RB30 forged bottom end, single cam head running rb25 oil pump and crank collar. Its going to be used maily for the street and occasionaly track days at Wakefield park. Im leaning towards 2 X 1.2mm restrictors but i have the option of going smaller 2 X 1.0mm or larger 2 X 1.5mm. What do you guys think is the best restrictor size? Sump is standard and turbo is GT35/.82R no idea of PSI or power yet as its in pieces.
You can always fit an oil return to the sump from the back of the head if you need to. I didnt have restrictors in my old single cam head and it used to flood the head, I ended up going twin cam but ran an oil return from the head as well as restrictors.
Im only guessing but 1.2mm front and rear. Really depends on the cam too.
Ive done the maths, engineering fluid mechanics is so useful. with 2 x 1.2mm restrictors and an RB25 oil pump which looks to flow 95-100 PSI @ 6000 RPM the flow rate to the head would be 0.181 Liters a second. A standard oil pump flows 60 PSI @ 6000 RPM the flow rate to the head with 2 x 2mm restrictors is 0.390 Liters a second (which is causing people problems) My question is what is the ideal flow rate for the single cam head?
*flow rates calculated at 80*C, Density of 852 kg/m3.
