When doing any boost install to the Lexus IS300 or GS300, one must take absolute consideration of the limits of the engine, fuel system, engine management and operating environment, before you find yourself with a blown-up engine.
There is much discussion on how much power the stock fuel system, engine management system, etc., the engine can handle. It is our "base" experience that on the factory small fuel injectors you can run about 285 RWHP safely. Safely would be defined as injector duty cycle limit not exceeding 85% with an air fuel ratio under boost of 11.5 to 12.0 to 1 on good quality premium unleaded fuel. I know people have made 375rwhp on factory injectors, but this is our opinion of "safe", not everyone's.
Not every customer requires the complete Stage 1.5 Accessory Kit, and frankly, some just want to swap their IS300 from the returnless factory style fuel system to the "required" Return Fuel System, which is a must for any boosted application in the IS300. Without this, you cannot successfully install a proper fuel pressure regulator.
I said all that, to say this. We have this Fuel System Set-up Package which converts your factory fuel system to a return style fuel system. All parts are in this kit. Figure an afternoon to do the install for an experienced mechanic.
This kit contains the following:
Return Fuel Line Package:
FueLab 1:1 Rising Rate Fuel Pressure Regulator -6 AN
1000 psi rated fuel line kit
All AN fittings
Fuel pressure gauge (mounts to FPR)
Other fuel pumps are available at extra cost for those needing more fuel flow!
If you are building a dual or triple feed fuel setup for your GS/IS, please contact us as we have a separate kit for you to fit your needs