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Rb26 Pfc Working On Rb20/rb25

Are you interested in a custom modified PFC to suit your RB20 and RB25?  

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As we all know Apexi have ended production of the RB20/RB25 PowerFC.

For whatever reasons, we don't care. There have been a few rumours surfacing around that the RB26 PFC will work on both the RB20 and RB25.

I expect that it *will* work but some changes are required to be made to make it work and be user friendly.

There are some known "gotchas" for either version and some unknown / risks as well.

Known changes:

- Injector wire changes

- Injector setting changes

- Airflow wire changes

- Airflow setting changes

- Stock map changes

- 02 sensor setting changes

Known "gotchas":

- RB25 version will NOT have working VCT support - The RB25 engine by default has variable cam timing. This is turned on at 1800rpm and off at 4700rpm.

Customers who have aftermarket exhauts cam gear are not affected by this known "gotcha'" as fitting aftermarket cam gear negates the VCT.

Jaycar have a product to build your own "rpm" on/off relay system but its completely manually and you would have to do it yourself.

- RB20 versions will face an issue with standard injectors and the correction involved. This is because we are limited to how much correction we can throw in.

We are fairly certain it will be OK and work acceptably, you will have to dial in more fuel in the INJ map than normal to make it work. I will provide stock maps to suit this.

- 02 feedback might not work. This is because the GTR PFC and stock ecu have no support for 02 heater control but GTST needs it

Bonus Features:

- Working airtemp support

The mainstream RB20 and RB25 powerfcs do not support airtemp. That is they do not have the AIRT sensor and do not use it.

The RB26 powefc does and you can simply purchase / find an airtemp and connect it up and it will work. This will provide air temp correction on the maps and show it on the hand controller

- Twin AFM Support

The "modified" version will support single or twin AFM depending on your power needs. So you can run say for example twin z32's or twin rb25s MAFS on your single turbo RB20 or RB25

- Twin 02 Support

The "modified" version will support single or twin 02 depending on your power needs. So you can run say for example twin 02 sensors if you have a twin turbo setup.

- Djetro Option

The mainsteam RB20 and RB25 only let you choose LJetro, that is the AFM only version.

The RB26 PFC lets you choose either lJetro (afms) or Djetro (maps) and either will work.

I am unsure at this stage if it would work and how feasible it is (ie: Djetro Rb20) as you would need twin MAP sensors in a suitable location.


I will obtain a stock Rb26 PFC and then with a suitable wiring loom adapter make the required changes.

I will use software to edit the stock RB26 settings to suit which ever engine combination you need (RB20 or RB25)

The loom that I had in mind


The wiring loom adapter or pass through lets me make changes to suit your engine and not hack your existing car loom.

This makes the 26 PFC still a 26 PFC and your car still a stock 25 or 20 engine / loom setup.

So you can sell the PFC as a stock 26 PFC (just do a DATA INIT before you do) and sell your loom or change to a stock Rb20 / Rb25 ecu.

The changes on the loom control include injector, afm and 02 sensor changes need and there is no secret "firmware" changes etc to it.

It simply makes it easy for me to do my changes and for you as a customer to go back to stock and negates the need for you to hack your own loom.

The PFC kit and loom (that I supply) will be a direct plug and play to your car. Plug in the loom to your current loom and then plug the loom into the PFC.

Thats it, Away you go, run the self idle learn procedure and you are done.

If you want to go back to the stock ECU or another ECU, remove the loom and plug it into the factory car loom. (no mess, no fuss)


I am trying this because there is an obvious lack of PowerFC's for the RB20 and RB25.

People have been resorting to buying them off ebay and other places for mega prices $1500+

I feel that it should be cost effective and relativity easy for the user to get a PFC hence the work I am doing.

I have my own full time job and this is not an ebay scam / make money deal.

I am simply offering a service to modify 26 PFC's to suit RB20 and RB25.


I will NOT provide a warranty, the ecu you receive off me is provided on a do so at your own risk.

If it fries your coilpacks, melts your CAS, cooks your ultra super cool cam gear, melts pistons etc I cannot be held responsible.

This is a completely UNSUPPORTED HACK and violates any warrannty / guarantee. Of course I will test each unit but there are always risks.

I have been assured that other than the changes mentioned above are fairly normaml and that its a direct swap.

!! What do AP Engineering do !!

AP Engineering for some time provide hacks on mainstream PFCs to suit other models.

The RB20 AP engineering unit is simply an RB25 ECU with removed VCT support and the minor map changes.

They even open the ECU ecu and cut tracks and make wiring loom solder changes to achieve the goal.

Whats next

This is a work in progress. It was originally setup as a done project but it hasnt been completed and didnt work out.

Someone else will need to take on the legacy here.

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Great idea, if I needed one I would be in.

I have had an RB26 Power FC running the RB20DET (before I bought the AP Engineering RB20DET PFC), so I know it will work.

:P cheers :

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yeah im interested possibly in this...

if it works out but anyhow anything cheaper than bs on ebay and works..

so yeah so i give my support.

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i would be keen pending price and that

so tuning wouldnt be a fuss? also do you "have" to run duel afm for it to work?

tuning wouldnt be an issue as its a normal PowerFC.

You don't have to run twin AFMs, the changes I make will make it use only 1 AFM and retain the stock RB20/RB25 wiring and AFM

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The price I have come up with is around $1250 for the unit.

This would include all the changes needed and the standard box, jap manual etc etc and shipping to your address via normal aust post.

The wiring loom alone costs about $200 and I have to allow for fluctuating aussie dollar / jap yen for the standard PowerFC unit.

The legacy AP Engineering units are $1499 with hand controller so I think my price is reasonable.

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If it will work on a 1996 s2 r33 put me down for one.


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Meh bye a wolf v5 and be done with it. easier to tune, no afm's better interface come with warranty not a no warranty hacked at unit that wont have any support. Dont waste your own time i can hardly see anyone being genuinely interested

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sounds like a champion idea bro my mate is has been looking for one for his rb20 for a while and he's keen as on it ! !

cheers ! !

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sounds pretty good, so it would be exactly the same a tuning a Ap eng. Fc on the 32's nothing different because its been tampered with?

Are you buyin the Rb26 fc's brand new? if so where from?

thanks simon

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The PowerFCs will be new from nengun. Hopefully, I can just work on makes changes to the wiring loom only and the stock FC is simply a 26 FC.

This would mean you would have to order the FC from nengun and the warranty would lie with yourself & nengun. I would supply the loom to suit and instructions on how to set it up to suit the RB20 or RB25. This would avoid me buying dozen's of 26 FC's and your normal warranty would be with the supplier directly. Otherwise I have to act as a proxy for the warranty on the FC

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I have spoken with my supplier and they will let me do the wiring loom changes for me so this makes it even easier than we thought.

I will simply setup the loom and required changes and then simply sell the loom to suit RB20 & RB25. It will be upto you to source your own RB26 PFC from either 2nd hand, new, nengun etc. I will provide some instructions on what to change on the hand controller before starting the car so it should be straight forward.

More to come when I find out total costs from the supplier, I am unsure how much they will charge me to setup the custom loom and make changes then batch build them.

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