New R32 Owner in USA

[bakwoods]

Hey guys, I know this is an AUS forum however I'm not having any luck with support in the US for the Skyline, in fact the Nismo guys are less than helpful and rude to boot. 

Purchased a 1990 Skyline GXi chassis (FR serial number) with an RB20DET swapped into it. It was a real mess wiring wise. I'm still trying undo the damage done. The car is an A/T which is good for me since I'm a cripple. I won't lie, I'd love a 5 speed, but it's hard to shift with my condition.

Fast forward to a week ago, I took the car off the road, took the entire interior out (carpet included) and I started figuring out where to begin. I yanked out the entire chassis harness and TCM, it was a nightmare and when I download the pics from my phone I'll share the build. It wasn't pretty. It was rat's nest of wires under the engine fuse box and even bigger mess near the ECU. Somehow an R31 ECU was hard wired into the harness to work. 

I found a new chassis harness off of a GTS-T which was A/T and came with a new TCM for $200. Sweet deal and when I got it, it was unmolested! How rare is that? I ran the fuse box, I ran the entire chassis harness from the dash back to the tail lamps. Everything looks good. Even came with the Clarion amp and wiring (it'll be removed). Even had the EGT probe for under the passenger side seat, again, something mine didn't have. 

It took me a 2 days to realize that the engine harness was a separate assembly and I needed to buy that in addition to. So I ordered it and it's on its way now from Japan, $300 later. So now I'm $500 in on wiring but it'll eliminate a lot of issues. I'm assuming the engine harness has the wiring for the alternator and starter unless that's somehow a separate unit? Shouldn't be (hopefully)

Halfway into my dimwitted effort to replace the harnesses I decided "Hey let's order an RB25DET NEO with A/T trans." Found one from a reputable source in Canada for $1,700 shipped. 

So now my big question is what is it going to take to get the 25 motor to work with the 20 harness. I've spent about a week searching and found the general details like swapping two injector wires on the RB20 ECU and RB20 harness when installing the 25 motor. Though the transmission is what eludes me. 

I haven't found any posts, threads, information pertaining to running an RB25 auto trans on a RB20 harness. From my understanding the RB25 ECU controls both transmission and engine. If that's the case then what's my next step to make it work? Should I just try to find an RB25 auto chassis and engine harness and scrap everything? 

 

[GH05T]

32gxi, thats rare.
getting the 25 while everything was out is the best thing you could have done.

we have allot of yanks on here so your in good company, 

 

also welcome and build thread or ban

[bakwoods]

Thanks mate, unfortunately there's no yanks here so I'd be relying on someone over in AUS to yank the Rb25 chassis, engine and trans harnesses.

Since that's not a feasible option, any possibility of wiring in the trans to the 20 harness?

[KiwiRS4T]

The RB20DET ECU should be able to run the RB25DET engine. However if the RB25 has VCT then you will need a separate switching system for that.

But if the RB25 auto ecu is in the engine ecu then your RB20ECU may not do the job. You will need to google for some wiring diagrams to see if the RB20ECU has the auto ecu built in. Sorry don't have time at the minute to research it myself but would be a good idea for you to sort this before you spend ny more money (hopefully someone will pop up who knows the answer).

In the meantime how about a couple of pics of your car?!

[bakwoods]

Thanks @KiwiRS4T we figured out that the RB20 ECU can and will run the RB25 motor, however it won't run the RB25 transmission which is where my headache is. 

I've been scouring the internet for a while before pulling the trigger on this build. Ideally identifying and sorting out the wiring issues first and moving to mechanical second. 

There's some pictures of the Skyline. The badge on the back says GTR (previous owner) and the badges on the side say GT lol. So there's no consistency whatsoever, though I'd like to make this car my unicorn and do the unthinkable by dropping the RB25DET motor and trans into the R32 chassis and unleashing a monster onto the world. 

[PranK]

GT badges are on all R31's through R34 (i think) as well as S13 through S15 (again, i think) the colours of the GT badge represent whether the car is turbo or not. 

Looks nice! I thought US could only import GTR's?

Welcome to the site. We're definitely not Aus only.

[niZmO_Man]

IIRC, blue GT badge on guard = N/A
Red badge = turbo

[PranK]

5 minutes ago, niZmO_Man said:

IIRC, blue GT badge on guard = N/A
Red badge = turbo

Yep thats my understanding also.

[bakwoods]

The badges I have are all discolored actually so there's no telling what it was, I'm assuming red as the car is boosted. Though as you might have seen in my other thread, I plan on doing a neo swap, the challenge is the wiring. I won't go into too many details lol. 

Trying to score C34 or R34 GTT chassis harness and cluster so that I can run in the car. Wouldn't be fun otherwise.