the factory guage isnt in psi...so on stock boost it only goes to about half way in the positive side...even doing the boost trick it doesnt go much higher on the stock guage...u need an aftermarket guage to accuratly know what its doing....by the way in doing the boost trick ur cutting the black wire and putting it to the chassis yes? because in that thread there was a bit of confusion about which wire it was...ive done this to my car and it is the BLACK waire that needs to be grounded...