Japspec
Japspec Reader
3/7/21 12:09 p.m.

Hi everyone! I'm currently going through the turbo kit that I received for my NB Miata. The turbo itself is a chinese turbo, so of course the oil fittings that came with it are as well. The oil feed that goes on the turbo is a flange fitting. From my very quick research I just did, it seems that there are a lot of people who say the flange fittings leak severely and can cause oil starvation, and they recommend using a regular fitting instead (is that what they're called? New to this).

Now I know its a cheap turbo but I really don't want the turbo blowing on the dyno while its at the tuner. So I just wanted to come here for some insight; is it better that I buy a true fitting for the turbo, or will I be fine using the flange fitting? I'm not sure what other factors go into deciding which to use, so I can provide additional information if needed.

Here are some pictures of the flange fitting. Excuse my fingers; I had a disaster yesterday with RTV while attempting to seal my oil pan, so I have to reseal it:

https://imgur.com/a/NNcmzgd

bentwrench
bentwrench SuperDork
3/7/21 12:20 p.m.

ATP sells some o-ringed oil flange adapters.

Is the hole such that you could tap it for pipe or straight and use a banjo feed?

Japspec
Japspec Reader
3/7/21 2:06 p.m.
bentwrench said:

ATP sells some o-ringed oil flange adapters.

Is the hole such that you could tap it for pipe or straight and use a banjo feed?

Thanks! Do you mean the hole in the turbo itself? It looks to be threaded, so I can thread a fitting directly into it.

bentwrench
bentwrench SuperDork
3/7/21 2:30 p.m.

Note that the flanged fitting has an oil restrictor built in.

You could groove it for an O-ring.

malibuguy
malibuguy GRM+ Memberand HalfDork
3/7/21 3:55 p.m.

i would never trust a flanged oil feed personally.  Ive always threaded a fitting directly in or used a banjo fitting depending on the situation

Japspec
Japspec Reader
3/7/21 7:43 p.m.
bentwrench said:

Note that the flanged fitting has an oil restrictor built in.

You could groove it for an O-ring.

Thanks! I guess I could try grooving for the O-ring...I just know I will mess it up if I try and it will leak anyway. Are oil restrictors usually all the same size, or are there different sizes? I have no idea what size the restrictor hole is for this flange fitting, since I didn't get any kind of specs on that. I do know that the turbo is a replica of a Garrett T3.

malibuguy said:

i would never trust a flanged oil feed personally.  Ive always threaded a fitting directly in or used a banjo fitting depending on the situation

Gotcha, thank you! Do you thread the fitting in with some high temp thread sealant on it? I'm not sure how hot that part of the turbo system gets, but I was thinking that it would be a good idea to use that on the fitting for the oil feed. 

malibuguy
malibuguy GRM+ Memberand HalfDork
3/15/21 5:15 p.m.

In reply to Japspec :

I dont, but Ive seen others that have used thread dope.  Usuaully there is a copper Oring like you have on brake flex hoses

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
3/15/21 5:36 p.m.

That part of the turbo gets very hot. And the oil is at 60 psi+, definitely not the place for a flat flange.

Find out what the thread is, that will determine how it's supposed to seal.

We don't use restrictors on our turbos, never have.

ShinnyGroove (Forum Supporter)
ShinnyGroove (Forum Supporter) HalfDork
3/15/21 8:39 p.m.

I used a flange fitting like that on my T3/T4 churbo, never had an issue with it.  Car saw a lot of track duty and I broke just about everything else, but never a problem with the oil feed. 

Japspec
Japspec Reader
3/15/21 9:44 p.m.

 Keith Tanner said:

That part of the turbo gets very hot. And the oil is at 60 psi+, definitely not the place for a flat flange.

Find out what the thread is, that will determine how it's supposed to seal.

We don't use restrictors on our turbos, never have.

Thanks! I don't know how different the FM supplied turbos are to a chinese T3 (besides the obvious quality differences), but I contacted the kit manufacturer (hes a one man shop, might be able to guess who it is) and he said he hasn't ever had a problem or heard of one with the flange. I could just get a fitting and be done with it, just not sure what the restrictor size is.

ShinnyGroove (Forum Supporter) said:

I used a flange fitting like that on my T3/T4 churbo, never had an issue with it.  Car saw a lot of track duty and I broke just about everything else, but never a problem with the oil feed. 

Thanks! Did you source the turbo yourself, or was it part of a kit?

bentwrench
bentwrench SuperDork
3/15/21 10:24 p.m.

The flange sealing surface is AFTER the restrictor = no pressure (~crankcase pressure)

I'd venture that if the turbo came with a restrictor, you may want to retain it.

Japspec
Japspec Reader
3/16/21 12:16 a.m.
bentwrench said:

The flange sealing surface is AFTER the restrictor = no pressure (~crankcase pressure)

I'd venture that if the turbo came with a restrictor, you may want to retain it.

Got it, thank you! I didn't know what kind of pressures there are at different points, so thats good to know. Yeah, I figure the restrictor was included in the flange for a reason, so might as well run with it. Hopefully it all goes well.

ShinnyGroove (Forum Supporter)
ShinnyGroove (Forum Supporter) HalfDork
3/16/21 6:42 a.m.
Thanks! Did you source the turbo yourself, or was it part of a kit?

Sourced it myself from Ebay, I think the brand was DNA Motoring. I did use a restrictor with it, can't remember what size. 

Japspec
Japspec Reader
3/16/21 7:55 a.m.
ShinnyGroove (Forum Supporter) said:
Thanks! Did you source the turbo yourself, or was it part of a kit?

Sourced it myself from Ebay, I think the brand was DNA Motoring. I did use a restrictor with it, can't remember what size. 

Gotcha, thanks! It sounds like I should be fine with the set up I was sent, so I'm hoping for the best.

Japspec
Japspec Reader
3/22/21 2:46 p.m.

So after thinking if over for awhile, I may just buy a fitting rather than the flange. Going to buy a .035 and compare it to the opening on the flange. When looking at restrictors though, I saw two different types:

 

1.) Restrictor on the AN side of the fitting: https://www.amazon.com/Boost-Monkey-Turbo-Restrictor-Fitting/dp/B078M3MDP5/ref=pd_sbs_4?pd_rd_w=yOsiI&pf_rd_p=651d64d1-3c73-45b6-ae09-e545600e3a22&pf_rd_r=E83YGYXZTEXS64DC73TQ&pd_rd_r=49a747cd-07b5-48e2-9538-ce07d636c023&pd_rd_wg=9Lmg3&pd_rd_i=B078M3MDP5&psc=1

 

2.) Restrictor on the non-AN side of the fitting: https://www.amazon.com/PULSAR-16-24UNF-Restrictor-Bearing-Turbo/dp/B08F7NV16L/ref=sr_1_7?dchild=1&keywords=.035+oil+restrictor&qid=1616442286&s=automotive&sr=1-7

Besides the price, is there a difference in the performance of the two, or does it not really matter which end the restrictor is on? My flange type has the larger opening on the AN side and then the small restrictor opening on the flat flange surface.

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