View Single Post
Old Jan 24, 2015 | 09:18 PM
  #17  
Karlos G's Avatar
Karlos G
Balls Deep!
iTrader: (4)
 
Joined: Jan 2007
Posts: 9,185
Likes: 25
From: Suffolk
Default

Originally Posted by zetaboostboy522bhp
i dont think so mate as ive read up for months about wet sump ystems and dry sump systems to find out which is best for my engine .
this might help you as its off garretts webpage
The intake and exhaust plumbing often receives the focus leaving the oil and water plumbing neglected.

Garrett ball bearing turbochargers require less oil than journal bearing turbos. Therefore an oil inlet restrictor is recommended if you have oil pressure over about 60 psig. The oil outlet should be plumbed to the oil pan above the oil level (for wet sump systems). Since the oil drain is gravity fed, it is important that the oil outlet points downward, and that the drain tube does not become horizontal or go "uphill" at any point.

Following a hot shutdown of a turbocharger, heat soak begins. This means that the heat in the head, exhaust manifold, and turbine housing finds it way to the turbo's center housing, raising its temperature. These extreme temperatures in the center housing can result in oil coking.

To minimize the effects of heat soak-back, water-cooled center housings were introduced. These use coolant from the engine to act as a heat sink after engine shutdown, preventing the oil from coking. The water lines utilize a thermal siphon effect to reduce the peak heat soak-back temperature after engine shut down. The layout of the pipes should minimize peaks and troughs with the (cool) water inlet on the low side. To help this along, it is advantageous to tilt the turbocharger about 25° about the axis of shaft rotation.

Many Garrett turbos are water-cooled for enhanced durability.

this clearly states where the return should be placed and the exact same problem i had on the dyno with my engine.

hope this helps

cheers paul
Ah I see the confusion, it's specifically talking about the BB range, these have very little oil flow and a plastic bearing cage... letting these heat soak or restricting the oil return could be disastrous.

You wouldn't however get any problems using an old T series Garrett below oil level much like they are happy to run without water cooling.

The OP says he's using a T25 but from a Focus RS, I think he most likely means a GT25 as that's what was fitted to the FRS, in which case I agree it must be water cooled and the return should be above oil level.

Last edited by Karlos G; Jan 24, 2015 at 09:20 PM.
Reply