CCV and Valve Cover Breathers

[Skidmark]

I've got a paxton supercharger and the CCV/PCV is using the factory routing straight into the intake manifold. Since the intake manifold sees positive pressure some of the time, does it make more sense to route the CCV line to the intake before the supercharger? The Paxton kit came with a PCV (one way) valve so the pressurized air does not go from the manifold into the block, but do I even need the CCV since the valve cover breathers are present?

I've also got a 3-port catch can setup installed with the valve cover breathers routed to one of the input ports and the output port routed to the intake before supercharger. Could I route the CCV into the 2nd input port into the catch can?

[GTS Dean]

I've been running various configurations of catch can plumbing and PCV control on my car since last summer and have learned quite a lot in that time based on 4 days at Road America and 3 days at COTA, along with several hundred miles of street driving and 3 sets of spark plugs. The valve cover vents are primarily for providing fresh makeup air to the crankcase. About 98% of Gen 2 oil control problems are from the CCV side. Your CCV pushes oily blowby out and is metered by the PCV valve or orifice device before entering the intake manifold. That's where you need to focus the catch can plumbing.

Highly modded engines need substantially different flow control than afforded by any stock PCV valve. I would strongly recommend the M/E Wagner tunable PCV valve. https://mewagner.com/ It can be set up either as 2-channel Dual Flow (Idle/Cruise) or Orifice Mode (both adjustable). Either one allows you to control the flow rate back to the intake manifold and it has backfire/boost check valve protection. A bit pricey, but simple to plumb and allows individual tuning for your application - including boosted.

The top photo shows the new block vent plumbing out to the front crossmember bulkhead fitting. For the valve cover breathers (clean makeup air side) I reworked the stock plumbing and moved the outlet tee to a central location and plumbed it to the small Mishimoto catch can. I removed the bronze filter for unobstructed flow. The outlet loops around back to the engine air cleaner nipple.

The lower photo shows the 8oz Mishimoto baffled catch can mounted to the same boss that holds the hood spring bracket. The outlet comes back to center, through the Wagner PCV valve and back to the manifold inlet tee.

[Skidmark]

Thanks, Dean - after my last (and only) track day, I had a ton of oil in my intake from the valve cover breathers. Since the CCV was routed to the intake manifold, I couldn't tell how much oil would have escaped from there.

So could I safely route the CCV/PCV and valve cover breathers to the same catch can that has 2 filtered and 1 clean air port, or would it be negative in any way to have the valve covers breathers and CCV/PCV be able to cross air between themselves?

[GTS Dean]

The conventional engineering wisdom is to have them separated. Otherwise, you have pressure/vacuum conflicts that are all but impossible to diagnose. Mr. Acoustics and I have done our own work individually and arrived at the same basic truths about where the oil comes from. When I had the stock PCV setup with the small catch can plumbed to the valve covers and air cleaner, I caught maybe 1oz in it the whole time at Road America, but the engine was ingesting almost a quart per track session. With the setup in the photos below, the car filled the little can in 1.5 laps at COTA, then went straight to the intake.

The last time at COTA, with the big Mishimoto can and the Wagner valve, I caught 8-10oz every session and poured it back in the motor. No oil got to the new PCV valve, so the manifold was cleaner. I probably could return the valve cover plumbing back to stock, but I'm pretty proud of my small catch can setup despite the fact that it now catches virtually zero oil vs the CCV can.

https://driveviper.com/forums/threads/24279-Prepping-my-GTS-for-the-Track

[GTS Dean]

If I was do do all this again on a Gen 2 from a clean sheet of paper, I would use this ECS catch can with their universal bracket and plumbed to the block vent only. It uses AN10 o-ring boss fittings which you can find anywhere in any angle you choose. I think the best mounting spot would be near the passenger side bend in the shock tower cross-brace. Because of my very large air box, the Mishi was a challenge to locate and mount. Plumbing was problematic due to its M20x1.5 metric fittings.

https://www.ecstuning.com/b-ecs-parts/ecs-tuning-baffled-oil-catch-can-8oz/003779ecs05-02~a/

[Skidmark]

What's the benefit of spending hundreds of dollars on a catch can vs an Amazon $20-$30 knock-off?

[GTS Dean]

America vs China?

[Dan Cragin]

On the Gen 2's, I have found it best to completely remove the and plug the PCV crankcase vent under the intake (for track only cars). On hard braking oil gets pushed up in the timing case cover and
oil gets sucked into the intake. A catch tank can be added if the PCV needs to be retained for emissions.

I typically vent the valve covers from the top with 2 3/4 inch lines to a breather tank. The size of these lines allows the crankcase to vent without hardly any pressure and the breather tank seldom
needs to be serviced.

Just my experience, yours may differ.

[Skidmark]

My car is mostly street (if it gets driven) so I think it would be a better idea for me to retain the CCV/PCV. I'm going to add another separator to that circuit now, but with how little space there is with the Paxton SC, I'm going to need to get creative with adding a 2nd separator....was hoping I could share the same separator as the valve cover breathers.

[GTS Dean]

Dan - I think you are very correct about the source of the oil. I didn't look closely at the area while my engine was being rebuilt, or I would have immediately seen it:

The timing chain is lubed by a small, drilled orifice in the main oil gallery between the filter/cooler adapter and the #1 cam bearing. The oiled chain engages the cam sprocket and flings off droplets that get sucked straight into a box below the t-stat. The CCV vent is on the box roof at the back corner and pulls oil mist straight out, thru the PCV valve, then into the intake manifold under extended high vacuum deceleration. You can see the path pretty well in photo #1 with the valve disconnected from the tee.

Installing a simple cover plate across the front and stuffing a bit of stainless scouring pad mesh loosely in the void would capture almost all the oil and let it drain down behind the sprocket to the pan. But, without pulling the timing cover, sprocket and cam retainer, it's easier to treat the condition externally using a properly plumbed CCV catch can than it is to effect a cure inside the engine.