Hey guys. I drive a 1997 lexus sc300. I would like to boost it and I'm trying to figure out how much boost I can run on a stock fuel system and a stock ECU. And how much power would that equate to? Anything helps. Thanks

 

For a 92-97 GE block what you should be looking into is an OEM 2JZ-GTE metal multi-layer steel head gasket swap to lower the compression ratio from 10.0:1 to about 9.2:1. Then it's better to switch from a factory 2JZ-GE ECU to a stock 2JZ-GTE Non-VVT-i ECU, most commonly and cheaply sourced from a JDM Aristo GTE model. There is enough solid air-fuel mapping in those ECUs to support up to around 500whp or so before you'd need to switch over to an aftermarket standalone ECU. There is a good guide by Ali SC3 detailing how to wire up your SC300's 2JZ-GE for use with a factory 2JZ-GTE ECU.

The oil pan turbo drain is best done with the pan off and with the head gasket swap being part of this it makes sense to temporarily pull the engine to do all of this, freshen things up, install a 1996+/VVT-i 2JZ-GE oil pump just to have the location for a factory crank sensor.

In addition you would want to upgrade your fuel injectors. The cheapest I think, unless things have changed, is an upgrade from the factory 330cc GE injectors to 440cc GTE injectors (good for around 400whp or a bit more before you'd begin to go beyond 80-85% max duty cycle... which is not recommended with any type of injector). Additionally you'll need a Denso Supra TT fuel pump, a dedicated 10ga 30A fused direct battery power wire running to your stock fuel ECU and a 30/40A relay using your stock SC300 2JZ-GE Fuel ECU as the trigger wire to make that relay turn on and off. All of that will take care of the fueling side of things.

Also you'd need to consider swapping out your GE-spec 4-speed automatic transmission for a stronger 2JZ-GTE or 1JZ-GTE spec 4-speed automatic transmission so as to better handle the power. If you want to swap to a manual then I'd recommend going the R154 or converted AR-5 route.

And the front brakes should be upgraded to 1995-2000 LS400 front calipers and rotors at minimum.

Beyond all of this, being in CA you're not going to have an easy time running any 2JZ-GE NA-T setup. The alternative is converting a 2JZ-GTE Non-VVT-i engine to stock USDM spec with factory emission control parts. Doable but very tedious and time consuming to get right.