TOTALLY STUMPED!! ....can an R33 GTR be driven safely on one turbo?

[Skym]

Oil in the intake pipe before turbo is normal and is from the PCV system, especially if running 1 bar.

Usually it takes constant rpm for the oil to reach the intake pipe infront of turbo (2x hard laps on a racetrack would do it). Why? as the oil moves to the head under high rpm and doesn't drain back as quickly as it should through the stock oil drains. That's why a restrictor is fitted to the oil feed to the head to reduce the amount of oil getting to head. Best way to eliminate it is a dry sump setup.

Driving normally and reving to 1 bar for a short period of time most likely wouldn't result in much oil in the intake pipe before turbo as there not much oil getting to the head.

Look at how a stock oil pump works and it will make sense, as the higher the revs, the more oil it moves until the pressure relief valve opens. Gets worse with aftermarket oil pumps that move more oil hence the oil restrictors are needed to reduce amount of oil to the head, enlarge the sump capacity to suit the oil pump that is being used as it moves more oil.

Turbo failure on intake side shows up with a pool of oil in the bottom of the intake piping after the compressor housing (usually the 90 degree elbow). There usually is no smoke, just oil coating inside of intercooler, intake piping, BOV, Idle valves, etc. They would need to be cleaned after changing the turbo.

With intake side turbo failure you'll get a whistling sound around 0 on boost gauge (compressor wheel touching compressor housing) and eventually a wacking sound when the bearing really starts to fail on compressor side of turbo. The exhaust wheel is usually ok. Sometimes the whistling is an intake airleak after the turbo, so that has to be eliminated first.

Exhaust side oil seal failure would put oil into exhaust as a out of balance shaft (due to bearing wear) can take out the rear oil seal and that's where the cloud of white smoke from the exhaust comes from. But usually that results in the ceramic exhaust wheel hitting the exhaust housing and going down the exhaust if under throttle when it shatters. The ceramic exhaust wheel usually ends up in the middle of exhaust or not to be seen if makes it's way out of the exhaust (no cat). If backing off throttle when the ceramic exhaust wheel shatters (hitting the exhaust housing) some of the parts of the ceramic exhaust wheel can enter the engine via the exhaust ports (rare that it happens, but has happened).

These are only possibilities and need to be checked, eliminated.

I think is just normal blowby and to avoid getting the oil into intake, just drop the boost level back to the internal wastegate spring pressure (lowest boost level you can run with a boost controller).

RB engines are known to produce alot of blowby when running higher boost levels and the sump gets full of blowby gas. Most bypass the smaller internal oil galleries (gets worse with the smaller oil restrictors) and run a vacuum hose from the sump (above the oil level in the sump) to catch can, then it goes into intake from the catch can to relieve the sump pressure / blowby. This is not new and has been used on many racecars for years, including Group-A, N1 GTR's, etc.

Edit: Also the catch can is connected to the exhaust side breather or both breathers / fittings on the top of engine.

[Bruizer]

Wasn't offending. I just thought I'd mention that with you past history with skylines, you should fix it before it get's worse. I'm clueless too don't worry. I've been throwing money at a running gtr since 2009 and it hasn't run since 2010

[judasentinel]

Wasn't offending. I just thought I'd mention that with you past history with skylines, you should fix it before it get's worse. I'm clueless too don't worry. I've been throwing money at a running gtr since 2009 and it hasn't run since 2010

And I thought my problems were bad....

I don't get offended easily, if at all. I was merely responding to your comment, which now I understand the meaning of. My apologies if it upset you. I see my Skylines as my kids, and you just cannot give up on them EVER (at least that's how I am). Just like me, and Carter and Ben and a few others, you have been around on GTRC for far too long for me to take offence from a fellow GTRCer. No sweat.

I think my issue comes from this deep desire to understand the WHY aspect of things, as i am not satisfied being told what something is....I understand the mechanics of things, how turbos work, and how our engines are supposed to function. What stumps me is when everything is working as it should, yet the results are not there; or when something that is NOT supposed to work, IS working. Case in point, the oil in the intake pipe situation. My questions was why it was happening only in the rear turbo intake pipe and not the front one, if it is related to BOVs, which connect to BOTH turbos through the Y-pipe. And short of admitting that the rear turbo is either shot or on its way out, there seems to be no other explanation to it. But then, how come it is still boosting great, not hesitating, not smoking out the exhaust, etc..? The two points seem mutually exclusive, but yet they are both happening - the oil in the intake piping (only the rear one), AND the perfect boosting.

It is likely that the rear turbo IS leaking oil, but is not broken. I doubt the exhaust wheel broke, as I would have crazy smoke coming out of the exhaust...one RB26 turbo is not large enough to boost to 1 bar on its own when the other is shot as it will interfere too much with the pressure. That's just my opinion. Like an a$$hole, everyone has one and I could be totally wrong about it.