Hello Everyone,

I'm writing to get some insights, as I'm hoping to restore my car and running better than ever (hopefully). I'm rather inexperienced with tuning/engine stuff in general, so my assumptions might be incorrect, but here's what I'm thinking.

The car is a 1994 JDM STI. It's an OBD1 car, which from what I can understand highly limits how much the car can be tuned. My idea is to get a new ECU. As much as I'd love to get something fancy, like a Haltech, It's not really in my budget, hence I'm thinking of getting a ver 5/ver 6 ECU. At the end of the day, once all of the supporting mods are done I'd love to hit the 300KW mark, but that's far in the future. Right now, the goal would be to have the original ~180-200KW.

For the ECU upgrade part - from what I can tell I might need a new harness as well as additional sensors, would that be correct? Are there any other considerations I should have? I've no idea on the scope of a project like this as well. I'd love to take it to a shop and professionals install everything, as all of the electrical stuff does seem intimidating.

Or is there no point in going this route altogether and the gains will be marginal? My goal is to hit the 180-200KW, but do it properly with the car not blowing up.

Thanks!

 

you would be basically re-looming the engine bay and back to the ecu along with the clocks. you'll have to change the maf and IACV to what the v5/6 ecu expects as well. Not worth the aggravation for it when you can still get an ESL board for your v4 ecu and have it tuned to suit:
Enduring Solutions Website

Also your v4 is not OBD1 - it's not even OBD0 it's pre-OBD and uses the SSM (subaru select monitor) protocol.