The AUSubaru.com.au Forums

Is there some sort of fuel or spark cut for
4plug EA82's?

If so, at how much boost does it start
to take effect?

Just want to know why it started to knock at 8.5psi


Cheers,

Sam

fuel from a neighbouring country perhaps? not quite enough RON for 8.5 boost? Think it is near ten for 3 plugs unit to kick in the fuel cut

Fuel cut at about 8 psi,there is a pressure sensor mounted on the inlet manifold that does this.
You could try fitting a small mainjet such as keihin motorcycle CV carb jet into the hose to the sensor as the restriction will delay the pressure spike or fit a fishtank air control valve inline as well,this has the advantage of being adjustable and was an old trick for adjusting boost pressures.
By restricting this hose it will raise the fuel cut point as more boost pressure is required to actuate the fuel cut switch.

Fuel cut in 4 plug EA82T's is not sensed by a boost sensor like the earlier 3 plug ECU's.

Fuel cut is decided by air flow and the only way around it is by either a fuel cut defender (a series resistor in the AFM signal wire) or a piggy back ECU

Note that the fuel cut defender should be used with caution as it fools the ECU into thinking there is less air, which will cause it to run leaner