Converting From Rb20 To Rb25

[DuFFR32]

Well im about 99% certain ive lost a cylinder on the 20' So im looking at doing the RB25DET conversion as its not much more expensive for a 25.

Just wondering if the HKS2530 turbo i have on the 20 will be alright to put on a 25 and will my GTR injectors and Z32 AFM go in alright?

My ecu is a nistune item will I need a 25 ecu or can the 20 ecu be tuned for the 25?

I believe there is a lil wiring involved changing the 20 loom for a few bits and pieces and so on covered in some of the posts ive read.

Any info is appreciated

Cheers, Rohin

[WARLORD]

  DuFFR32 said:

Well im about 99% certain ive lost a cylinder on the 20' So im looking at doing the RB25DET conversion as its not much more expensive for a 25.

Just wondering if the HKS2530 turbo i have on the 20 will be alright to put on a 25 and will my GTR injectors and Z32 AFM go in alright?

My ecu is a nistune item will I need a 25 ecu or can the 20 ecu be tuned for the 25?

I believe there is a lil wiring involved changing the 20 loom for a few bits and pieces and so on covered in some of the posts ive read.

Any info is appreciated

Cheers, Rohin

yes to all but you need a fuel rail,2530 is to small but can be used,z32 you need a different harness.

[TRB-001]

easiest thing to do is use all your rb20 sensors and electrical components.... then u dont have to change the harness or ecu.

ull have to either find the right fuel rail and injectors to fit or use the rb25 injectors and just match up the wiring, very easy.

if the z32 afm is already installed, there will be no issue.

so things like your coilpacks, transistor pack, coolant temp sensors, knock sensors, just swap them all over from the rb20 and plug it in, as i said the only mod will have to be ur injectors if u cant get a fuel rail to suit (the rb20det fuel rail mounts different then the rb25 so its not a straight swap.)

any more question, let us know.

[bubba]

Rb20 Nistuned ECU won't run the VCT on the RB25..

Z32 AFM just needs the matching plug swapped off your RB20 loom onto the RB25 loom.

Injectors, as mentioned, are not a straight drop in (RB20/26 are top feed, RB25 is side feed).

[TRB-001]

sorry yeah i forgot about that part of the conversion, either diable VCT and run r32 ecu, or look into getting the rb25 ecu and power fc

[bubba]

What the Nistune guys do for RB25's is run a Z32 ECU so you can still use VCT.

[XRATED]

run an rpm window switch to turn the vct on and off.

J.

[Sheriff Wan]

Also depends on series 1 or 2 RB25

If your using a series 2 you cannot use the coilpacks from your RB20. As already stated - you will loose VCT if your not using a 25 ECU.

Also I'm running a 2530 on my Rb25 - HEAPS of response but its about as small as you'd want to go.

[DuFFR32]

Ok so basically just to get it going i will keep the standard injectors in place. With the Z32 AFM i have both plugs there so I can use either standard or Z32 which is awesome.

Also ive been told a 300ZX computer will work with an RB25 is this true?

and yeah I know the 2530 will be too small so I guess I will eventually sell it for a bigger unit

so basically all i have to sort out is wiring and heater hoses is there anything else?

Awesome info thanks a million

[TRB-001]

shouldnt be, top radiator hose is different but just match something up at ur auto shop, i got a commodore hose and cut it from memory.

and yeah, u can only use the rb20 coils if u use the rb20 ecu

pretty much, all the electricals have to match the ecu.

[JonnoHR31]

could always buy a 32 rb25de and put all your 20 stuff on it

[bubba]

  JonnoHR31 said:

could always buy a 32 rb25de and put all your 20 stuff on it

I did that but put a 3L bottom end under the 25DE head

[JonnoHR31]

even better and piss easy with a 32 head

[DuFFR32]

an rb20 head wouldnt flow enough with a 3L bottom end though?

I want the easyest conversion possible lol

[JonnoHR31]

i meant 32 25de head, cant use 20 heads, different size bore

[rb20lover]

has anyone used rb20 loom and plug-in ecu(link, haltech, adaptronic) to run an rb25???