Oil Cooler on Turbo Feed Line?

[Sugarphreak]

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[mr2mike]

My inital thoughts would be don't unless you can confirm there's no pressure drop in oil feeding to your turbo. But I think there would be.

Starving the turbo of oil is 100x worse than just running hotter oil into it.

Plumb in coolant lines to the turbo if you're concerned with heat/longevity.

[ercchry]

Originally posted by mr2mike
My inital thoughts would be don't unless you can confirm there's no pressure drop in oil feeding to your turbo. But I think there would be.

but dont most turbos need a reducer anyways cause pressure would be too great otherwise?

[mr2mike]

Some do, some don't...
From Garrett:

A. Oil requirements depend on the turbo's bearing system type. Garrett has two types of bearing systems; traditional journal bearing; and ball bearing. 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.

Garrett distributors can tell you the recommended range of acceptable oil pressures for your particular turbo. Restrictor size will always depend on how much oil pressure your engine is generating-there is no single restrictor size suited for all engines.

Ball-bearing turbochargers can benefit from the addition of an oil restrictor, as most engines deliver more pressure than a ball bearing turbo requires.
The benefit is seen in improved boost response due to less windage of oil in the bearing. In addition, lower oil flow further reduces the risk of oil leakage compared to journal-bearing turbochargers. Oil pressure entering a ball-bearing turbocharger needs to be between 40 psi and 45 psi at the maximum engine operating speed. For many common passenger vehicle engines, this generally translates into a restrictor with a minimum of 0.040" diameter orifice upstream of the oil inlet on the turbocharger center section. Again, it is imperative that the restrictor be sized according to the oil pressure characteristics of the engine to which the turbo is attached. Always verify that the appropriate oil pressure is reaching the turbo. The use of an oil restrictor can (but not always) help ensure that you have the proper oil flow/pressure entering the turbocharger, as well as extract the maximum performance.

[Cooked Rice]

If your oil temps were that high, I'd be more worried about cooling the oil
supplied to your engine vs the turbo.

[DeleriousZ]

Even without a restrictor the bore size of the internal feel ports to journal bearings is like 100thou or so at most, feed to thrust bearing can be up to .125/.25 (diesel turbo's)depending on turbo size. a -4 size line is more than enough size wise.

as for the cooler, you probably wouldn't want one inline with the feed line, you want temps to get hot (to operating) as quick as possible going to the turbo, cold oil isn't good for journal bearings.

As said above, if you're worried about oil temps, it's best to keep the entire system properly regulated. You'll want a thermostatic switch with bypass somewhere in the system to keep the oil away from the cooler until it reaches operating temp and/or so it's not overcooled.

[mr2mike]

If you're worried about coking the feed line. Use a turbo timer.

[Sugarphreak]

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