Jump to content
SAU Community

RB25DET in GTS4 R32 conversion

Jim Boi

By Jim Boi,
in Engines & Forced Induction

 Share

Recommended Posts

Jim Boi Apprentice

Jim Boi

Posted
Posted
RB25DET in GTS4 R32 conversion

Hello all, 

As you can tell I'm new to this forum but have used it as a reference for many years and value the opinion and experience of the posters. 

I have recently purchased an R32 GTS4 and I'd like to swap the engine from a Stagea RB25DET Neo. I have read lots of posts on here and I've saved the pages so I should be able to get over some of the wiring issues. The mechanical side seems long and tedious and messy but as far as I can tell, reasonably straight forward. I have a few questions though:

Which ECU would suit the engine best, I've heard people favouring the RB20 ecu because it can be Nistune'd, Im thinking further down the line I will do this but I'm tempted to just use the ecu that comes with the engine? 

Are there any things to be aware of when doing this conversion, for example different years having different ecu pin outs etc?

Would it be quicker to install an earlier RB25DET (non Neo) to save some headaches later? - Is it an easier/quicker conversion?

I believe (don't quote me) that the full wiring and induction manifold and ecu can be used on the NEO engine, with some minor adjustments to fuel rails and idle control module (IACV) Is this more or less correct? 

 

I have recently restored an american muscle car and carried out a build log, I can start one for this car and upload it once completed as a guide or how to, if that suits or is required. 

Thanks in advance for any guidance. 

 

Link to comment
https://www.sau.com.au/forums/topic/470186-rb25det-in-gts4-r32-conversion/
Share on other sites
Guilt-Toy Grand Master

Guilt-Toy

Posted
Posted

You really need to buy a aftermarket ecu for this car.

Adaptronic modular ecu can do the awd and the vct.

I would not bother with the stagea ecu and the hassle you need to get it to run properly.

jmknights93 Mentor

jmknights93

Posted
Posted
1 hour ago, KiwiRS4T said:

Stagea Neo into GTS4 should be fairly straightforward...just have to make sure you use the same diff ratio front and rear. The hard part seems to be finding such an engine.

I have 2 of them at work. S2 RB25 and a RB25 NEO. Both AWD.

Jim Boi Apprentice

Jim Boi

Posted
  • Author
Posted

Thanks for the replies. I searched about last night and found a guide on putting in the non neo rb25 into an R32 Gtst. Is it similar wiring? 

By the looks of it, it may pay me to keep with the Neo ecu and get that Nistuned later on. 

Ive seen a few front cuts for sale, but in all honesty, I don't want to have to pull and engine out of a front cut - I'd prefer to just get the engine, turbo and loom to the ecu. 

 

 

jmknights93 Mentor

jmknights93

Posted
Posted
29 minutes ago, Jim Boi said:

Ive seen a few front cuts for sale, but in all honesty, I don't want to have to pull and engine out of a front cut - I'd prefer to just get the engine, turbo and loom to the ecu.

As per post above, I have 2 options available. PM me for details.

GTSBoy Grand Master

GTSBoy

Posted
Posted (edited)
6 hours ago, Jim Boi said:

By the looks of it, it may pay me to keep with the Neo ecu and get that Nistuned later on. 

 

You will need to Nistune it from the outset.  There are DTC faults that you can't deal with unless you have NIstune.  Missing ABS & TCS are the big ones.  Being able to override the boost sensor errors etc etc, also vital.

Edited by GTSBoy
GTSBoy Grand Master

GTSBoy

Posted
Posted

DTCs are fault codes.  Diagnostic Terminal Codes, or somesuch. The Neo era cars ABS computer talks to the ECU more than the R32 era cars' computers talk to each other, so I'd guess you'd be the same as not having ABS.  Actually making sure that your original ABS keeps working could be a challenge too.

Jim Boi Apprentice

Jim Boi

Posted
  • Author
Posted

Does the ecu talk to the abs then, I'm guessing there is an abs 'brain' somewhere? I was under the impression that the speed sensors for the abs were tied into the attesa ecu along with the g sensor under the centre console. 

Its look like a bit of a headache to use the neo engine. Perhaps the image of the neo ecu could be copied to the rb20 ecu - is nistune that advanced. 

What about an earlier Rb25det from a stagea, are these suitably strong enough for further tuning. I was biased toward the neo engine as I believed it would be more capable of taking the tuning. 

Again, thanks to all contributors, it's good to hear feedback. 

GTSBoy Grand Master

GTSBoy

Posted
Posted

There's no point in contemplating putting the Neo ECU's image into an RB20 ECU.  For one thing, it's just not possible.  For the another, it's the image/program that is the problem when it comes to expecting communications to/from other CUs in the car (ABS/TCS/ATTESA).  So it's not the type of ECU that matters. If you really wanted to you could run the Neo engine on an RB20 ECU with the RB20 image in there.  All you have to do is sort out the sensor wiring differences and tune it.  But that doesn't gain you anything at all.  You'd only do that if you were running some engine for which you cannot do Nistune into its ECU (like R33 and earlier Stagea engines).  So that also puts paid to your idea of using an earlier Stagea engine.  It wont make it easier, it will actually make it harder, because then you definitely have to use a non-native ECU to run the engine (if you want to tune it).

