?

ive seen it on the rb26 but it would be nice to see what it physicaly looks like, i might try fitting one to my motor and seeing if the pfc will read it...

[BHDave]

I think someone tried wiring it into an rb25 pfc and popped it a year or so ago. Whether it was wired wrong or the 25 pfc just uses that pin for something else i dont know.