Turbo Oil Feed For Single Conversion

[leeroy_25]

I am building an RB30/RB26 ad running a single turbo setup.. I have the series 1 block which does not have the oil feed in it for a turbo so was planning to take a feed from the oil pressure switch. What I noticed though is I think most the turbo takes a -4AN (1/4") bore fitting where as the oil switch is only 1/8"NPT Will I get sufficient oil for the turbo from here? Looking in side the turbo it seems the oil holes to the bearings are only very small but I want to be sure.. I guess I could open up the oil switch hole in the bock to take a larger fitting but only want to do that as a last resort as the engine is pretty much built and I don't want to risk getting metal swarf inside the gallery when drilling and tapping it out!

Advice please.

Thank you

Lee

[The Dan]

The oil pressure sensor gallery is adequate to feed the turbo with enough oil. Just get the biggest ID size you can in there. The turbo (depending on type) should have the restrictor built in or at least run a restrictor smaller than 1/8th anyway...common restrictor sizing for ball bearing is 0.8-1.0mm and for journal bearing around 1.5-2.0mm...so both are much smaller than that feed line.

[leeroy_25]

Hey man, Must picked thsi reply up! Thanks for the info.. I have a journal bearing turbo by the way.. I'll try and bore out the centre of the tee piece a bit to open it up some in that case and it should be sweet.

Cheers

Lee

[The Dan]

With journal bearing turbos you have to be careful. They are the leas likely to have a restrictor in place. I would just get a normal fitting, hook it all up and measure the oil flow from the drain pipe at idle. You should see about 1 - 1.5L/min. You will be wasting your time opening up the fitting hole if you just have to put another restrictor in there anyway.

The restrictor is best placed nearest the turbo also.

[leeroy_25]

Thanks for the reply again.. It's a Holset turbo if that helps?

I looked inside the tubro where the oil fitting goes and there are two smalle holes about 2-3m diameter.. presumably one going to each end of the turbo? Does that sound reasonable?

It would be ideal to have this sorted before I put it in the car as there won't be much room for work once it's in!

If I don't need to open out the hole in te block it would be better.. But then at the same point if I am not going to get enough flow from the smaller hole I really need to know so I can open something up.. or are you fairly confident the 1/8" oil pressure hole is an adequate feed size as it is?

Thank you

Lee

[The Dan]

You don't have many options I'm afraid.

What is the part number of the Holset turbo you have. I will let you know if there is a restrictor built in or if you need to run one and what the oil return flow should be. It's up to you to do the rest. There is no easy way to set this stuff up. All you can do is use the information you are given and make the best with what you have. Fit the turbo, run the oil line, test the flow amount from the return at idle and if it needs a restrictor, then put one in...it's simple to do. If it flows enough then leave it be.

Job done.

Get me the part number or serial number on the turbo and I'll give you the information you need.