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wmunchovie wmunchovie is offline
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Join Date: Nov 2007
Posts: 58
If they would have understood the dynamics of the turbo oiling system then maybe the vent less aftermarket turbo sump tank would have never been born…

Turbo cars are going to eat some oil. The amount of oil flowing over the turbo bearing is substantial especially at high engine RPM’s - gasses are created as part of the bearing lubrication/cooling process. There is also a measure of cross flow of gasses from the hot and cold side of the turbo which escape past worn bearing seals into hot and cold side as well as the oil dump outlet on the bottom of the turbo which is connected to the sump tank.

Enter the turbo vent pipe on the factory tank. During periods of sustained peak boost at high engine RPM’s, one could easily envision oil in the sump being backed up into the vent tube, into the oil breather hose with some quantity oil/oil vapors being sucked into the air box (although the factory air box is big, the vacuum created by the turbo on the filter side is tremendous and will quickly overcome the filter’s rated flow capacity thus causing other circuits to normalize that lack of adequate flow- the turbo vent/breather tube being one of them).

The case of the “missing motor oil” could easily be attributed to worn turbo bearing seals, a weak scavenge pump which is out of spec, the addition of a larger turbo with an increased flow rate across the bearing surface, an improperly sized sump tank. The possibilities are myriad.

Anyway, that’s my take

Is 13 lucky or unlucky ?
Old 12-14-2007, 06:34 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)