The Neo ECU is significantly more advanced than the older ECUs and therefore would be the better choice for running the engine.  If you Nistune it, then you obtain the ability to bypass all the DTCs that come up from not having proper communications between the other CUs.  And that's all you need to run the engine properly.

The ATTESA computer and the ABS computer in your car should still run just fine with a different ECU in there.  Look what happens to all the thousands of guys who put aftermarket ECUs into these cars.  The 4WD and brakes don't just suddenly stop working.  A Nistuned R34/Stagea ECU won't be any different.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted
On 28/04/2017 at 6:20 PM, Jim Boi said:

 

Its look like a bit of a headache to use the neo engine. Perhaps the image of the neo ecu could be copied to the rb20 ecu - is nistune that advanced. 

 

There is no headache if you use the appropriate ecu - a neo one from a S2 stagea or an R34 one. Try to get the engine, ecu and loom as a set and then  as GTSBoy says Nistune it - it has been done many times before. It doesn't matter whether its out of an auto or manual - it will work fine.

KiwiRS4T Grand Master

KiwiRS4T

Posted
Posted
1 hour ago, dr phil said:

Be wary of the diff ratios - i thought Stagea was 4.08 and gtr/gtst was 4.11. You may want to double check.

Quite right but wear on the tyres can make more difference than .03 in the ratio which is insignifcant.

  • 7 years later...
Jason Abell Newbie

Jason Abell

Posted
Posted

For anyone that comes here looking for answers on what can go wrong with gts-4 to rb25detneo swap. The Gloria's awd sump is different and does not fit. The rb25neo from stagea are exactly the same sump bolt pattern and axel alignment. Castings numbers are different on Gloria's blocks and oilpans if they need to be identified.

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

    • PranK
      New Skyline will be RWD and manual

      By PranK · Posted

    • GTSBoy
      Nismo GT Pro LSD configurations

      By GTSBoy · Posted

      No, you're wrong, and you've always been wrong about this. The Nismo has 2 sets of openings. One is a real 2-way, and the other is a 1-way. There is no 1.5-way possible with the ramps that they offer. A real 1.5-way does exist. That Cusco stuff I posted is a prime example. If the forward drive ramps are, say 55°, and the overrun ramps are, say, 30°, then you will get about half as much LSD effect on overrun than you do on drive. It is real, it realy works. OK, you're slightly right. The Nismo has 55° and 45° ramps on the 2-way, so it does offer less LSD effect on overrun. But, I think that just means that they've (probably) sensibly established that you do not want actually equal LSD effect on overrun. You just want "quite a lot, but not quite as much as the drive LSD effect".
    • DraftySquash
      Newbie from VIC

      By DraftySquash · Posted

      Just wanted to unearth this and post my baby with the new front ❤️😝 Took her to my wedding rehearsal today. Next up is getting wide skirts (after wedding)
    • Kinkstaah
      Nismo GT Pro LSD configurations

      By Kinkstaah · Posted

      Yea, that is what I was getting at in my ramblings too. The nismo one actually is a 1.5 way and a 1 way. They don't do a *2* way because a true *2* way would have equal ramp angles. Or is that a true 1.5 way? Realistically I think a "1.5 way" does not actually exist. A diff can either lock in two directions or one. It also doesn't help that a LOT of people in Australia speak about 1.5 way diffs are referring to their 1 way diff.
    • GTSBoy
      Nismo GT Pro LSD configurations

      By GTSBoy · Posted

      Well, the trouble with that ^^ is: The configuration shown is absolutely a 1-way, not a 1.5-way. There is no way that a 1.5-way can be said to offer LSD action only on acceleration. If Nismo cannot get that right, then it is impossible to believe their documentation. That ^ is not a 1.5 way setup. That is a 1-way.   And so now I have allowed all doubts to flourish and have gone back to look at the MotoIQ video. I originally made the mistake of believing him when he said "this is a 1.5-way" at the ~6:10 mark. Because what he did was take the gear assembly out of the 2-way opening and just rotate it one place to the left to drop it into the 1-way opening. When he dropped it in there, the cam was "backwards" compared to the correct orientation shown in all other photos of that config. The flat shold have been facing the 1° ramp side of the opening, not the 55° ramp side. And I thought, "gee that's cute", but I was concerned at the time, when he put the other ring back on, that the gap between the rings looked like it was wider then in the 2-way config. And then I said a lot of things in my long post on Tuesday that could only make sense if the guy from MotoIQ was correct about what he'd done. BUT... I have now done my homework. I grabbed a frame of the video with the 2-way config, and then grabbed another with the "1.5-way" config, snipped out the cam and opening of that frame and just pasted it direct on top of the 2-way config. I scaled it so that the triangular opening was almost exactly the same height in both. AND.... the gap between the plates is wider with the cam installed in the triangualr opening backwards. That is.... it cannot go together that way. There would be massive force on the plates all the time, if you could even reassemble it.  So, My statement on the matter? The Nismo diff is actually only a 2-way and 1-way. There is no 1.5-way option in it, regardless of what they say. Here's a photo of a real 1.5-way ramp opening from Cusco (along with the 1 way option). And the full set of 1 through 2 way options from their racing diff, which is not same-same as what we'd typically be using, but...the cams work the same. A little blurry, but it comes from this Cusco doc, which is quite helpful. AND.... Cusco do in fact do what I suggested would be sensible, which is to have rings that do 1 and 1.5, and 1.5 and 2. Separately.  
×
×
  • Create New...