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

[hey_aleks]

Yeah basically ended up finishing all the big parts. Car drives great now, I do still have the check engine light though. Since I used the GTT intake system, my traction control and throttle motor sensor units are throwing faults (maybe because I'm still using the n/a ones with the turbo ecu). However this doesn't effect how the car drives.

I've been doing test runs to see if anything leaks or overheats but it all looks good. Car just has boost in every gear and after owning many R33s, feels much snappier and drives differently to normal turbo engines. Still yet to get it tuned but at-least I am able to monitor everything through nistune so no damage can be caused.

Awesome that you were able to pick up a front mount as well as the other parts, it's a big thing to get out of the way. I'd say my front mount inter-cooler was one of the toughest parts of the conversion. Getting it to clear the radiator fan while the bonnet was fully closed took a good day (I did end up just cutting the fan blades with a hack saw equally). I had to drill a hole next to the battery for the cool side of the fmic. A bit of custom work might be needed but you'll be fine.

I'm going to start my brake conversion soon since you can definitely feel the n/a brakes being the weak point atm and also a tyre upgrade all around.

[hugh jaynous]

Just wondering what were the dimensions of the FMIC that you grabbed? and did you have to do any reo bar cutting?

[hey_aleks]

Not too sure on the dimensions mate but it looks to be fairly standard compared to my previous ones. I did end up cutting the reo bar but I'm pretty sure if you really wanted to, you could avoid doing so. There are some guides on the internet and maybe look at getting a return flow fmic? This removes the need to possibly relocate the battery or cut holes on the left side of the chasis.

[hugh jaynous]

I see, another question regarding the ecu. So you got the gtt ecu, nistuned it and then you got the shop to wire up to the existing 25gt loom? Or did you also bring in a gtt loom to mate to the gtt ecu,  replacing both the stock gt ecu and loom.

[hey_aleks]

All I did was just buy a GTT auto ecu with nistune already installed on it. You can either do that or just buy a GTT auto ecu and the nistune separately and either solder it on yourself or get someone to do it. The ecu part of the loom is exactly the same with the GT and GTT cars so it was plug and play. In Adelaide, most tuning shops do a combo where they install nistune on either your ECU or one of theirs and dyno tune your car for around $900-$1000 so probs best to ring a few and see what they think before buying anything. What state do you live in mate?

[hugh jaynous]

Would be too easy if that were possible, I live in Canada where my 98 skyline has only been legal for about 3 years. I'd have to likely find the ecu and solder myself then take to a shop to get them to dyno it.

[hey_aleks]

Yeah I think doing It yourself is the better option as some people charge like $100 just to solder it. As for the tuning, fuel doesn't need to be altered just ignition timing so as long as they're a decently reputable tuner, they'd be able to sort you out. Nistune is very basic, just ring a few shops that you can find and explain the situation. They might even have another option for a piggy back.

[hugh jaynous]

Most shops rang here said to go nistune route since it's the most friendly to piggy back vs the other option of emanage of which they completely told me don't do because they don't like it. My timing when I baseline dynoed it, was said to have been retarded already to compensate for lower octane fuel in North America, so I'm not even sure if I'd have to adjust that too far if at all to get it to a shop. Thanks for the replies, definitely need to prep for this as much as possible since I would need to finish this in about 4 days time so planning everything is a must. 

[hey_aleks]

Yeah if you need to be done in 4 days I reckon start asap mate, never know what will come up when doing the conversion. I don't think a fmic is necessary if Canada doesn't get really hot so you could stick with an r33/34 smic but not sure what your plans are. Reply with all the parts you're using just so I can go over them and see what issues I had when putting my parts on. Also I'm getting my first tune done next week (been using the det ecu so far and it runs completely fine with some timing pulled back). I tecommend maybe looking into an e85 tune if you're getting a compatible fuel pump and 1000cc+ injectors. Otherwise just go with the stock parts, you'll definitely be happy with the power if all goes well mate.

[hugh jaynous]

Ah I mean to say I want to finish this job over 4 days when it comes to doing it, will be a bit before I gather all the parts needed. Looking to get around the 210kw range or so and currently only have

Injectors, oil feed tee, walboro pump, and exhaust manifold.

So still missing the ecu, turbo, turbo lines, intercooler, piping, and a well lit garage.

I will be keeping the twin intake, fair bit of custom tubing to be fabbed or bought. The exhaust piping I will be getting customed as well from a local shop who specialize in exhausts and have excellent warranties against damages. As for the tune I'd like to even get it to just run our basic 94 pump gas before hitting up e85 as that's scarce beyond scarce here.

I've done some maintenance on the engine before so taking it apart isn't my first time so I'm hoping that helps to keep everything within the 4 day time span. 

Edited October 13, 2016 by hugh jaynous

[DatsunBanana]

For your intercooler did you have to bring one of the pipes up through the body work by the expansion bottle? (where there are 2 already there on a GTT). Do you remember what size hole you cut? I need to get a hole saw and do that sooner rather than later for a test fit of my intercooler when that arrives.

