GiorgoS2k

We have started a turbo project based on a GT2560r *GT28r on NB 1.6lt miata. At this time all the "hardware" are installed and propably on Monday will fit the rest of exhaust, after the downpipe. We are running on stock engine with 305cc injector from Supra, with intercooler, innovate wideband and Greddy emange ultimate. After the first start as FI we found some oil leakage at the front of compressor housing. I forgot to inform you that we haven't tune it yet, we made some fuel correction just to get idle.
Any opinion about the oil leakage?
Does the turbo fail? (bought new...) or caused to untuned ECU?

After the exhaut installation will be able to based on wideband's data to create a better map @ Emanage...

PS: Can i find some maps to try? we are planning to get about 9psi

Thank you in advance
Giorgos @ Kom from Greece

ARTech

iTrader: (34)

Make sure you oil return line is free of kinks or any uphill bends. An untuned ECU doesn't have anything to do with it.

High oil feed pressure will make this happen as well, but if I'm not mistaken, all GT series turbos have an internal oil restrictor.

mafoose

Are you sure about that? I thought they made oil line restrictors specifically for ball bearing turbos.
I would call Garrett and find out...

LagunabluMX5

iTrader: (2)

do u have -3 or -4 oil feed line? I have a same turbo and was running a -4 for a short time. I found excessive amounts of oil in the ac piping and almost blew the oil seals in the turbo. If you have a -4 you will need a restrictor. I had mine made at a honda shop for five bucks. Hope it helps.

GiorgoS2k

Thank you for answers. let me show you exactly what i mean. As you can see at the pictures the oil return line -from my point of you- doesn't appear any bend. The turbo has oil restictor but the compressor side is full of oil...
If the turbo wasn't new i would be propably sure that the leakage comes from that.

Moreover, we connect an oil presure gauge to the engine side presure and we saw extremly high rates. At cold start the presure was bettwen 5-6bar (75psi-90psi (!) ) and after, reduced to 3-4bar (45psi-60psi)
Tomorrow we will connect the oil presure gauge to the tutbo side to see what preasure get the turbo (always using the restrictor).

Any ideas? do i need to go my brand new turbo for rebuilt???

mafoose

You show 2 banjo bolts/restrictors, do you have a restrictor on the outlet as well?
If so that could be it. The turbo outlet should be free flowing.

If that's not the case, I'd talk to whoever you bought this turbo from...

LagunabluMX5

iTrader: (2)

so is your feed line -3 or -4. This is what the fitting should look like

GT Oil Feed Fitting w/ Restrictor : -4 an GT BB Turbos [L-021] - $14.95 : Himni Racing, Turbocharger, Turbo, Garrett, Turbo Kit, GReddy, Mazda RX-7, HKS, Apexi, TiAL, TurboXS, TurboSmart, Flange, Turbonetics, Exhaust, Intercooler, ACT, Intake

ARTech

iTrader: (34)

^ he uses a banjo type fitting/restrictor, not AN like what most around here use. Both work fine.

Hard to tell from the pic, but the return line does appear to be pointing up slightly before entering the oil pan. Then again it could be the angle of the pic. What's the size on the return line?

LagunabluMX5

iTrader: (2)

did u figure out the leak?

GiorgoS2k

not yet...
Actually we don't have plenty of time to work.
After getting the oil presure rates at the block, now we are trying to found out what presure goes to turbo.

@Artech:
Difficult to say the exact size of the return line at this time because the car is rolling on wheels. The inside diameter of the line is about 10mm ->0.4in...

dustinb

I would say your return is way too small. You should be using a -10AN line, which should have an inner diameter around 1.5 inch if I remember correctly.

avante43

A -10AN line has an ID of about 9/16'. I dont think the problem here is the return being too small. Plenty of guys run -8AN lines which is around 3/8" ID with no problems.

From Garrett:
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.

So in other words you need to hook up the oil pressure gauge after the restrictor to see what kind of pressure you are getting.

musanovic

iTrader: (2)

Maybe the Return line going straight down needs to be angled a bit.

Stephanie Turner

If you have run the turbo, that amount of oil in the compressor side is completely normal. If the turbo has not been run yet, then a restrict or in the oil feel line might be appropriate.

A -8 or -10 oil drain line is also appropriately sized.
Stephanie