What psi do i set the pressure switch on a 2d?

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I have it turning on right now at 10psi. Is there a formula for when the wi should be activated? EGT temp?

[JohnA]

EGTs are not a good indicator for W.I.
In fact they are not affected as much as one might expect.

There are no hard-and-fast rules on the activating pressure, because it depends how far you've exceeded the manufacturer's safety margins.

A good start is just before the max point that the manufacturer expected the car to operate.
So if the stock setup used to go up to 11psi, and now it's boosting up to 20psi then activating the WI at 10psi is a good starting point. Better intercooling can help shift the point upwards, just like low ambient temperatures (below 10C for example)

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Ok. I have a supra and the stock boost level was 14.7psi. We no longer have a stock engine but have fully built the supra block with je pistons, headwork etc.... and strapped on a DBB76mm turbo on it. We are fully built from the driveline all the way to the intake. What is the goal in tuning for WI or metahnol? Do i keep it from injecting until i see the egt's climb wich will indicate the ecu pulling timing from knock? Supra ecu's don't monitor knock unfortunatly so we can't see what is going on other than by watching the egt's climb.