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

[DatsunBanana]

Just plumbed in a Turbosmart boost gauge and I'm getting ~6 psi just using the stock R33 actuator that came on the turbo. I've disconnected all the hoses related to the inlet plenum butterfly (and disconnected its solenoid switch to be always open) so I can use the feed on the plenum for the boost gauge. I took out a bolt from the accelerator cable support in the bulkhead and fed a thin metal tube through that with hose connected each side. Quite pleased with myself about that cos the perfectly sized metal tube was an off-cut from the hard line that came attached to the R33 J-pipe that I used.

[lukeybrah]

Would be keen to see photos of how people have run and done their water feeds and return

[jap4lyf]

I used the DET intake manifold which has the fitting on the back for the water hose. And for the other one there is a water drain bung in the side of the block, I just pulled that out and got a fitting to screw in and used a braided hose onto the turbo. Pic is of the fitting in the block. Sorry haven't got anymore pics of it

[lukeybrah]

I used the DET intake manifold which has the fitting on the back for the water hose. And for the other one there is a water drain bung in the side of the block, I just pulled that out and got a fitting to screw in and used a braided hose onto the turbo. Pic is of the fitting in the block. Sorry haven't got anymore pics of it

That including the runners under neathe the plenum?

[jap4lyf]

Yep the whole manifold. Just used a new DET gasket and all bolted up easy as

[lukeybrah]

Yep the whole manifold. Just used a new DET gasket and all bolted up easy as

Spewing cause I just put new coolant in mine haha...

[DatsunBanana]

Same as Jap4lyf I have water feed off the coolant drain plug. You can see a close up pic of the fittings earlier in this thread. 1/4" BSPT to BSPP adaptor. 1/4" BSPP banjo bolt which was a good enough fit in the 14mm standard water line banjo and I just bent the line down a tiny bit to reach. For the return I also used a stock GTST return line round the back of the head then instead of the short rubber elbow into the back of the inlet manifold I ran a longer hose to a tee at the barb sticking up at the front of the stock NA inlet manifold.

Re-use the coolant if you drain it again. I had to do that with £100 worth of Evans waterless coolant :-)

Edited April 1, 2017 by DatsunBanana

[lukeybrah]

Same as Jap4lyf I have water feed off the coolant drain plug. You can see a close up pic of the fittings earlier in this thread. 1/4" BSPT to BSPP adaptor. 1/4" BSPP banjo bolt which was a good enough fit in the 14mm standard water line banjo and I just bent the line down a tiny bit to reach. For the return I also used a stock GTST return line round the back of the head then instead of the short rubber elbow into the back of the inlet manifold I ran a longer hose to a tee at the barb sticking up at the front of the stock NA inlet manifold.
Re-use the coolant if you drain it again. I had to do that with £100 worth of Evans waterless coolant :-)

Great info thanks! What exactly is that return connecting to?

[DatsunBanana]

This pic is a bit dark but you can see the tee in the circle. At the front of the stock NA inlet there's a vertical hose connector with a hose coming up and across to the aac valve. I teed into that hose and took a hose to the turbo water return hard line coming round the back of the block. I took a chance as no-one could confirm what the water flow was like inside the DET inlet but all up and running and my water temperatures are good.

[DatsunBanana]

A bit more to my story ... I've tricked the ECU into turning off the engine management light. As per other threads elsewhere on here (e.g. secret squirrel trick) I used a few diodes soldered in series and took off various voltages by soldering wires at different points in the chain to feed into relevant ECU pins. I got more or less correct voltages into pin 47 (my yellow wire in the pic ~2.6V) and pin 51 (my orange wire ~3.4V). For pin 53 (my orange/black striped wire) I managed to get about 4V but I'm not entirely sure if that's enough for the 4.7V expected by that pin (according to service manual) or maybe that missing pin signal wasn't contributing to my error codes in the first place.

I had thought about getting some spare pins for the ECU harness and making a more robust job of it but in the end I just stripped a few mm of insulation off my wires from the diodes and poked them through the correct holes at the back of the ECU plug. (if the bare wire poked out the other side I trimmed it). Pic gives an idea of what it looks like in place. The red wire to pin 48 provided +5V to my diodes and the black wire from the ground of my circuit went into pin 43. I just jammed these two wires in as far as I could against the pin that was already there on the NA harness. The series of diodes is wrapped up in plenty of heat shrink sleeve as you can see. It all tucks in neatly once I clipped the ECU plug cover back on. In fairness a good tug would pull all the wires out but it's all covered by the kick panel so I'm not too worried about that.

If I get a minute I'll draw a circuit diagram and post it.

[Amghugs]

hey guys

 

I’ve just picked up a impul ecu for my rb25de turbo conversation..

