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Oil Supply & Drainage

Journal Bearing Turbo

"Journal-bearings function similarly to rod or crank bearings in an engine - oil pressure is required to keep components separated. An oil restrictor is generally not needed except for oil-pressure-induced leakage. The recommended oil feed for journal bearing turbochargers is -4AN or hose/tubing with an ID of approximately 0.25. Be sure to use an oil filter that meets or exceeds the OEM specifications. "

Ball Bearing Turbo

"An oil restrictor is recommended for optimal performance with ball bearing turbochargers. Oil pressure of 40 - 45 psi at maximum engine speed is recommended to prevent damage to the turbocharger's internals. In order to achieve this pressure, a restrictor with a 0.040' orifice will normally suffice, but you should always verify the oil pressure entering the turbo after the restrictor in insure that the components are functioning properly. Recommended oil feed is -3AN or -4AN line or hose/tubing with a similar ID. As always, use an oil filter that meets or exceeds the OEM specifications. "


Oil Drain

In general, the larger the oil drain, the better. However, a -10AN is typically sufficient for proper oil drainage, but try not to have an inner diameter smaller than the drain hole in the housing as this will likely cause the oil to back up in the center housing. Speaking of oil backing up in the center housing, a gravity feed needs to be just that! The oil outlet should follow the direction of gravity +/-35° when installed in the vehicle on level ground. If a gravity feed is not possible, a scavenge pump should be used to insure that oil flows freely away from the center housing.

  • Undulations in the line or extended lengths parallel to the ground
  • Draining into oil pan below oil level
  • Dead heading into a component behind the oil pan
  • Area behind the oil pan (windage tray window) where oil sling occurs from crankshaft

When installing your turbocharger, insure that the turbocharger axis of rotation is parallel to the level ground within +/- 15°. This means that the oil inlet/outlet should be within 15° of being perpendicular to level ground.

Water Lines

Water cooling is a key design feature for improved durability and we recommend that if your turbo has an allowance for watercooling, hook up the water lines. Water cooling eliminates the destructive occurrence of oil coking by utilizing the Thermal Siphon Effect to reduce the Peak Heat Soak Back Temperature on the turbine side piston after shut-down. In order to get the greatest benefit from your watercooling system, avoid undulations in the water lines to maximize the Thermal Siphon Effect.

Negative degrees: water outlet of center housing is lower than water inlet Positive degrees: water outlet of center housing is higher than water inlet

For best results, set the orientation of the center housing to 20°.
Significant damage to the turbo can occur from improper water line setups.

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