Oil Restrictor For Bb Turbos?

[gabbo32gtr]

hey all,

just bought -5's for my gtr and am looking into braided oil and coolant lines. i read somewhere that on ball bearing turbos on gtrs the oil supply line needs a restrictor in it? any truth behind this? does it have something to do with the size of the supply line?

all help greatly appreciated

[R31Nismoid]

Ball bearing turbos have restrictors built into the cartridge themselves - most of the time.

Additionally sometimes you also require inline restrictors - this is regardless of the size of the line (to answer one part of your Q).

Unsure of whether -5's need them, I've not installed them... Someone else will know

Side note - I can't remember my GT-SS kit coming with restrictors, but it has been 3 years now.

[The Dan]

Garrett GT BB turbo's all have the restrictor built in. -5's included 0.8mm

The only time you would need to restrict more is if you had an external oil pump that flowed like 40L/min at 2000rpm.

[gabbo32gtr]

legendary. thanks guys.

[paulR32gtr]

Reason why you need the restrictor is because bush bearing turbos (like stock 32r's) like more oil - BB turbos dont need anywhere near as much and it causes problems if there is too much

[C4NC3R]

On a similar note, not to Hijack the thread but the OP seems to have his answer, if I was to go from a HKS GTRS ball bearing that I'm assuming will have a restrictor, to a different non-BB turbo, would I still be able to use all the GTRS braided lines from the kit and just change the banjo bolts, or is the restrictor in the line also?

[The Dan]

On a similar note, not to Hijack the thread but the OP seems to have his answer, if I was to go from a HKS GTRS ball bearing that I'm assuming will have a restrictor, to a different non-BB turbo, would I still be able to use all the GTRS braided lines from the kit and just change the banjo bolts, or is the restrictor in the line also?

The restrictor is IN the turbo.

If you are going to change to a journal bearing turbo, you will need more oil flow. Usually you can add a restrictor into the top of the turbo but you need to check oil flow through the drain when the engine is running. Check with your turbo manufacturer for oil flow specs required. They will know

[R31Nismoid]

Yeah i highly doubt the braided line you have now will let you flow what a journal bearing item will need

[tridentt150v]

Also be careful with your fittings. Sometimes the bolt that is used to attach the feed side banjo to the block has a restrictor in it, you can see this easily when you undo it and visually inspect it.

[D_Stirls]

From the Garrett Website;

http://www.turbobygarrett.com/turbobygarre...r/faqs.html#t16

Does my turbo require an oil restrictor?

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.

[tridentt150v]

0.040"=1.016mm

[C4NC3R]

Yeah cheers guys, I knew there was one in the GT-RS itself, and there's also one on the block, so I've taken that out. What makes you think they'd put restrictors in aswell as use smaller lines?

[femno]

Generally, if youre bolting on a BB turbo to your standard engine :read standard oil pump and pressure / volume: you dont need any restrictor.

If you have a rebuilt engine running higher than standard oil pressure, then you need to work out some sort of restrictor.

[C4NC3R]

Yeah, I'm just trying to work out if I'll be able to reuse the braided lines I currently have from my GT-RS when going back to a non-bb turbo. I'ma try to take out the restrictors and chance it, if the turbo dies that'll give me an excuse to take it apart and play =P

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