I’ve got the check engine light on and I’m pretty sure it’s because of the boost pressure sensor.. and most likely other sensors, 

 can someone please help me with either finding how to do the squirrel trick, to trick the ecu that everything is running fine..

apparently you just use pin 48, it's the 5 volt reference supply for all 3 sensors 

but I have no idea what I’m doing, can someone put me in the right direction please or send me to a guide or some diagrams etc

  

[Dil-Dog]

@hey_aleks @DatsunBanana Hey guys i would like to say thank you very much for documenting your works and helping people like me trying to do the same! but i DESPERATELY need help... I dont understand what to do with the intake plenum, i see that you started out with r33 plenum but my question is why did you switch it up and then used the throttle body of the NA one but still on the r33 intake?  and how does it work on DE NEO head if the intake ports on the block are different? Please answer soon! ?Can you please tell me exactly what to do and what needs to go where? 

[Dil-Dog]

@hey_aleks @DatsunBanana basically asking for further explanation and guidance on the intake manifold because i have both r33 and DE neo for my NA 1998 R34 skyline and i am leaning more towards using the turbo r33 intake because of the larger runners and the simplicity over the confusing and dumb y intake with "butterfly" and its issues and wiring. 

[KiwiRS4T]

On 7/31/2019 at 6:47 AM, Dil-Dog said:

@hey_aleks @DatsunBanana basically asking for further explanation and guidance on the intake manifold because i have both r33 and DE neo for my NA 1998 R34 skyline and i am leaning more towards using the turbo r33 intake because of the larger runners and the simplicity over the confusing and dumb y intake with "butterfly" and its issues and wiring. 

Just use all of the RB25DET

[DatsunBanana]

I think like Kiwi says if you have the R33 stuff you may as well use all that but I think the throttle body electrical plugs might be different which is why you'd use the R34 one. Someone will correct me if I'm wrong. 

The R33 turbo plenum has some advantages ... ports are bigger although I don't remember if the DE head ports match that size. Good thing is it will have a water return hose fitting on the back and I would imagine it's easier to get at spark plugs and coil packs when you don't have to remove the y-pipe every time. Plus if you're changing injectors you have to take it all off anyway so may aswell change it.

Having said that I just kept the R34 y-pipe and disabled the butterfly. It closes with vacuum pressure so when disconnected it will open up the plenum anyway. 

[DatsunBanana]

On 27/07/2019 at 8:29 AM, Amghugs said:

 can someone please help me with either finding how to do the squirrel trick, to trick the ecu that everything is running fine..

Did you get this sorted? If not I'll try and remember exactly what I did ?

[hugh jaynous]

On 27/07/2019 at 12:29 AM, Amghugs said:

hey guys

 

I’ve just picked up a impul ecu for my rb25de turbo conversation..

I’ve got the check engine light on and I’m pretty sure it’s because of the boost pressure sensor.. and most likely other sensors, 

 can someone please help me with either finding how to do the squirrel trick, to trick the ecu that everything is running fine..

apparently you just use pin 48, it's the 5 volt reference supply for all 3 sensors 

but I have no idea what I’m doing, can someone put me in the right direction please or send me to a guide or some diagrams etc

  

that's a decent thread to reference for the "squirrel" trick, it's taking that reference pin and supplying the 5v source to the 3 other pins. The diodes roughly drop the voltage about .6v per diode so just roughly do the math listed in the thread to get the output you need for each pin.

[Dil-Dog]

Hello everyone

HELP

 i am currently converting my r34 GT rb25de NEO to now become turbo charged....now i have a couple of questions for you guys that i hope you can help me with. 

#1 Is it possible to use a complete stock r33 turbo intake? or a fredyy/greddy? ( I HAVE BOTH)

#2 Can it be done using stock NA/DE engine Harness?

Lastly i Have  a Turbo R34 GTT Ecu to run it all.

THANKS! ADVICE IS URGENTLY NEEDED

[Rusty Nuts]

1 hour ago, Dil-Dog said:

#1 Is it possible to use a complete stock r33 turbo intake? or a fredyy/greddy? ( I HAVE BOTH)

The DE NEO intake ports are at least 3mm narrower (smaller)all round and the fuel injector shrouding is completely different. If you are happy with these mismatches the parts will physically fit together.

Edited September 5, 2019 by Rusty Nuts

[Rusty Nuts]

2 hours ago, Dil-Dog said:

#2 Can it be done using stock NA/DE engine Harness?

Lastly i Have  a Turbo R34 GTT Ecu to run it all.

This has been discussed AD NAUSEUM in the last 6 pages mate, you could at least read them.

(Ad nauseam is a Latin term for argument or other discussion that has continued to the point of nausea. For example, "this has been discussed ad nauseam" indicates that the topic has been discussed extensively and those involved have grown sick of it.)

Edited September 5, 2019 by Rusty Nuts