S2A inlet size

[paulojmoore]

Im running an S2A turbo with a 6mm oil inlet and 12mm return,  its a new turbo so seals should be ok but im getting specks of oil in the pressure system and an oiley/ smokey exhaust, dose anybody know what is the best size inlet restriction to use?  any help appreciated

[BeetleBug]

Try a 3mm inlet to see if it helps. I have a 2.5mm inlet on my turbo.

[paulojmoore]

thanks, do you put a 2.5mm restriction in the line or use a 2.5 pipe?

[BeetleBug]

thanks, do you put a 2.5mm restriction in the line or use a 2.5 pipe?

I'm using a steel braided teflon hose with a 2.5mm inner diameter.

[paulojmoore]

ill try that,  what kind of rpm do you make? im going to 7K and just a little worried about oil starvation at high rpm.  surpose i could just switch to a larger pipe at the track

[BeetleBug]

Well, your turbo is spinning with 100 000 to 150 000 rpms so not sure why you worry about your engine rpms. If it helps I do see 8000 rpms on my engine from time to time  

Also consider the up-sides by restricting the oil inlet and also restricting the pressure. Earlier spool is reported. This is directly from a Holset service manual:

Holset permits oil return pipes to decline at an overall angle of not less than 30 degrees below horizontal. All turbocharger applications require a pipe of internal diameter greater than 19 mm which has integrated connectors. To ensure oil returns into the engine under all operating conditions, the return connection into the engine sump must not be submerged and the outlet flange of the turbocharger must be 50 mm above the maximum oil level of the engine sump pan. Crankcase pressure should be limited ideally to 0.8 kPa (0.12 lbf/in2) but 1.4 kPa (0.20 lbf/in2) can be accepted by reference to Holset.

Oil pressure of 150 kPa (20 lbf/in2) must show at the oil inlet within 3 - 4 seconds of engine firing to prevent damage to turbocharger bearing system. A flexible supply pipe is recommended.

The minimum oil pressure when the engine is on load must be 210 kPa (30 lbf/in2). Maximum permissible operating pressure is 500 kPa (72 lbf/in2) although 600 kPa (88 lbf/in2) is permitted during cold start up. Under idling conditions pressure should not fall below 70 kPa (10 lbf/in2).

Recommended oil flows for the turbochargers are 2 litre/min at idle and 3 litre/min above maximumtorque speed.

ill try that,  what kind of rpm do you make? im going to 7K and just a little worried about oil starvation at high rpm.  surpose i could just switch to a larger pipe at the track

[paulojmoore]

was just thinking the higher the motor rpm the faster the turbo spins.
thanks, that info is useful, maybee the return is also too small!