LS Dry Sump low oil pressure

Hey All,

I have an L98 with a recently installed dry sump system. Details below.

The problem

- On the Dyno after putting everything back together the engine ran with oil pressure hitting 70PSI early in the rev range, holding until approx 6K RPM and then tailing off to around 60PSI for the last 1000 RPM. multiple runs it did the same thing.

- Out on the track , initially the engine would run high pressure at idle when cold and then drop over time with oil temp. took the car for a shake down the other day. The engine really only reved to around 5k a couple of times, pressure was reasonable through out this period. It would increase with revs and at idle would drop to around 20 psi. Last outing engine oil temp hit 110 deg and the oil pressure started to drop quite low (20 PSI) whislt at 2-3K RPM. I let off an oil pressure dropped to 5-10PSI at idle. Limped it back into the pits and now it wont hold pressure when cold.

- Now the engine will fire up and oil pressure is roughly 60PSI. This will slowly drop to 15 psi over the course of a few minutes. Just warming up at idle. The oil temp is still quite low at this point, around 45 deg. Any rev increase will drop the oil pressure, not keen to rev to high as i dont want load with low pressure. sitting at 20PSI at idle a throttle blip will drop pressure down to 15PSI, if i leave it running any longer it will continue to drop in pressure.

The set up

Dailey SP series oil pump two scanvenge off billet sump pan, and 1 pressure stage.

Suction is -16 100 series hose with internal spring, run to Peterson 3 Gallon tank moounted in the rear of the car.

Pump discharge is -12 100 series hose through Peterson primer and filter housing. then on through oil cooler and into the oil inlet on the bottom of the block. The feed is on the rear of the block on the stock filter location. through the barbell and into the oil galleries. The stock pump is removed and inlet to block has a plug in it.

Pump Scavenge is also -16 back to the tank.

Oil is 10W40, running engine at 2000RPM will maintain a level in the tank just bellow the mesh at the mid point of the tank.

Bearing clearances are a little on the looser side of the tolerence, cant remember what they are at the moment.

If you have any advice as to where to start looking that would be much appreciated.

Cheers