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Turbo Oil Feed And Return


81sigma

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Im thinking of turbing my new peice. Just one question if anyone can help, i know i may have to drill a hole in my oil sump, put a nut in there and weld around it for the oil feed. But is there any other way of hooking up the oil feed and return? or making its own oil box or sumfn :doubt:

chur

dave

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it's not hard to put a return in the sump, just make sure it goes in above the oil level, so close to the top. Then make sure that the pipe doesn't get in the way of the sump bolts.. i did that once..

carb jets make good oil restrictors btw

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It's only BB turbos that need restrictors. Fitting one might kill the turbo.

As said, take the oil feed from the pressure senders hole via a tee.

If you mount the turbo on top of the cam cover, you can drain it back into the cam cover instead of the sump. It's far easier.

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Forced is 100% right!!

Restrictors are a hack to make up for poor drainage. I can link you a bunch of material on this, but just trust in jesus name and believe that you do not want a restrictor, and you do want the best drain possible.

The trouble is that the restrictor restricts the most when your turbo NEEDS the most oil. Do not use one if you value your turbo. Also, BB units often/usually/sometimes come with a restrictor built in. They only need to be wet, journal turbos, like your mains and big ends etc, NEED pressure, not just flow.

Fred.

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Be VERY wary of using fittings on the head for oil supply to the turbo, most heads have a restrictor (again...) between block and head to ensure that A the mains and big ends are always well fed, and B the head doesn't flood and overflow. If you take your feed from the head and it runs low pressure because of a plug in the block to restrict head pressure/flow, you run exactly the same risks. It is possible that some heads have a different way of restricting oil flow and that high pressure is available in the head, but I'm guessing not many/if any because the headgasket would have to hold that pressure too.

You need a fitting post oil pump and preferably post filter pre-head from the main gallery. You can get this by drilling/tapping or by Ting the pressure sending unit. My mazda block has a spare 1/8 npt fitting on the block which came in very handy for an oil feed :-)

Watch this :

No restrictor, nice tight new turbo, note, oil pressure stays above 5psi for 30 seconds after the key is switched off!!! Journal bearings make an excellent restrictor indeed.

The drains really do have to be good though, as a LOT of oil flows through them at higher revs. If the oil backs up to the seals, it will "blow" by them and create smoke. If the drain is good, that will not happen. Worn bearings could create an excess flow issue I guess, but the fix for that would have to be new turbo/rebuilt turbo, not a restrictor...

Fred.

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11. 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 14 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.

12. 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.

13. 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).

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

torque speed.

The journal bearing system in a turbo functions very similarly to the rod or crank bearings in an engine. These bearings require enough oil pressure to keep the components separated by a hydrodynamic film. If the oil pressure is too low, the metal components will come in contact causing premature wear and ultimately failure. If the oil pressure is too high, leakage may occur from the turbocharger seals. With that as background, an oil restrictor is generally not needed for a journal-bearing turbocharger except for those applications with oil-pressure-induced seal leakage. Remember to address all other potential causes of leakage first (e.g., inadequate/improper oil drain out of the turbocharger, excessive crankcase pressure, turbocharger past its useful service life, etc.) and use a restrictor as a last resort.

etc.

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