93FD3S

Yeap forgot the crush washer when I first put the motor back in. Made a nice mess. I also spoke with Majestic Turbo and they said my fitting was restrictive enough and anything smaller would probably damage the bearing.

CarbonR1

iTrader: (2)

This is not actually an easy question to answer, but I will try.

I checked on the recommended oil pressures for the GT35R, and they are:
minimum pressure at peak speed, 30.86 psi,
minimum at idle, 9.96psi.
minimum oil inlet bore of 9.53mm ID

As far as maximum oil pressure at peak speed, it isn't a question of oil pressure, but more so about oil supply volume. That means, you shouldn't restrict your inlet less than 9.53mm to get the recommended oil pressure because you may not be getting enough oil. With ball bearing units, too much oil can degrade the performance of your bearing system, because too much oil gets into the inner race of the ball bearing cartridge causing a parasitic drag on your *****. While a higher oil pressure would not really cause turbo failure, I wouldn't recommend going any higher than 50psi oil inlet, 70psi at worst using a 9.53mm oil inlet.

Oil seals are another thing. Oil blowby through the turbine and compressor is normally seen at specific operating ranges, usually seen when there is low compressor outlet pressures (idle) and low turbine inlet pressures (idle). This is because there is no pressure on the outside of the oil seal to help keep the oil inside. Again, this has more to due with oil amount, rather than oil pressure, because the oil pressure is significantly reduced inside the center housing.

-Kevin

CMonakar

13B-RX3

iTrader: (2)

I am in the process of trying to lower my oil pressure to the turbo also. It is not a BB turbo but Borg Warner recommends a max pressure of 55 PSI. I made a return style regulator for the turbo feed line and ran the return line into the filler tube so i could monitor flow on the return line. My engine runs 120 PSI of oil pressure over 4000 RPM and for several reasons i wanted to lower the pressure to the turbo. I set the regulator to bypass at 45-50 PSI. When i started the engine it was cold (thick oil) and it pegged a 60 PSI gauge. I let the oil come up to operating temp (180) and the pressure dropped to 40 PSI at idle. There was very little bypass at this point, the line just barley trickled. I raised the RPM to 3500 and the gauge pegged again 100+ PSI. The return flow at this point was VERY high. The supply flow was enough to exceed the flow of the regulator. When the turbo spooled though the pressure dropped down to about 55 PSI. I put a restrictor in the supply line (.125) to limit the flow where the regulator could control it. The pressure at idle didn't change, when i raised the RPM the pressure went to 65-75 PSI and when the turbo spooled the pressure dropped to 55 PSI again. I plan on putting a little smaller restrictor in the supply line so that the pressure remains between 40-55 PSI no matter what RPM or load.

So, even if you do decide to run a regulator you might still have to restrict the flow unless you have a VERY high flowing regulator that can control the volume of oil.

Allen