Jump to content
SAU Community

rb25 engine and trans swap work but without the tcm?

romel

By romel,
in R Series (R30, R31, R32, R33, R34)

 Share

Recommended Posts

romel Apprentice

romel

Posted
Posted
Hii all,
 
I am doing a rb25de neo engine and transmission swap on my r34 but wanna keep the rb20de harness so i spliced and joint the transmission cables(speed sensor, park neutral switch and solenoids) where needed cause the rb20 wiring is ecm.tcm 
i already found an rb25 ecu with ecm tcm in one instead of separate cause my rb20 setup was ecm tcm. The rb25 transmission has an turbine sensor , does the turbine sensor need to be connected or can i just leave it disconnected?
 
Are there any issues that i will run into with you the setup?
Kinkstaah Grand Master

Kinkstaah

Posted
Posted

This may not be the right place to say it, but the RB25NEO N/A is actually ecm with seperate TCM as well.

Those inputs are incorporated cleanly into the R34 GTT from memory (according to my memory of the workshop manual). In short, if you have the correct RB25NEO ecu, it won't have any provisions for transmissions. If you have the RB25NEO DET ECU, it should have them all.

... if it's an auto ECU.

romel Apprentice

romel

Posted
  • Author
Posted
11 hours ago, Kinkstaah said:

This may not be the right place to say it, but the RB25NEO N/A is actually ecm with seperate TCM as well.

Those inputs are incorporated cleanly into the R34 GTT from memory (according to my memory of the workshop manual). In short, if you have the correct RB25NEO ecu, it won't have any provisions for transmissions. If you have the RB25NEO DET ECU, it should have them all.

... if it's an auto ECU.

The ecu i was going to connect to the setup is a 23740-0V010 ecu of a stagea that has ecm and tcm in one

Kinkstaah Grand Master

Kinkstaah

Posted
Posted

Right, so that is the same (or very similar, I'm not sure how similar) to the GTT ECU.

I only looked at this for 15 minutes about a decade ago, but from what I remember, all of the sensors/wires/pins for the R34 N/A TCM existed on the R34 GTT main ECU. Basically the only difference between the GTT auto and GTT manual ECU was the addition of those pins, which perfectly mapped to the TCU's pins in the NA car.

This was followed by a lot of me screaming why a workshop could not have figured this out in the 3 years they had previously had the car. It's possible there's some other complication..

In my example I had a standalone transmission ECU, which I wired into following the diagrams and everything worked fine. I found other posts that people had wired the NA Autobox into the GTT ECU without issue, and after looking at the diagrams I understood why there was no obvious writeup for it. I ASSUME.

romel Apprentice

romel

Posted
  • Author
Posted
18 hours ago, Kinkstaah said:

Right, so that is the same (or very similar, I'm not sure how similar) to the GTT ECU.

I only looked at this for 15 minutes about a decade ago, but from what I remember, all of the sensors/wires/pins for the R34 N/A TCM existed on the R34 GTT main ECU. Basically the only difference between the GTT auto and GTT manual ECU was the addition of those pins, which perfectly mapped to the TCU's pins in the NA car.

This was followed by a lot of me screaming why a workshop could not have figured this out in the 3 years they had previously had the car. It's possible there's some other complication..

In my example I had a standalone transmission ECU, which I wired into following the diagrams and everything worked fine. I found other posts that people had wired the NA Autobox into the GTT ECU without issue, and after looking at the diagrams I understood why there was no obvious writeup for it. I ASSUME.

I guess i should just give it a try and see what complications i het allong the way?

Kinkstaah Grand Master

Kinkstaah

Posted
Posted

I know you're in Surname, so parts availability could be pretty fkin weird. If it were me I would be trying to get the correct engine ECU/TCM (integrated or otherwise) for the engine itself. There's not always a lot of wriggle room for when it doesn't work, as it'll just flat out not work.

