DadsYellowGoat

iTrader: (1)

I have an 04 gto with an STS and a forged bottom end. Recently when running down the track the trans did not like the power and the bumped the rev limiter around 7k. When I made the turn onto the return road the oil warning came up. At the time I did not have a gauge but the engine was quiet I drove the car home and since installed a mechanical gauge and a RPM trans. The oil pressure problem is real when the engine is cold w/20-50 wt oil it has 40 idle when it gets hot it drops to ~15 or less. Two interesting observations. Switching from 10-30 to 20-50 did not change anything. Under WOT full boost acceleration the oil pressure drops starting around 25psi against the converter and letting off when I saw 10psi after it shifted into third gear. I am thinking that if this was a bearing problem it would have launched during one of 6,500 rpm passes (3) I made with it since this first showed up. Although I do not know what the oil pressure was previous to the over-rev the waring light never came on before. Is there anything that makes any sense to check before pulling the engine.

Thanks - Lanse

PREDATOR-Z

Well 40 at idle is normal, but 10>15, something is seriously wrong.
where are you tapping the oil supply for the turbo?

DadsYellowGoat

iTrader: (1)

From main oil galley just above the oil filter

PREDATOR-Z

Is that a standard oil pump or did you ever remove it?

DadsYellowGoat

iTrader: (1)

it was modified when the bottom end was done and it worked fine up to a couple weeks ago

PREDATOR-Z

Before tearing the motor, that is where I would look, oil pump or pump O-ring