Doing a +t conversion on an unopened RB25DE NEO (R34 GT)

[Dil-Dog]

thanks, rusty balls

[DatsunBanana]

Here's a summary from my experience and from the other guys who posted in this thread - and before that from reading 666Dan's legendary thread (many times) and others on this subject. I know it's a lot to take in and I remember that I still had a few questions I just needed some reassurance on.

Assuming you've put GTT injectors on, you can run a standard GTT manual ECU (it'll work on the auto or manual). You can always nistune it later but until then keep the boost at actuator pressure - about 6-7 psi.

If you use the standard R34 DE Y-pipe inlet, disconnect the butterfly valve plug cos the GTT ECU will send different signals on that pin. You'll have to tee into the pipes somewhere for the turbo water return and you'll have to make some custom j-pipe solution. I've done this without changing the loom at all.

If you want to try the R33 inlet you need to search for what to do about the throttle body and idle control plugs as pretty sure there is some difference. That's where loom changes might be needed but maybe not if you swap the correct R34 parts onto the R33 inlet. You won't have to tee into pipes for water return cos its on the back of the inlet. There's nothing for the butterfly plug to connect to so leave it loose. All the standard R33 IC and inlet piping should fit so no custom work for that. The larger ports on the plenum will meet a restriction against the smaller NEO DE head ports but my opinion is that who cares about airflow not being perfect when you've just gained a load of boost.

If you want to use the Greddy/Freddy I think that's a lot of work anyway even doing it to a standard turbo car so probably even more research needed there. Loom changes might be needed for this but not entirely sure.

[Rusty Nuts]

42 minutes ago, Dil-Dog said:

thanks, rusty balls

Yeh I've earned them. You just want short cuts "oxygen thief"

Edited September 5, 2019 by Rusty Nuts

[Patrik 34]

Hey guys I would like to start buying parts and slowly building my na+t conversion only thing is I have no clue how much it would cost me I own a mechanical workshop so Labor price doesn't concern me but the cost of all the parts and time to do it is something I would like to know before I start. If anyone can give me a rough estimate that would be appreciated

[GTSBoy]

About $20k for a nice GT-T.

[Cohen_davis]

Ok Bois having some issues with this conversion at the moment, plz help

All the turbo gear is in and plumbed up 

DET neo injectors 

Starts and Runs great on the DE ecu (bit rich on idle because DET injectors obviously) 

Purchased a DET neo ecu with nistune installed, tuned for all stock parts just 10 psi and its hard to start and runs lean,

 Is there any difference in the wiring that needs to be addressed ? 

Thanks for any help 

[Dose Pipe Sutututu]

1 hour ago, Cohen_davis said:

Ok Bois having some issues with this conversion at the moment, plz help

All the turbo gear is in and plumbed up 

DET neo injectors 

Starts and Runs great on the DE ecu (bit rich on idle because DET injectors obviously) 

Purchased a DET neo ecu with nistune installed, tuned for all stock parts just 10 psi and its hard to start and runs lean,

 Is there any difference in the wiring that needs to be addressed ? 

Thanks for any help 

Tuner related problem

[Cohen_davis]

1 minute ago, Dose Pipe Sutututu said:

Tuner related problem

Yea I was thinking the same thing, 

I'm running all the stock DE intake, AFM and TB with just the DET injectors, that's no issues? 

I haven't had it tuned yet, was just advised it was stock 25det neo with 10 psi 

Do you know if there's Any way of reverting back to stock base image or disable the nistune type 4 board ? 

 

[Dil-Dog]

Yeah fam you aint got a problem with wiring harness... however check pages 5&6 to see the actuall differences in the pin outs and how it can be possible to clear your check engine light. 

If its a pink labeled NEO afm then its no difference between the turbo and non turbo... they share the same part number.

Maybe you should turn down your boost for a bit, running lean is very bad

i’ve done my de+t neo, so if you need any other help or advice holla at yuh boi 

Edited December 19, 2019 by Dil-Dog

[Dose Pipe Sutututu]

7 minutes ago, Cohen_davis said:

Do you know if there's Any way of reverting back to stock base image or disable the nistune type 4 board ?

You'll need the PLMS cable & Nistune suite to do that

[Cohen_davis]

1 minute ago, Dil-Dog said:

Yeah fam you aint got a problem with wiring harness... however check pages 5&6 to see the actuall differences in the pin outs and how it can be possible to clear your check engine light. 

