Can anybody help me with this question? I have an L-28 motor in my 240Z with an oil cooler in the front of the car and as far as I can tell a stock pan. My problem is that the oil pressure is aonly about 10 - 15 lbs. at idle and when she's running at about 3-4000 rpm the pressure is about 40-45lbs. The guage itself seems very sluggish in response to revving ( it doesn't snap to life). I have replaced the the sending unit and have also installed a mechanical pump and have had the same results. The oil pump is new but is a non turbo type. Should I purchase the uprated pressure springs or go to a turbo type pump. IS all of this concern due to the oil cooler?