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The only car that I've had it be a problem was on a ~750whp drag car. He'd get about 10-12oz in the can after 6-7 passes. I ditched the recirc setup, and pcv line to the manifold. Drilled the valve cover for 1/2' pipe, and modded the catch can to have two 10an fittings and two VTA filter on top and ran two 10an lines from the valve cover. Now he gets 1-2oz of oil in it after 6-7 passes.
I don't think its the rear vent, I think one 10an line isn't enough of a vent and crankcase pressure is still pushing oil out.
The only car that I've had it be a problem was on a ~750whp drag car. He'd get about 10-12oz in the can after 6-7 passes. I ditched the recirc setup, and pcv line to the manifold. Drilled the valve cover for 1/2' pipe, and modded the catch can to have two 10an fittings and two VTA filter on top and ran two 10an lines from the valve cover. Now he gets 1-2oz of oil in it after 6-7 passes.
I don't think its the rear vent, I think one 10an line isn't enough of a vent and crankcase pressure is still pushing oil out.
I got rid of the recirc on the back of the valve cover too. Just a -10 into the catch can to vent excess pressure. I still run the -6 on the driver side to the intake.
I have the driver's side outlet drilled out for a -10 that feeds a recirc can going back to the preturbo intake. The rear pcv line is still stock, been thinking about changing that out because I'm still seein my dipstick move a bit. It's not being shot out of the tube but it'll be pushed out 1/2" after a session.
So both of you are VTA, taking into consideration that the system as a whole likes being under vacuum at all times.
Mychailo proved you can not create a vacuum under boost logging valve cover pressure with various changes. Thats a pipedream without having something extra pulling a vacuum.
The lowest he achieved was with VTA. With a PCV setup, of course the port at the back is blocked so only the port going pre-turbo is pulling any pressure out. With the rear valve cover port opened but run to a catch can then over to the intake, it helped but the line length causes a flow loss. Best was just running it to a catch can and letting that port vent.
Can you clarify the last post, Mychailo's experience...
Best/lowest pressure was with both ports VTA.
But if you used PCV Setup, rear port going to pre-turbo-intake: how was that?
I have drilled-valve-cover with 10AN through PCV into intake and rear 10AN port to pre-turbo-intake.
This I hope will allow for some vacuum under all circumstances being applied to VC, to at least minimize pressure build.
Can you clarify the last post, Mychailo's experience...
Best/lowest pressure was with both ports VTA.
But if you used PCV Setup, rear port going to pre-turbo-intake: how was that?
I have drilled-valve-cover with 10AN through PCV into intake and rear 10AN port to pre-turbo-intake.
This I hope will allow for some vacuum under all circumstances being applied to VC, to at least minimize pressure build.
This is exactly what I did, and thought. However, my reality is that under racing conditions the following combnation is happening:
1. The RPM based suction created by the pre-turbo line going to the intake pipe is creating a "suck zone" in a rather unbaffeled part of the VC.
2. The RPM based oil sloshing in the valve cover is being pushed to the back by your G's from accelerating
3. This moisture/oil is getting sucked into the catch can, as designed right. But for any duration it takes precious oil out, but also moisture out. Double edged sword. Unless the moisture is actually being introduced by this "sealed" setup. When I drain the catch can it's obviously runny. My friends refer to it now as the "Oil recycling system" or ORS to sound like a porsche lol.
4. Doing half a day of dyno pulls or any other non-track driving yields almost no oil in the catch can.
mines dash 10 and i have a squillions llamapower and i never push ****all into my catch tank. as mentioned sounds like its being pushed out under pressure. bet ya if you opened it out to dash 10 it will stop,
Side note: have you got the stock baffles still in the rocker cover?
Can you clarify the last post, Mychailo's experience...
Best/lowest pressure was with both ports VTA.
But if you used PCV Setup, rear port going to pre-turbo-intake: how was that?
I have drilled-valve-cover with 10AN through PCV into intake and rear 10AN port to pre-turbo-intake.
This I hope will allow for some vacuum under all circumstances being applied to VC, to at least minimize pressure build.
The conclusion from the bit of testing Mychailo did was that no amount of suck thru a couple small hoses is going to balance out the air pushed into the crankcase via blowby. There were other methods discussed like an exhaust venturi PCV but thats not legal in most classes.
With his test, logging actual crank case pressure, he found venting both sides showed the lowest overall pressure of course because it just cant build. The PCV system working essentially blocks the rear port leaving side port to do all but its too small to vent enough.
If you have a pair of -10 or greater on the side of the manifold to the intake, I suspect that would be enough to fully release the pressure in the crankcase but dont think you're going to pull any real vacuum. Thats not how flow works.
The simplest solution is still to run the -10 port at the rear to a catch can and -6 port to the intake on the intake. Under boost that is an 8x increase in venting area over the OEM 8mm line. Remember, the rear port is blocked by the OEM PCV system under boost, this allows it to now vent and do something in boost.
The conclusion from the bit of testing Mychailo did was that no amount of suck thru a couple small hoses is going to balance out the air pushed into the crankcase via blowby. There were other methods discussed like an exhaust venturi PCV but thats not legal in most classes.
With his test, logging actual crank case pressure, he found venting both sides showed the lowest overall pressure of course because it just cant build. The PCV system working essentially blocks the rear port leaving side port to do all but its too small to vent enough.
If you have a pair of -10 or greater on the side of the manifold to the intake, I suspect that would be enough to fully release the pressure in the crankcase but dont think you're going to pull any real vacuum. Thats not how flow works.
The simplest solution is still to run the -10 port at the rear to a catch can and -6 port to the intake on the intake. Under boost that is an 8x increase in venting area over the OEM 8mm line. Remember, the rear port is blocked by the OEM PCV system under boost, this allows it to now vent and do something in boost.
Ya your wording is not flowing lol. "The simplest solution is still to run the -10 port at the rear to a catch can and -6 port (from where, VC side?) to the intake on the intake (manifold or intake pipe?).
This is what I'm running, the only difference is I'm on the V1 hoses which are 6AN
Ya your wording is not flowing lol. "The simplest solution is still to run the -10 port at the rear to a catch can and -6 port (from where, VC side?) to the intake on the intake (manifold or intake pipe?).
This is what I'm running, the only difference is I'm on the V1 hoses which are 6AN
Yeah, this setup is totally good and fine. But its not giving you a vacuum in the crank case. Its just preventing crankcase vapors from getting into the engine bay and drawing a tiny bit extra vapor out than just being vented.
For competition yes, absolutely. When you're getting 1-1.5 events out of a set of tires you can easily get into $5-8k a year just for tires.
But he's just talking about HPDE, way different world there haha
ayoustin: yes. In a year I may do one TA event, about 3 HPDE, and any number of autox events. My tires seem to last through the year. For my situation, an OEM shortblock is just fine, as well as a modest tire budget. For me, having to refresh a forged short block just wouldn't make much sense, since I'm only ever racing myself. I'm still more in fun > competitive mode. As I think I mentioned earlier, if I changed to competitive > fun, then I'd possibly have to rethink things.
I see the crank case ventilation issue still hasn't been resolved
Jun 26, 2019, 08:27 AM
