Originally Posted by EgRocker
with an Ls turbo is it really that important to have a hondata or a VAFC. they seam to control vtec. i would see why the fuel regulator is important but i don't understand why there should be two things controlling the fuel. hondata and fuel regulator.
Ugh. Make your own thread instead of reincarnating the dead.
Fuel regulators manage fuel pressure, which is something an ECU cannot do. Every car with fuel return has a fuel pressure regulator. The ECU (stock, Hondata, etc) is tuned based on a particular expected fuel pressure from the FPR.
If you tune your car with a FPR that yields 43 PSI, and replace that with an adjustable and crank it to 60 PSI, you will be overfueling. The ECU controls how long the fuel injectors are open, but the amount of fuel that comes out of the injectors during that time is entirely dependant on the fuel pressure in the rail. More pressure = more fuel per microsecond.