Another Oil Feed/restrictor Question

[limpus]

Quick question for the more technically inclined:

I'm putting a HKS2535 onto my rb20 tomorrow...I know that ball bearing turbos usually require a restrictor in the oil feed...my question is since the the stock turbo on the rb20/25 is ball bearing anyway...will i still need an oil feed restrictor?

I'm using a braided line that came with the turbo and I'm unsure of what the internal diameter of that line should be...would the standard holes in the banjo bolts be enough to restrict the oil flow for the new turbo?

Cheers...

[Sydneykid]

Quick question for the more technically inclined:

I'm putting a HKS2535 onto my rb20 tomorrow...I know that ball bearing turbos usually require a restrictor in the oil feed...my question is since the the stock turbo on the rb20/25 is ball bearing anyway...will i still need an oil feed restrictor?

I'm using a braided line that came with the turbo and I'm unsure of what the internal diameter of that line should be...would the standard holes in the banjo bolts be enough to restrict the oil flow for the new turbo?

Cheers...

The oil flow restrictor is in the inlet fitting in the turbo core.

Supply pipework size is irrelevant, ie; the restrictor is smaller than the smallest pipework you could buy.

Cheers

[limpus]

Thanks SK...so am i right to say that i can just go ahead and bolt everything up as the restrictor i speak of is not required as its already in the core?

[r33_racer]

yes thats what he is saying. Everything will work properly, dont worry about it.

[limpus]

Good to know...thanks fellas...

[WilYawn]

I bought my HKS GT2510 used but rebuild off eBay and it came with a restricted bolt. Do I need it or is the restrictor build in the housing?

[Wheezy]

The oil flow restrictor is in the inlet fitting in the turbo core.

Supply pipework size is irrelevant, ie; the restrictor is smaller than the smallest pipework you could buy.

Cheers

SK is this the same for the garrett GT series turbochargers? I assume so. ALso in regards to the inlet line, I was thinking it ocould be a good idea to make it curl like the factory does IIRC, or would that restrict the flow of the oil and starve the turbo then? (I think Nismoid did this on his RB25)

cheers

-Jez

[T04GTR]

ball bearng turbo. use -3 hose to it.

if its bush use -4 if its highflowd use -6

[Wheezy]

Excuse my dumbness, WTF is -3 hose? And it still doesnt answer my question, does the garrett have a restrictre built in?

[tridentt150v]

SK is this the same for the garrett GT series turbochargers? I assume so. ALso in regards to the inlet line, I was thinking it ocould be a good idea to make it curl like the factory does IIRC, or would that restrict the flow of the oil and starve the turbo then? (I think Nismoid did this on his RB25)

cheers

-Jez

The oil is under pressure, you can't restrict the flow pigtailing it. You can only stop/restrict the flow if you kink it. If you use braided line there is no need to pigtail it, the pigtail is only there to allow some flexibility [given that it is a hard pipe ie steel and inflexible] for vibration between the block and the turbo. A braided line is already flexible so caters for this.

I would avoid having the hose to short - a tight fit, but I would also avoid having the hose too long, allowing it to flop around and wear on other parts. I would think that if it was around 50mm longer than a straight line fit it would be ideal.

[tridentt150v]

Excuse my dumbness, WTF is -3 hose? And it still doesnt answer my question, does the garrett have a restrictre built in?

3mm ID

If its a late model [modern] unit ball bearing then yes it should

[dangerman4]

GCG supplied me with a restrictor that pushed into my -4 line where it screws into the block.

but the hole in it was only about 1mm.

i would check with them if i was you. tell them the no. on your turbo and they will tell you if you need one or not.

the restrictor looks similar to a head oil feed restrictor.

to me 3mm sounds like you dont have a retrictor at all.

[tridentt150v]

But its supposed to be in the turbo? Not the block?

Does this mean you can't see it? I've got my GT3076 in my hand and the only restriction I see is the 3mm hole/seat that the banjo bolt tightens into/onto. I don't see any other smaller hole.

The bolt shown above would not work, the brass insert would be sitting on the seat, not ver it.

[Wheezy]

I will have a better look at the turbo and call GCG, they built it anyway. But yer it was built this feb, so its a brand spanker.

[Cubes]

Not sure how applicable it is to the RB's.

GCG appear to believe it is?

GCG supplied me with a restrictor that pushed into my -4 line where it screws into the block.

but the hole in it was only about 1mm.

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

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.