Block oil feed banjo bolt restrictor

gtirx2

Member
I am sure it will proberly be fine with or with out but I am still curious.

I am fitting a gt2871 and have brought new fittings and banjo bolts, but on removing the stock oil feed block banjo bolt I notice that it has a restrictor fitted.

I assume this is a .065 restrictor for journal bearing turbos?

Question is why is this fitted, and am I best off keeping this original bolt or using a normal banjo bolt with the bb turbo?

Did Nissan fit this as a completely unrestricted line has to much pressure even for a journal bearing turbo?

If this is the case maybe I would be best off keeping it to lower the pressure a little as I am not running any other restrictors other than the stock one built into the bb turbo.

Then on the other hand although highly unlikely its another place to get blocked and its also before my feed filter,the hole is obviosly not as small as the .035 bb restictors so maybe not a cause for concern?

So go with the stock .065 banjo restrictor or not?
 

The Doc

Moderators
Staff member
The stock banjo bolt is fitted to restrict the flow of oil to the turbo not the pressure, if you take too much flow away from that oil gallery you will loose flow from the centre main crank bearing and conrod bearing 3. Use the restrictor bolt,
 

gtirx2

Member
I never even gave that a thought about the oil gallery, great info and just what I wanted to know, thanks Doc :)
 

fubar andy

Moderator & N/W Rep
Staff member
The stock banjo bolt is fitted to restrict the flow of oil to the turbo not the pressure, if you take too much flow away from that oil gallery you will loose flow from the centre main crank bearing and conrod bearing 3. Use the restrictor bolt,
Interesting I've just fitted (well kind of, I've just had to remove it) my 2871, however I've had braided lines made up for the oil supply as the original cracked and caught fire.

I doubt very much that there will be a restrictor in the line to the turbo now, my question is: is it vital to reinstall this restrictor to the line and if I ran without one, what damage could it create?

Cheers
 

The Doc

Moderators
Staff member
Reduced oil flow to the crank centre journal and cylinder 3 rod on start up is the main issue, nissan built it like that with multi million pound research and development facilities and sometimes people use the attitude that bigger is better when in this case it is not.

have you ever noticed that rod number three is the most common to fail on our cars, I wonder why?

it is also the same with the small tube by the distributor that links the crankcase breather to the rocker cover, it has a restrictor inside it to prevent oil from comming out of the sump ,people remove it to fit better breathers and then have oil filling up there catch cans especially on track.....I think they call that reverse engineering! It's use is so minimal to the engine for breathing (it's actually an emissions part to remove vapour from the crankcase, the breather part is done via the main rocker cover) that nismo actually blank it of with a core plug in the block on the rally cars.
 

fubar andy

Moderator & N/W Rep
Staff member
Reduced oil flow to the crank centre journal and cylinder 3 rod on start up is the main issue.
I think I've miss read what you posted, but are you saying that to run with out a restrictor in the oil feed to the turbo is ok or best to run with one?
 
Just to revive this thread.... Can anybody tell me please what size the restriction in the banjo bolt is as standard please?
The standard turbo is a journal bearing abviously but when you swap to a bb turbo (I now have GT3071R) aren't you meant to change the restrictor? since a bb turbo doesn't require as much oil as a journal bearing turbo.
Can someone please clarify if they know?
Thanks :)
 

PobodY

Moderators
Staff member
I think the point the Doc is making is that it's not a restrictor for the bearings on the turbo; it's there to keep the oil gallery full and the crank lubricated.

I think what you're asking is whether to go for a smaller restrictor with the BB turbo; I suspect that's OK because you're further reducing the flow, but the Doc should be able to give the definitive answer.
 

MarkTurbo

Well-Known Member
(I now have GT3071R) aren't you meant to change the restrictor? since a bb turbo doesn't require as much oil as a journal bearing turbo.
Can someone please clarify if they know?
Thanks :)
You don't need a restrictor, there's one built into the turbo ;-)

Edited to add, but use the standard banjo bolt.
 
Last edited:
You don't need a restrictor, there's one built into the turbo ;-)
That's what I thought mate but on the Garrett website they say it's down to you to ensure the maximum oil flow isn't exceeded by your engine at high revs. I have done many searches on the internet about this and there are so many different opinions. Garrett reccomends fitting an external resitrictor. Either way I have just ordered a scavenge pump for my oil drain as I have had so many problems getting a decent oil drain....consequently my new turbo is now smoking on boost. This new pump should do the trick!
 

MarkTurbo

Well-Known Member
it is also the same with the small tube by the distributor that links the crankcase breather to the rocker cover, it has a restrictor inside it to prevent oil from comming out of the sump ,people remove it to fit better breathers and then have oil filling up there catch cans especially on track.....
I've been there and done that :oops: Sometimes its best to look at things properly before you change them as they can often have secondary uses!
 
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