JDM GT to GT-B Engine/ ECU conversion

[Robbks]

Ok, now i'm most of the way through this I thought that i'd post up my findings on this headfcuk of a process.

My car is originally a JDM Legacy GT Automatic (EJ20H, 180KW)
it has had a new engine from a JDM GT-B Manual put in it (EJ20R, 206KW)
It always ran very lean until i changed injectors and added a haltech interceptor to adjust fuel mixtures. however it has always been a little sluggish to drive due to the differences in tune, compression ratio, etc

So i decidied to tackle the feat of swapping in the proper factory ECU to suit the engine, which is not a simple plug and play affair. it requires a complete re-pin of the factory loom.

I can see why the pro's charge a reasonable sum of money for doing this as it's bl00dy fiddly and has serious consequences if it's wrong.

I'm also adding some complexity by making an adaptor loom as opposed to doing a straight out re-pin,
for the simple fact that if it won't run with the new ECU plugged in, reverting back to stock and getting to work tomorrow will not be a hassle.

The V3 STi re-pin is a little different as there is no need for all the TT solenoid box wiring, and the fuel pump and ignition pinouts are slightly different

So here's the info that I armed myself with

Pin Allocations for GT


Pin Allocations for GTB


And the match ups


here's the hacked GT ECU to get the connectors and the GTB connectors that together will make the patch loom

[httrdd]

This a a how-to not a question thread right?

[Robbks]

Yes, sorry.

I'll update the thread with the other parts that need to be wired in and changed as i progress

mods if it needs moving, feel frere.

[Robbks]

Right,
206KW EJ20R Engine/ ECU and sensors are all in and running
FINALLY

there were some discrepancies with the wiring that i have posted above and as such i need to update it.

the major issues that i encountered was the fact that the GT and GTB have slightly different looms in that the GTB links a lot of it's senor earth's into a junction before they are passed via a single wire to the ECU.
The GT runs individual earths to the ECU for each sensor, and as such these extra earths did not translate across in my research, so they were left disconnected.
this caused issues with the AFM and thermo-fans
But i still need to conduct some final testing on the TT's changeover system, but it all appears to operate correctly...