special tool

That ain't enough.
This is a 10 minute fix.

Rogue_Ant

Do you mean it is not enough vacuum? Or that his test was only a temporary solution? He did say it had absolutely no effect on the amount of smoke.


Rogue

special tool

Not enough vacuum - trust me.
Take it from the guy who has removed evrything on his car - YOU CANNOT REMOVE THE VACUUM FROM THE 951 CRANKCASE - CAN'T DO IT - DON'T EVEN TRY. Especially if you are not using a triple K turbo.

Don't even do it on a track car - because they'll throw your *** off the track.

Rogue_Ant

Ok, so how much vacuum is necessary (at idle)? And pull from what source, since he no longer has a niple in front of the turbo.


Rogue

cpt_koolbeenz

Knickers already in a twist...
I know exactly what the "vacuum" is supposed to do. Actually, there is a vent on the back of the turbo mount that goes to the AOS. That is where the "vacuum" pulls from NOT the crankcase or the steel drain line. The drain banjo is below the surface of the oil in the pan anyway. I'm not ignorant. Don't worry you are not the ONLY person on this board that has had their whole car apart....

I cannot hook it up like a stock car... I posted that already. How do you know I didn't get a good seal? WTF I suppose you were standing over my shoulder the whole time?


Now, if you (or anyone) could/would/wanted to help in a big way, you could measure the "vacuum" in the crankcase/AOS line for me and let me know what it is the way "Porsche designed it". I would be willing to bet that the vacuum that the crankcase sees on idle on a stock setup is next to nothing. That is my point.

tedesco

On my engine the crankcase return is diconnected and I have absolutly no issues at all. I cut it off because I did not want the oil mist to be returned and reducing knock resistance of the intake charge.
If I understood the explanations well than we are talking about the tube that connects the top of the oil separator back to the intake. In this case I would not understandwhy any vac should be build up because the tube connects to the intake INFRONT of the throttle butterfly. If you can measure anykind of vac I would say you air filter is crap. I belive the oil pump is probably the most significant vac geneating device of the engine if there is any.

tedesco

BTW Porsche designed it like that because in most countrys this is the only way to be emission legal. Not allowed to have a chatch can.

eclou

The only place which is going to experience vacuum under all engine loads is in front of the turbo. After/downstream of the turbo is going to swing from vacuum to boost, which will not help to evacuate the crankcase at all. The vacuum load in the crankcase will supposedly also help seal the piston rings and reduce the blow-by. There will always be measurable vacuum in front of the throttle butterfly - it is fundamental physics - how else is air going to be drawn into the throttle?

kasturbo

I solved my problem by going with a new turbo. Majestic could never get the seals right. I kept blowing out the center section. My catch can is now routed back to the maf pipe and I have no smoking issues with the new turbo.

ibkevin

14.7 psi at sea level.

cpt_koolbeenz

<<< In this case I would not understandwhy any vac should be build up because the tube connects to the intake INFRONT of the throttle butterfly. If you can measure anykind of vac I would say you air filter is crap.>>>

That is correct. At idle this should be true. There should be no vacuum unless the filter is restrictive. Under boost, there will be vacuum, which I'm not disputing.

So, still my point is, at idle, the turbo will not benefit from the crankcase being vented back to the engine. Which doesn't explain why my turbo is smoking at idle, other than the seals are crap...


I would be really interested if someone could measure the vacuum in front of the turbo at idle. It is possible there could be a little bit of vacuum <2inHg because the turbo does spin at idle... But I'm not counting on it.

<<<I solved my problem by going with a new turbo. Majestic could never get the seals right. I kept blowing out the center section. My catch can is now routed back to the maf pipe and I have no smoking issues with the new turbo.>>>

Thanks for responding por... Which turbo do you have now and from what company? Are you running a restrictor?

kasturbo

I'm now running the super 61 from Lindsey. No restrictor.

special tool

Yes, I was standing over you. I know what you did.
MY knickers are twisted because I know I could fix your car in 15 minutes by removing the obstinance.
Now put that vacuum back before I have to take off my shoe......

eclou

Does anyone honestly think that that the air in front of the throttle plate of a running car is not going to be below atm pressure? Am I taking crazy pills here?

MichelleJD

Mine was DEFINITELY the turbo