If its a pink labeled NEO afm then its no difference between the turbo and non turbo... they share the same part number.

i’ve done my de+t neo, so if you need help, holla at yuh boi 

Cheers bud, yeah pink labels AFM and all the works the swap has been done reasonably cleanly, yeah I cant see the CEL because it's a neo swap into an r32 which presents more headaches in itself ?.  I never did the neo DE swap (was like that when I purchased it) but I'm doing the +T because I had all the bits laying around ?

[Cohen_davis]

5 minutes ago, Dose Pipe Sutututu said:

You'll need the PLMS cable & Nistune suite to do that

Yeah I thought so, I'll leave it with the tuner to sort out I think ?

[Gojira34]

Hey, I’ve only read a page of this thread!

but I was always under the understanding that Auto Det’s neo Ecu’s can’t run a nistune, as they don’t have shift logic!??, they can use piggy back to control fueling etc...

an auto ecu will run a manual, therefore can run nistune!

on the topic of the nistune ecu tuned to run 10psi! I would get it tuned quick! 

my 34 neo auto runs 10psi on stock tune because it has  3” exhaust! No back pressure! No other mods that I know off. It did come straight from Japan to dealer to me! So it may have had a tune?? But don’t think so!

Also gets 10 psi at ~3000rpm as 2stageboost is grounded!

 

[GTSBoy]

31 minutes ago, Gojira34 said:

under the understanding that Auto Det’s neo Ecu’s

No. The TCU is in the ECU. They accept Nistune just fine and can continue to run an auto or a manual engine with no troubles.

What you are thinking of is certain combos of autos with separate TCUs and PowerFCs.

[hugh jaynous]

12 hours ago, Gojira34 said:

Auto Det’s neo Ecu’s can’t run a nistune, as they don’t have shift logic!??

GTSboy is correct, the shift logic should make no difference if your vehicle is already a GTT from the sounds of it. The shift logic is seperate in the auto NA ecu vs the GTT auto ecu which is together. From what others have said it makes more headaches for the NA auto ecu > +t with Auto GTT ecu and nistune as there would be two shift control units in the car.

[Kinkstaah]

Correct, this issue happens because

1) The NA Auto ECU cannot accept a Nistune
2) A GTT Auto ECU cannot natively run the Auto gearbox from the NA car, because the NA car has a seperate TCU.

You can wire the the inputs to the NA TCU into the GTT ECU on the correct pins and bypass the NA Auto TCU. Nissan have the wiring diagrams of both units available in the shop manual.

This has only been done successfully a couple of times. It isn't that hard, about ~20 wires. All clearly labelled in the shop manual. People just never tried it, or had need to.

[Gojira34]

On 15/08/2020 at 2:06 PM, GTSBoy said:

No. The TCU is in the ECU. They accept Nistune just fine and can continue to run an auto or a manual engine with no troubles.

What you are thinking of is certain combos of autos with separate TCUs and PowerFCs.

Yes the Auto ecu is in the main ecu, that’s why I thought the nistune can’t control it, too complicated!

whereas in other models the auto ecu is seperate, so it just control the tranny as normal Operation and main ecu runs the engine?!

 

this is what I always thought, was told by many and read too, even the nistune website says only manual! Maybe I misread! Hmmm

Guess I didn’t have to convert to manual! Lol

thanks for the info!

Edited August 29, 2020 by Gojira34

[R34Nur]

I've done a DE+T conversion on my auto R34 and didn't change anything on the wiring for the auto box.  I just fitted a GT-t ECU from an auto car and it works perfectly, including the tiptronic. 

 

[Kinkstaah]

11 hours ago, R34Nur said:

I've done a DE+T conversion on my auto R34 and didn't change anything on the wiring for the auto box.  I just fitted a GT-t ECU from an auto car and it works perfectly, including the tiptronic. 

 

This is because the new ECU is not driving the gearbox, and your NA gearbox is being driven by the NA gearbox ecu. (which is not the part you changed)

[DarkGodV]

Hi,

Im scrolling these pages trying to find a definite answer but im still not 100% sure...

I have a Manual converted 95 R33 with a 20e in it.

I Have healthy 25de neo engine with ecu & loom, out of an auto 2000 R34 GT currently on an engine stand.

Im looking at buying all turbo components including ecu, off a C35 Laurel, with a auto 25det neo.

If I was to put all components on my 25de, could I run the 25DET ecu and daily drive it, or would I have to get a piggyback $ tune.

Edited September 20, 2021 by DarkGodV