Jump to content
SAU Community

Neo Rb25det Questions

DRFT 14

By DRFT 14,
in Engines & Forced Induction

 Share

Recommended Posts

DRFT 14 Collaborator

DRFT 14

Posted
Posted

Hey there guys, ive just bought a NEO RB25DET motor out of a 1999 GT-T and an R33 25t gearbox to fit into my S14 (previously fitted with an RB20).

The motor is missing the ECU, alternator, wiring harness has been cut etc. Ive got a few questions regarding r33-r34 part interchange-ability. Will other RB alternators fit the NEO RB25? What about the wiring harness? And im guessing the ecu will have to be a NEO ecu, and an R33 ecu wont work? Will a DE wiring loom be fine on the DET, or do I need to hunt down a turbo loom?

Any help will be appreciated, as im not very familiar with the NEO motors. Thanx guys

Link to comment
https://www.sau.com.au/forums/topic/96901-neo-rb25det-questions/
Share on other sites
Bluprint Veteran

Bluprint

Posted
Posted

You will need the 34 DET Neo wiring loom, and ECU.

The electronic side of the R34 motor seems to be fairly different from an R33, so no you can't use the R33 gear.

I'm not sure on the alternators, though I'd imagine that you'd be able to use one from an RB20/25/26/30 without much trouble, I'm not 100% though.

DRFT 14 Collaborator

DRFT 14

Posted
  • Author
Posted (edited)

Thanks alot guys, I can always depend on getting quick useful replies in these forums :blink:. So, the verdict is that a neo computer and wiring loom is needed and other RB alternators *should* fit.

Another question, I have an Exedy 5 puk heavy duty clutch that i kept from my rb20det. Mint condition, was only in there for 1 month. Will an RB20 designed clutch bolt on to the RB25 gearbox? I really hope so! Also, will an R33 AFM work with a NEO computer?

Edited by DRFT 14
Craved Grand Master

Craved

Posted
Posted
Another question, I have an Exedy 5 puk heavy duty clutch that i kept from my rb20det. Mint condition, was only in there for 1 month. Will an RB20 designed clutch bolt on to the RB25 gearbox? I really hope so! Also, will an R33 AFM work with a NEO computer?

there are 2 different gearboxes from the RB25 .. push and pull types..

so you will have to work out what type your clutch is, then what type your g/b is!

caminperth Grand Master

caminperth

Posted
Posted (edited)
You will need the 34 DET Neo wiring loom, and ECU.

The electronic side of the R34 motor seems to be fairly different from an R33, so no you can't use the R33 gear.

I'm not sure on the alternators, though I'd imagine that you'd be able to use one from an RB20/25/26/30 without much trouble, I'm not 100% though.

What will plug in direct from R33DET gear:

CAS - but you will need to re-wire the plug by reversing the wiring

Injectors - plug straight in

Coilpacks - if you have a series 1.5 then it'll plug right in

Detonation sensors - plug straight in

Coolant temp sensor - plug straight in

Oil temp sensor - plug straight in

Stuff that will work from R33DET:

Throttle body

AFM

ECU

The R33 alternator will fit. The R33 air con and power steering units will not fit with the R34 harmonic balancer. Change it to the R33DET item and they will.

There's probably a few things I've forgotten - but it will work.

Edited by caminperth
caminperth Grand Master

caminperth

Posted
Posted
Also, will an R33 AFM work with a NEO computer?

If you're talking about an R33 turbo series 1.5 or 2 AFM then I think so. I've checked them against each other and they're the same plug.

Craved Grand Master

Craved

Posted
Posted
the R34s use the opposite to R33s in the clutch department so you may need to do some mods to make it fit.

ie if the R33 is push type the R34 is pull type....

Its been awhile since I changed clutch but I THINK its pull type for the R34....

i also beleive that the S1 and S2 use 2 different types of G/Box as well..

so the S2 might be the same as the R34.

