Ball bearing turbos oil restriction?

[gezed]

Just got some bb gt2860r-7's wondering if its necessary to put in oil restrictions since i've heard that bb turbos need less oil compared to stock journal bearings plus high oil pressure can cause the seals to go prematurely.

I've found some restrictor banjo bolts have anyone used them before?

Any input would be much appreciated

Update: found some good reading material on this topic

http://www.turbobygarrett.com/turbobygarrett/faq

[MattiasJacobs]

I'm using the same turbo's with all stock lines. No problems.

[gezed]

^ how long have you been running those turbos?

[MattiasJacobs]

Not long enough to blow out any seals. I'm actually questioning this myself now. I've just skimmed through this discussion.

http://www.sr20-forum.com/turbo/30095-oil-restrictor-gt28rs.html

[Sharkus29]

i have the same ones, they have a built in oil restrictor.

[PurpleStreak]

this is definitely necessary, ball bearings do not benefit from the regular engine oil pressures..you will lose out on response and have more seal leakage without a restrictor..as for the type of restrictor, you may see higher pressure drop thru the banjo bolt than thru the restrictor but should be marginal..so you could use either a banjo bolt or inline restrictor.

I'm trying to use the banjo bolts but I'm having trouble with the sizes


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[gezed]

how much of an restriction should i go though? the stock banjo bolt is roughly 5.6mm diameter and the restrictors i find go down to as low as .8mm which is very small compared to stock so im really wondering if thats enough feed of oil for these turbos. Apparently they are an absolute must of you have a high flow oil pump such as Nitto or Tomei

[MattiasJacobs]

I think that its supposed to be .8 mm. Apparently you can buy the banjo bolt alone with the restrictor built in on ebay. I think ill be doing that just to be safe because it seems like the cheapest easiest way.

[Terrh]

All the garrett BB turbos that i've bought have had a restrictor built in.

[PurpleStreak]

All the garrett BB turbos that i've bought have had a restrictor built in.

I've heard this too, but I have trouble finding a document that actually shows a restrictor built into the turbos. Even the Garrett website FAQ recomends a restrictor upstream of the oil inlet.

The minimum restrictor size should be 1.0 mm for a stock setup, and 0.8mm for a higher spec oil pump.

[MattiasJacobs]

I've read about the built in oil restrictor too but I'm not sure why they would have there faq about using a restrictor if it has one built in and if it did actually have a built in restrictor why wouldn't they make it the right size? Lol beats me!

[Sharkus29]

If you bought the GTR replacement GT2860R -7 they have the built in restrictor. I have them. You can see the restrictor

[malibusst]

thats not a restrictor in the turbo, thats jsut the small opening port,

stock GTR oil feed lines have a restrictor built in. its the banjo bolt thats in the block, look closely, youll see it only has a .050 hole in it. which is okay for 2 BB turbos.

[MattiasJacobs]

0.050 inches? That equals 1.27mm. I guess the best way to ask is should you add the restrictor just for peace of mind? For me, my build is coming to an end without any cut corners and having something be persay, just "okay" isn't an option for me lol.

[PurpleStreak]

thats not a restrictor in the turbo, thats jsut the small opening port,

stock GTR oil feed lines have a restrictor built in. its the banjo bolt thats in the block, look closely, youll see it only has a .050 hole in it. which is okay for 2 BB turbos.

The oil feed restrictor for the block is the restrictor spec'd by Nissan for the stock journal bearing turbos. There's no telling that these are adequate for ball bearing turbos without design calcs or first hand experience. You will get a larger pressure drop thru a restrictor at the block since it sees 2x the flow, but that still may not be enough.

Here is some first hand experience:

http://www.gtr.co.uk/forum/119365-gt...estrictor.html

And I've haven't read about any horror stories for using additional restrictors on BB turbos. The amount of lubrication required for these is much smaller than a journal/sleeve bearing..