That said what you have is pretty close, a RB25NEO with a Stagea ECU (... gtt?) but there's still some pretty big differences between the turbo stag motor and the RB25NEO Non turbo.

So it'll either be great or really damn annoying depending on how well you study diagrams and how well Nissan lego decides to fit together in the real world.

romel Apprentice

romel

Posted
  • Author
Posted

So a small update,

i continued with using the RB20 wiring on the RB25 trans and engine and the car runs good but i have to drive the car under 3000rpm otherwise its being rev limited and doesn't want to shift to another gear, i removed the ABS fuse and shifting went smoothly only thing is the KM and ABS doesn't work but i wasn't being limited till 3000rpm. 

So are their possibilities that the speed sensor 2 is creating issues?

and does anyone know where its located cause the RB25 trans has nothing on the tail like the C35 Laurel. 

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

    • Duncan
      Mistakes were made, my R34 Story

      By Duncan · Posted

      Have a look at that (shitty) pic I posted. You can see AN -4 braided line coming to a -4 to 1/8 BSPT adapter, into a 1/8 BSPT T piece. The Haltech pressure sender is screwed into the long arm of the sender and factory sender (pre your pic) into the T side. You can also see the cable tie holding the whole contraption in place. Is it better than mounting the sender direct to your engine fitting......yes because it removes that vibration as the engine revs out 50 times every lap and that factory sender is pretty big. Is it necessary for you......well I've got no idea, I just don't like something important failing twice so over-engineer it to the moon!
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      Yup. You can get creative and make a sort of "bracket" with cable ties. Put 2 around the sender with a third passing underneath them strapped down against the sender. Then that third one is able to be passed through some hole at right angles to the orientation of the sender. Or some variation on the theme. Yes.... ummm, with caveats? I mean, the sender is BSP and you would likely have AN stuff on the hose, so yes, there would be the adapter you mention. But the block end will either be 1/8 NPT if that thread is still OK in there, or you can drill and tap it out to 1/4 BSP or NPT and use appropriate adapter there. As it stands, your mention of 1/8 BSPT male seems... wrong for the 1/8 NPT female it has to go into. The hose will be better, because even with the bush, the mass of the sender will be "hanging" off a hard threaded connection and will add some stress/strain to that. It might fail in the future. The hose eliminates almost all such risk - but adds in several more threaded connections to leak from! It really should be tapered, but it looks very long in that photo with no taper visible. If you have it in hand you should be able to see if it tapered or not. There technically is no possibility of a mechanical seal with a parallel male in a parallel female, so it is hard to believe that it is parallel male, but weirder things have happened. Maybe it's meant to seat on some surface when screwed in on the original installation? Anyway, at that thread size, parallel in parallel, with tape and goop, will seal just fine.
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      How do you propose I cable tie this: To something securely? Is it really just a case of finding a couple of holes and ziptying it there so it never goes flying or starts dangling around, more or less? Then run a 1/8 BSP Female to [hose adapter of choice?/AN?] and then the opposing fitting at the bush-into-oil-block end? being the hose-into-realistically likely a 1/8 BSPT male) Is this going to provide any real benefit over using a stainless/steel 1/4 to 1/8 BSPT reducing bush? I am making the assumption the OEM sender is BSPT not BSPP/BSP
    • funkymonkey
      Jacks that fit under GTR lips that can reach the subframe?

      By funkymonkey · Posted

      I fashioned a ramp out of a couple of pieces of 140x35 lumber, to get the bumper up slightly, and then one of these is what I use
    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      I wouldn't worry about dissimilar metal corrosion, should you just buy/make a steel replacement. There will be thread tape and sealant compound between the metals. The few little spots where they touch each other will be deep inside the joint, unable to get wet. And the alloy block is much much larger than a small steel fitting, so there is plenty of "sacrificial" capacity there. Any bush you put in there will be dissimilar anyway. Either steel or brass. Maybe stainless. All of them are different to the other parts in the chain. But what I said above still applies.
×
×
  • Create New...