'90 GGSX / '92 VR4 Compatability Questions

[donkeylips]

Hey everybody my brother owns 924/1000 and its a little rusty so we're picking up a clean '90 ggx and swapping everything over that we need from his vr4. Then I will take the parts from the ggsx(and spare dsm parts) and put them on the gvr4 to make the ultimate year round bastard galant. Both cars will have either a 14b or 16g.

GGSX: ----> no problem
-Engine w/turbo, '92 wiring harness, non-eprom dsm ecu taken from gvr4
-1g dsm trans, t-case, 4-bolt rear, 5-lug swap

GVR4 -----> this is where I have the questions
-Engine w/turbo, turbo dsm ecu, modified '90 ggsx wiring harness??
-1g dsm trans, t-case, stock gvr4 rear end

I know which components to use such as clutches/flywheels/injectors/fuel pump/etc. If this were a '91-94 NT dsm I would have no problem making the necessary modifications to go turbo, but here's what I'm looking for.

I tried searching around and couldn't find out if the '90 ggsx has differences similar to a '90 dsm (I don't have the car yet, its in PA and I'm in Rochester, NY). Is the wiring harness similar to a '91-94 NT dsm or a '90 NT dsm? Are the CAS, fuel rail, etc like a '90 or '91-94 dsm? I don't really want to shell out the money for a gvr4 wiring harness, and I couldn't find what kind of modification is required to make a dsm wiring harness work in a Galant.

The 3 wiring harnesses I have available:
-'90 ggsx
-'90 turbo dsm
-'91 NT dsm

And I can use my '90 turbo dsm ecu or get a '91-94 turbo dsm ecu. What's my easiest combination here? Or should I just save up and get a vr4 wiring harness and use all '91-'94 components?

 

[1990ggsxnj]

I just started looking into the conversion for my GGSX as well and was wondering the same thing.

 

[IncorpoRatedX]

click

 

[donkeylips]

I did some CAPS research and while I never got around to comparing the parts from the '90 gsx to the '90 dsm, I compared the vr4 and gsx. Looks like the parts on the gsx are mostly the same as the '90 nonturbo dsm. Which is a bit of an oddball... its easiest to get '91-94 components and either a gvr4 wiring harness or a '91-'94 harness that you can modify to make work. Its basically the same, but the wire lengths are probably different , so maybe do a wire tuck while you're at it?
I recommend running a dsm drivetrain, but you'll need to swap the shifter and cables.

 

[1990ggsxnj]

Quoting Alpha Male:
click



? was more along the line of electrical additions. I know that everything on my TB looked exactly like a 91 which threw my "similar to 1990 dsm wiring" out of the door. I can't find my damn service manual for the routing/color coding/pinouts to do the conversion like I had on my 91 Eclipse GS and am unsure if any of the ECU pins need to be swapped.

 

[Muskrat]

That's prettyb easy to confirm. Just ohm out the wires and see what goes where. It's either right, or it isn't.

 

[1990ggsxnj]

Indeed, that's always a good fallback.