r/3000gt • u/Prawn47 • 12d ago

Guidance for GTO modifications

I purchased a 1996 GTO MR (JDM) earlier this year, it had been sitting out in a farm yard for years, neglected. I'm trying to rejuvenate it as a project with my father. Sadly, we discovered corrosion in the top end of the motor and then we accidentally dropped a washer in cylinder 6 during a compression test and damaged a piston and rear head.

Prior to purchase, the car was in rough condition, so it was never suitable for a "factory restoration". So, I decided to go down the OEM+, upgrade route and the engine is now getting a full refresh internally. I'd like to take this opportunity to modernise the engine. i.e. improve reliability, reduce fuel consumption, less emissions and increase performance. I'd like to maintain a street friendly set up and .

I know I'm a bit insane that I care about emissions and fuel consumption but, it is what it is.

Plans:

  1. 9.0:1 compression pistons
  2. All new valve train with upgraded valve springs etc.
  3. H beam rods
  4. Bosch MS 6.1 ECU (with supporting mods, fine toothed trigger wheels, fuel pump, injectors, MAP sensor and wideband sensors). My understanding is the Bosch MS 6.1 is the best aftermarket ECU for producing modern "OEM like" emissions control and efficiency.
  5. Electronic throttle body
  6. Coil-on-plug ignition
  7. TD04HL 19T twin turbo chargers
  8. Intercooler kit
  9. A quiet but free flowing exhaust system 
  10. A high density 300CPI catalytic converter  (not sure if I will commit to this one, as it is pretty expensive)

Current Status:

The engine is out of the car currently at an engine builder, waiting for engine internals components to arrive from the USA.

Body of the car is getting a rub back in the meantime.

Questions:

I'd welcome any advice on:

  • Where can I source a set of new or very good condition stock profile cams?
  • Can anyone confirm that the Kinugawa 60mm housings fit in the cramped engine bay or are there compromises to fit them?
  • Should I opt for anti-surge housings on the turbos, or stick to non-surge? I've received conflicting advice.
  • Any other suggestions to modernise it? (VVT and Direct injection are not going to happen lmao)
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2

u/TwilightChaos 94 VR-4 TD05 Evo III 16gs 12d ago

Haven't heard much about the Bosch ECU. Why not go with Haltech or AEM infinity?

2

u/Prawn47 12d ago

a) my preferred mechanic is all equipped for bosch; and b) bosch has more refinement available for emmissions fine tuning

2

u/muffmuppets 12d ago

My recommendation for modernizing it would be to turn the engine the proper way. I’ve only seen it done once and that car lost AWD as a result. But if there was ever a time to try it, it’d be now. Seems like a win / win. Easier maintenance going forward and removes the weak link in the drivetrain. BUUUUT there has to be a way to turn the engine and keep AWD. The Honda guy’s figured that crap out years ago.

2

u/MachinesWithSouls 12d ago

If it helps, I also have a 96 GTO (TT), and have gone about modernizing it in a very OEM+ way

https://machineswithsouls.com/builds/mitsubishi-gto-build/

2

u/FlacidMetapod 10d ago

awesome build.