So I've read several things that talk about the inability to control boost with too much breathing on the engine. But what mods can I safely do without upgrades to the ECU? I'm moving from Japan to Italy and hopefully will be find someone to tune it there. But while in Japan I wanted to pick up a nice intake and exhaust. Since JDM version has no pre cat, is the downpipe upgrade needed? Will the catback exhaust improve performance but still maintain some resistance for the turbos? Or will it need some kind of resister plates? What other mods can be performed without ECU upgrade?

 

What year is the car, and what modifications does it currently have?

 

Its a 95 Efini Type R Bathurst fully stock

 

 

If the car is all the way stock, leave it that way. Once you go poking around doing mods that add nothing to performance, that's when you start getting problems. Don't mod the car just for the sake of doing it. With that said, The stock exhaust is fine but a catback won't hurt just to give it a little more volume. There are people that run 100% stock cars with a stand alone. You're able to get better everything ditching the stock ecu, not that there's anything wrong with it. It's just the compromises made from the factory to the tune can all be removed and improved upon with a stand alone. Also, the stock air box or it's aftermarket equivalent in design is the best our cars will ever see. Switching to those pod type filters that sit entirely in the engine bay and get nothing but scorching hot air is a terrible idea. Your ait will go into infinity and the stock ecu will loose it's mind trying to combat it. If you really want to mod the car, look into the universally accepted "reliability mods". Do those and leave it be. If it were me with an all stock car, I wouldn't mod it all. Stock exhaust and everything. Stock is the best way

 

*No, from what I understand you shouldn't need an aftermarket downpipe.
*I agree with what cr-rex said about opening the intake side to receive ambient air from outside of the engine bay and, hopefully, to reduce air it takes from the intercooler duct. That is possible and simple to do with the stock intake box and it's invisible. Search the 3rd Gen. Section for "Cheap Bastard" mod. There's also the AutoExe intake.
*As long as you hold the car to stock boost levels (10 psi) the stock ECU should be fine. Years ago we used to use something called the "3 mod rule" which you can also search the FAQ sticky for. It's pretty self-explanatory and, IMO, still valid. IIRC one of the mods was usually a downpipe because our cars came with that pre-cat which you won't have to worry about.
*I agree with cr-rex on performance mods, but still think reliability mods, like an all metal radiator and metal AST are worthwhile.

 

when were ecu's mandated by the federal government?

 

Indirectly when obd was required probably.... where did that question come from?

 

someone tried to sell me an ECU for my 1983 rx-7 carburator'd car............I said in 1983 , no one knew that computers existed.

 

Good thing you're not a fool

 

so when were ECU's required by the EPA?.....and yes, I did a search.

 

I already said.... they weren't. Through technology advancements and efi, an ecu made itself necessary. Then obd became a thing and became a requirement, thus indirectly making an ecu a requirement because you can't have obd without one.

 

And the answer to today's Double Jeopardy Question is>>>1996

Motivated by a desire for a statewide emissions testing program, the CARB issues the OBD-II specification and mandates that it be adopted for all cars sold in California starting in model year 1996 (see CCR Title 13 Section 1968.1 and 40 CFR Part 86 Section 86.094). The DTCs and connector suggested by the SAE are incorporated into this specification.

I was calling it the wrong thing.

 

Yes, you were. And we knew that computers existed in 1983....Sonny-boy. There was one on a desk next to my IBM Selectric.