i just went to home depot today and bought the home made catch can kit.. hopefully i have enough day light tommorow to install it.. thats my first step to solving my smoke problem

https://my350z.com/forum/engine-driv...-new-post.html

 

Catch can changed nothing about my smoke issue. I still get it at the same (in)frequency and amount as I did before I put one on.

That being said, it certainly does catch oil and crankcase moisture and is a worthwhile mod. But I think the fact that 9 out of every 10 posts I see about oil smoke upon decel are regarding the TN kit, leads me to believe the issue has something to do with TN's turbos themselves. And yes, I realize that there are more TN kits running around then the other kits so that will account for some of it, blah etc etc.

 

i have a greddy kit.. mine is at WOT

 

Yes I know. My point was that TN people having smoking issues should not run out and purchase catch cans thinking that will fix their problem (though I do advise getting a catch can for other reasons).

I am thinking one of these would be more effective. I hate to be the guinea pig, but....

 

What is that part?

 

Oil restrictor.

 

so you think this is due to high oil presure?

the worst part is that my wife does not know that I install a turbo on my car and yesterday she mention something about the smoke because she was fallowing me on her car (I keep the rpms under 4k to sillence the BOV)

 

Its my opinion. I have gone thru my setup several times and that is really all I'm left to suspect. I did all the work on my car so I know it inside and out, and have tried different PCV setups, rerouting the oil drain, using different oil weights, did a compression test, installed a catch can, etc.

I am left to believe it is a combination of residual high oil pressure on decel combined with the nature of turbonetics turbo seals.

 

hope you are right I want this thing running good... Good luck if works let me know .. you will save my A$$ big time

 

It could be high oil pressure, but pressure is usually highest under boost, not decel - so your symptoms are a bit odd. As I recall you have the lower plenum sucking out crankcase vapors at idle, correct? That should be eliminating any crankcase pressure build up under decel.

I would replace the PCV to make sure that isn't clogged up - $15 from your local Nissan dealer.

 

Even after you install the catch can, you may see smoke from pooled oil in the plenum and intake piping, IC, etc. If you do decide to clean it, I wouldn't spend a lot of time on it. It takes days for it all to move downstream. Wait a few weeks, then clean it all out if the smoking actually stops. I made the mistake of cleaning my ICs out a little too early - PITA.

 

You are correct regarding my PCV system setup. I think I will replace the PCV valve, as it is one thing I havent done yet.

I see what you're saying about oil pressure, but this is my take on it:

-during a WOT pull, oil pressure reaches its highest point.
-when you let off suddenly and begin to decel, you stop spooling the turbo quite fast, however, oil pressure does not drop as fast.
-I think that its during this time window, when oil is still being pumped into the turbo at a high pressure, but the turbo is not spinning extremely fast and is not evacuating the oil fast enough, that it passes oil thru the seals.
-I have noticed that when I back out of the throttle, instead of just letting off sharply, that it never blows smoke out the exhaust.

I welcome any thoughts on this theory of mine

 

I am not sure that the turbo bearings spinning is what pumps oil through the turbos - rather I believe it's the oil pressure generated by the engine's oil pump. Nevertheless, it could be that a drop in exhaust pressure when you let off the gas sharply draws the momentary high oil pressure in the turbo out through the turbine seal. The drain line should provide less resistance than the turbine seal though. It sucks if it doesn't!

Do you have a water cooler turbo? It could be that you have experienced oil coking. Trying an oil restrictor is worth a shot I suppose given that the alternative is a rebuild anyway...

Ball bearing turbos don't require much oil. If yours is the metal brush type, then that operates on the principal of having a thin layer of oil over a large surface area of the shaft, so I'd be a little worried just arbitrarily sticking in a restrictor for one of those. Good luck!

 

smoke no smoke.. .. it looks gorgeouss going up RT35 hahah

 

My turbo is the watercooled version, and its ball bearing. Also, this turbo only has about 2k miles on it, so I doubt coking is an issue.

 

Yep, I agree. An oil restrictor sounds reasonable.

 

I went ahead and ordered a .060 oil restrictor. I will let you guys know how it goes.

 

oh man, im excited. let us know asap.

 

Yep I will. Hopefully it will get here by friday so I can get it installed in time for some racing I'll be doing sunday.

If the .060 doesn't fix it, I will try the .035 that ATP recommends on GT28/30/35 turbos. I figured I would start with the largest restrictor and work down. If neither works, it would seem our issue is elsewhere.

 

Does the kit come with any kind of restrictor? I know the JWT kit has a restrictor with the kit - don't know the size though.