DRFT 14 Collaborator

DRFT 14

Posted
  • Author
Posted
Nope - I'm saying a R33 RB25DET harness will plug into the NEO injector loom. Definitely right cause I'm driving around on it.. :)

Hmm, im kind of getting confused here guys. So the R33 loom fits a NEO motor? And caminperth, you also said a the R33 25t AFM and ECU both fit ? Others have said it doesnt, has anyone tried this themselves and can confirm for sure? If caminperth is right then my life will be much easier, NEO stuff is very rare compared to R33 25t parts (and much more expensive!).

Bluprint Veteran

Bluprint

Posted
Posted
What will plug in direct from R33DET gear:

Injectors - plug straight in

Are you sure?

While I've never played with the injectors on my car I've heard from just about everywhere that R33 injectors are side feed whereas R34 injectors are top feed.

Bluprint Veteran

Bluprint

Posted
Posted
R34 injectors are top feed? Interesting. Anyone know what they flow?

I think they flow something likw 320 or 340cc

I'm quite sure the 33 injectors flow more however, something like 370cc (shoot me down if I'm wrong)

but yeh, they are different

And likewise I have a Neo in my 31, PM me if you want to know anything

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • Waders360
      M35 Brake caliper replacement

      By Waders360 · Posted

      Hi from Canada, Both of my calipers are starting to fail. My car is a 2005 M35 Stagea ARX and I can't seem to find any parts or any cross reference caliper that would fit my car. Is there a company or a similar caliper that would fit and I could replace the OEM one. Or if anyone knows where I can find a new OEM. Any help is very appreciated. Let me know!
    • 25zenki
      S1 rb25/s14 starting problem

      By 25zenki · Posted

      Maf is a question mark but TPS  I have set at 0.47, the fact that I’m getting proper voltage range out of it with the key on leads me to believe it’s functioning properly. I’m getting proper voltages on basically everything. I still need to look up voltage ranges for z32 maf and test that 
    • 25zenki
      S1 rb25/s14 starting problem

      By 25zenki · Posted

      Honestly no not at all, but it’s a very basic tune, it’s stock injectors q45 tps and z32 maf. Other than that it’s a completely stock base map. The file is from nistune and from my understanding if it was tune related I would be able to unplug maf and tps and it would still start even if it was a really shitty start. I have tried starting it with coolant temp, maf, and tps unplugged none of those 3 togethor or individually changes anything 
    • Matt Z
      SAU NSW - Bathurst Run 2025

      By Matt Z · Posted

      🏆 Skyline Supremacy Meets Mount Panorama Magic 🏆 Join SAU NSW as we take the long way to Bathurst, the home of GTR greatness. Saturday 30th August 2025 7:00AM Meeting Hanna Park North Richmond 7:30AM Departure Cruise Via Bells of Line Road 9:00AM Arrival to Stop 1: Golden Poplars Meadow Flat 9:45AM Arrival to Final Destination: Mount Panorama Motor Racing Circuit Meet Location: Hanna Park North Richmond Stop 1: Golden Poplars Meadow Flat Final Destination: Mount Panorama Motor Racing Circuit   *Disclaimer* There will be a lead and follow car so no one should get lost. If you would like to attend or bring others along please put your name down and a +1 as numbers will be needed prior! This is NOT a race and we will all be adhering to all road rules. If this is what you want please come to one of our many track days. This is an official SAU:NSW event and will be run under a CAMS permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU NSW and thus, treat others accordingly. • Any misbehavior will not be tolerated and you will be asked to leave.
    • soviet_merlin
      My BMW E39 528i touring

      By soviet_merlin · Posted

      What does it look like with highway driving? And yes, I had a similar thought as Duncan. It looks quite similar in my Stagea and I have made myself accept it as normal. Might have to look into it some day   Highway gets as low as 10l/100km on my end so I'm not as worried about it being a mechanical issue. More likely just the tune on the haltech.
×
×
  • Create New...