Guys I have a small oil weep on my right hand turbo, I though this was just the seal was worn and on its way out.

I have since spoken to turbo teckniks (at a car show here in the UK) And the guys off the stand used a cut away version of the GT2871R to show me the seal system and it uses a piston ring style seal that uses exhaust pressure from the inside of the back housing to pressthe ring down on to the exhaust wheel shaft.

He said this might not have enough pressure to seal the ring full due to a large exhaust?!? This sounds like it makes sense to me but I have never heard of an exhaust TOO BIG for a turbo car before??

I have APS 3.5" DP's and a dual straight through 2.5" system.

He said adding a small amount of back pressure may help it seal tighter and stop the oil weap?

He also said the "sweet spot" for the GT2871R's is about 1.2-1.4 bar! Any one know what the turbos will do on the zed motor? Im thinking they would be out of puff at 16-17psi??

Thanks.

 

the only thing that is gonna cause oil leaks are too much oil pressure or not a big enough drain hose.

What size is your restrictor? Best solution is to plumb a oil pressure gauge into the oil feed at the turbo.

I just went through fixing a weeping seal.

 

The drain hoses are bigger than the stock APS ones and there better loacted back into the sump above the oil level and on a nice downward angle.

The only thing that I can think of is too much oil pressure like you said. The restrictors are what ever size APS spec for them im not sure?? Ill look into what sort of pressure the tubo oil feeds are soon. What sort of pressure is ok for feed lines??

 

I believe Garrett recommends no more than 40-50 psi max at their turbo inlets.

I put in a Forced Performance inline turbo oil filter and it seems to have helped (I was leaking a little into the compressor side charge piping). I have the outlet machined to .05" and that serves as a restrictor feeding both turbos (Garrett recommends .035" I believe for each turbo). On start up I see 50 psi, but when hot at idle it drops down to 6 psi.

EDIT: exhaust and intake piping pressure is used to seal Garrett turbos and will exacerbate seal problems if not initiate them. I ran at the airstrip with a coupler sitting loose on one turbo and I leaked a lot more oil into that side... That stopped as soon as I cleaned it up and put the coupler back on (advantage of having two ICs is I can see cumulative oil output from each compressor).

 

When you say they are weeping, do you mean under pressure..(i.e. as oil pressure comes up)? Or is it happening at different times?

Tom

 

Like this mate, Only at idle revs can I see the smoke like this and it clears after I rev it once, Just must pool some oil somewhere that gets blown clear?? Ps. the knocking on the vid is my diffuser not the motor! lol..

[youtube]v9AuR3hvRzs[/youtube]

 

definitely isn't your exhaust.

your seals may just be going out. Personally, I wouldn't mess with the restricteos regardless what you may be being told.

almost exactly 550 whp ( I think 551 specifically) on GRD's dynapak at 15.1 psi. I'll see 16 or so on the street sometimes. this is on a 9:1 motor, 2.5" APS exhaust, GTM stage 1 turbo cams tuned on 92 octane.