Boost check is to the supercharger inlet for vacuum. That pulls from the crank case (the valve cover).Are you using the boost check in the inlet tube line?
(and the PCV in the can on the snout line?
To be fair, the MM website is not intuitive or super helpful. You really have to dig around to figure out what the hell they're selling, beyond the buzz words like BOOST CHECK!!!I’ll need to review their site. I really thought the PCV valve was serving to prevent boost to the can and the Boost Check was for the inlet hose to prevent to going to the inlet…
ETA: as I have contradicted myself in this thread I am obviously not fully grasping the details. I will need to head over to MMS to try to gather up some knowledge.
The boost check AFAIK is a simple check valve. The PCV is (again, AFAIK), a variation on a check valve that allows flow toward the vacuum, but only up to a point and at some differential it closes flow to the vacuum.... and it's something that I need to grasp better (regarding MM's PCV design, specifically.)To be fair, the MM website is not intuitive or super helpful. You really have to dig around to figure out what the hell they're selling, beyond the buzz words like BOOST CHECK!!!
Also, regarding the B15 instructions. Note how the PCV system uses flow restrictions. On purpose.
Just some thoughts from reading this sub-forum:
'Everything' must be metered 007..lolalso remember if u are using vacuum and a fresh air inlet that will be like just opening a hole in the manifold and u will have to account for it going leaner with unmetered air, and if that is too much the TB will be closing and timing lowering to try to keep idle where it should be, that's another reason i rather just use the intake before TB
Good research and excellent info Kitty..The -B15 does not have separate instructions for NA and boosted crankcase ventilation, same set of instructions for both.
-B15 instructions state clean air from intake to passenger valve cover. Driver valve cover and valley to vacuum. Compared to the Cadillac setup, clean air from intake to both valve covers, and valley to vacuum.
Difference between the -B15 and LSA is higher profile baffled valve covers and a baffled valley cover. Not sure if the LSA has a baffle in the valley?
Both stock engines seem restrictive at higher power levels based on the ID of the ports and lines. Guess that's where consideration for increasing fitting and line diameters comes into play? Has anyone given consideration to increasing the vacuum port diameter, what effect it would have?
I'm close to going with the Cadillac setup based on the fact Cadillac was engineered specifically for supercharged application with no consideration for NA, must be some good reason?
Regardless, I have a catch can between the valley and vacuum. In addition, I installed a check valve OUT from the oil fill, thought it would be a good idea just in case too much pressure builds-up at WOT. Still have the stock 3/8" lines and fittings for now though.
I don't have the same level of experience you and others have that contribute regularly. I learn a lot through this forum and try to provide information I feel may be useful. The ventilation subject is on going, and obviously a thoughtful challenge to resolve, at least for me, I'm trying to better understand. It's not a glamorous subject for sure, think it is under rated by many. But if inadequate, rings and seals are at risk, and both require a huge amount of re-work to correct. I have not experienced blown seals to date. I did replace the rear main when I installed the new clutch.Good research and excellent info Kitty..
The first two statements I highlighted above, tell one a lot about what the GM Engineers think about the production of blow-by in an NA Engine, versus an engine with Power Adders, such as a Blower.
Beneath those two statements, I Italicized and underlined other variables related to power adders / potential increase in HP. As HP goes up, so does the increase in pressures playing on the top of the piston. And so 'might' blow-by. These variables are also important to understand..
Today empirically, it seems most have determined that a Number -10 AN line appears to be sufficient to evacuate 1000 HP. But what if your only producing 750 HP. How far down does one need to downsize?
GM placed a 556 HP rating on the stock LSA.
GM includes a 900 HP 'Warranty' for the stock B-15.