[hey_aleks]

Ah I mean to say I want to finish this job over 4 days when it comes to doing it, will be a bit before I gather all the parts needed. Looking to get around the 210kw range or so and currently only have
Injectors, oil feed tee, walboro pump, and exhaust manifold.
So still missing the ecu, turbo, turbo lines, intercooler, piping, and a well lit garage.
I will be keeping the twin intake, fair bit of custom tubing to be fabbed or bought. The exhaust piping I will be getting customed as well from a local shop who specialize in exhausts and have excellent warranties against damages. As for the tune I'd like to even get it to just run our basic 94 pump gas before hitting up e85 as that's scarce beyond scarce here.
I've done some maintenance on the engine before so taking it apart isn't my first time so I'm hoping that helps to keep everything within the 4 day time span. 

Looks like you've got most of it sorted out [emoji106]. Probably don't need too much lighting as long as you have some portable lighting as well. Maybe it wouldn't be a bad idea to get the engine compression tested before the conversion to make sure it'll be 100% worth?

[hey_aleks]

For your intercooler did you have to bring one of the pipes up through the body work by the expansion bottle? (where there are 2 already there on a GTT). Do you remember what size hole you cut? I need to get a hole saw and do that sooner rather than later for a test fit of my intercooler when that arrives.

So there was already a circle on the passenger side of my engine bay so I used that. For the other side, I had to remove the windscreen bottle to move the battery over and cut a hole using an angle grinder so there was no size. I'll send a picture in a bit when I get to my car [emoji106]

[jap4lyf]

Hey guys! Awesome thread, glad to see there's a decent na+t guide for r34s now. 

I have been slowly collecting parts for about 12 months now getting ready to do the conversion, just have 1 question regarding the intake manifold. I have been told that na neo heads have much smaller intake ports and that the DET neo intake manifold holes don't line up probably. Can anyone confirm this? Can you just leave the intake runners on and swap over the top half? Not keen on running the y pipe over the motor. 

Thanks in advance

[hugh jaynous]

19 hours ago, jap4lyf said:

Hey guys! Awesome thread, glad to see there's a decent na+t guide for r34s now. 

I have been slowly collecting parts for about 12 months now getting ready to do the conversion, just have 1 question regarding the intake manifold. I have been told that na neo heads have much smaller intake ports and that the DET neo intake manifold holes don't line up probably. Can anyone confirm this? Can you just leave the intake runners on and swap over the top half? Not keen on running the y pipe over the motor. 

Thanks in advance

Photo with the two intakes is NEO NA on top and RB25DET from an R33 on bottom. The second photo with the gasket is the det gasket over the neo. Looks like it lines up pretty well for every bolt, but that's pretty much all I've got from searching around. 

[hugh jaynous]

Where as running the single entry pipe in I'm not sure what aleks did to get it to run, but that would definitely be alot easier for coil and spark maintenance. 

[DatsunBanana]

I'm planning to keep my Y pipe. It is extra work to change plugs/coilpacks but after a couple of times it's not so bad. I guess there's some advantage in the DET inlet especially to put the standard BOV and turbo water return on. Not sure if the poorly matched large manifold ports meeting the smaller head ports might have some effect on the smooth flow of air but hey, bolting a turbo on is gonna be better than it was right? Interesting points about the Y pipe from Dan in the thread here - it's tempting to try what he said about that butterfly valve ...

Did this today ... attacked the front bumper and got the reo bar off ready for cutting for the FMIC which should arrive in the next couple of days. Want to have a go at the rust spots as well.

In the second pic, I don't know what the plastic thing is or where it came from. It was on the floor after removing the bumper. Aleks did you come across one when removing your bumper?

[hey_aleks]

Hey boys, not too sure what that piece is mate but I remember chucking a few useless pieces after removing my bumper since it didn't look like they had a purpose. 

This is what my setup looks like right now:

-no bov

-coolant feed line from the manifold has been blocked off since I'm already using the heater core

-using the piece at the end of the GT y-piece as my throttle body (since the tps plugs are different on the gtt throttle body and our loom will only plug into the GT tps)

-also have added a nipple after the Turbo elbow to support a boost controller which goes to the waste gate 

Just an update guys, there are a few fault codes which will probably have to get fixed by a tuner. The abs system and boost sensor pressure codes won't clear my ecu as the 34 has a boost pressure sensor on the cross over pipe where as I've tried the 33 one and the custom one I have on now. I do know for certain that the ecu is cutting power as the timing is all over the place so it is definitely a good idea to get is looked at by a tuner. However, I've gone on a few 2-3 hour drives (hitting boost non stop since im a chile) while also dailying the car and clocked 2000 kms and the car runs nicely. It does however idle high since the gtt manifold has a different cold start system but this can be resolved by a tuner maybe using a GT base image instead of a gtt one? In drive (auto for the time being), the car idles perfectly. Next thing to do is upgrade injectors, get it tuned on e85 for reliability and bloody install an lsd (single wheel burnouts are disgusting)

 

 

[hugh jaynous]

Another question on how the cars running aleks, does the nistune chipped ecu let you use the TIPTRONIC controls still? or have you strictly been using it only in auto? I would be a little sad to see some downshifting exhaust popping going away haha.

[hey_aleks]

Nah I only ever drive it in triptronic it definitely still works  I'd die if it was just auto