pj-c7

Hello,

Wondering if anyone has had any trouble, or has had to do anything, with the PCV valve and/or crank case pressure on boosted Stingrays...

I started reading up on PCV to help me determine if I needed a catch can and the best way to attached it. I also have the heartbeat installed, which relocates the PCV, so it added some complexity.
Couple things I've learned and please correct me if I'm wrong...

I learned that on the Z51 (LT1 Dry Sump), oil reservoiur has an internal baffle for oil/air seperation. So, I figure the clean side has been taken care of by GM.

The confusion, for me anyway, comes from the dirty side. After some research I had determined that, if needed, I would probably attached a catch can on the PCV-to-intake line.

LT1 has baffles built in the valve covers so I figure they should be good but I'm concerned that it may not be enough for the boosted applications?

This is where my confusion comes in...If the PCV valve is going to be closed under boost, since there would be more pressure in the intake than in the crank at the time,
then the only other way that the crank is going to get ventelated would be through the valve cover vent, right?

If that's true then it may make sense to catch can the driver valve cover vent to the intake as well.

I'm actually more concerned about the pressure build up than the catch can stuff. Is the crank case getting evacuated enough on these boosted Stingrays?


Thanks,
Pj

robert miller

Both dry & wet with a blower on the car has blown out front & rear seals. Look at MMS that makes& sales this cans best read his write up on this. Robert

FYREANT

You should look into a breather tank rather than a catch can. Something that will vent enough air quickly. I have an LMR breather and have zero issues with crankcase pressure.

David@MMS

My GEN 4 can flows up to 1500hp based on the line set, and it is happy on many 1000+ hp stingrays.

Almost every V8 (including gen5 gm LT1 and LT4) does not have isolated breathing bank to bank (it all comes from the crank at the bottom of the V, not the heads) This is why one large vent on one valve cover can be perfectly fine vs. 'symmetrical' hoses. Same reason GM does not do this from the factory.

I have basically an off the shelf MMS C7 Wild system on my personal Z and it is one of the fastest C7's on record.



If you are tired of the drawbacks from a full time open venting system, or restricted by a can made only for the stock system, then my stuff is your Solution

pj-c7

Thanks guys.

I looked at the LMR solution but I don't think it will fit since the Heartbeat's intercooler reservoir is taking up the space. I'll have to double check.

I sent an email to MMS via their web site about the wild solution.

My driver valve cover vent actually routes to the air box and not the intake so I wonder if that's relieving crank pressure since it's before the TB and not where the boost pressure is at?

pj-c7

my "novice" thoughts and observations so far, FWIW...


I believe in my application (2016 Z51, M7, with Heartbeat @6PSI) appears that there isn't much concern for crank case pressure or oil buildup in the intake.


I just installed a ported TB and had a chance to inspect it. The air tube (before the TB) was completely dry so, not much coming from the valve cover vent. at least not enough to drop oil in it. I'm guessing the valve cover baffles are helping with this. I have 8000 miles with the heartbeat and 2 track days (HPDE). Car has 16000 miles.


I did notice a slight film of oil in the TB and in the intake section that I could reach with my hand. My guess is most of this is acumulating from the PCV valve air but I guess it's possible that the vent also contributes.


I then ran a boost guauge on the PCV valley cover port (before the PCV valve) and it never showed any pressure during boosting. Note
that during idle the vacuum was not measurable by my standard boost gauge. I did verify there was vacuum by pulling the hose and
caping it with my finger; there was vacuum. I believe you need to measure this particular vacuum in inches of H2O instead of
mercury.


The heartbeat kit relocates the PCV valve into a seperate vacuum block so it was easy for me to tap into the valley port.
I also verified that there is no valve from the valley tube; air flows in both directions before the PCV valve.

I also sent an email to Magnuson tech support asking them if they had any concerns of crank case presures with the heartbeat on my
car. The reply was; "We haven’t heard of any high crank pressures with our supercharger".

So, I'm thinking some kind of catch can on the PCV line and maybe on the driver side vent at some point. I may put one in both to
see which acumulates the most.


With my application (6PSI boost), I'm hoping I can avoid having a breather (which is not legal in MASS) or having to reconfigure the PCV system too much.
Because of my lack of knowledge and experience, I'm not comfortable changing the system. That's just me.

Hope this is somewhat helpful. Welcome any comments/corrections.
Thanks,
Pj

MikeinAZ

Hi,
I have your same set up and in fact, in another topic here we were just discussing this whole thing. So you are right, there is no place w/ the Heartbeat coolant reservoir to put a catch can in that area. I had an Elite catch can prior to my s/c install and it was located right there. So let me stop there and say, I collected a LOT of oil in that catch can, I also have a Z51 drysump system and only fill it w/ 9qts of oil. Don't kid yourself that you don't still get a lot of excess oil vapor going through.

Back to the scenario. I was told by my installer/tuner to put a Mighty Mouse can on and they were the best. I hated to part w/ my Elite as it had done the job I thought it was supposed to but it would no longer fit. In fact the MM can mounts to your radiator shroud under the hood scoop so I ordered one and installed it. It vents out to the atmosphere which I did not understand the significance of at first. After doing a lot of research it made sense, the higher boost and hp levels create a lot more pressure and the venting of the can (breather) vents that pressure out which my Elite can was not doing. So a blessing in disguise that I switched cans and the Elite would not fit. I ordered a can from David at Mighty Mouse that does not have the breather on top but is sealed w/ a hose coming out of it. I ran the hose down under my radiator so it vents down there, no oil smell under the hood and no breather showing.

Now I have the hose from the left valve cover going to one side of the catch can and the hose from the supercharger snout going to the other side of the can. I have capped off the valley port valve and the connection on the intake tube, bypassing those points. I think this can solves both issues you mention. Again after I saw how much oil I was collecting in my can I was so glad I had installed it 3 yrs ago and now am glad I have one that vents out as well. After seeing videos online of guys testing sealed cans vs no sealed I realize the difference and David is a great resource to get a can from. Good luck!

MikeinAZ

Here is the can tucked away under the hood scoop attached to the radiator shroud by a bracket you can get from MMS when you order the can. The hose on top is the vent or breather hose running to under the car, the left hose goes to the s/c snout and the right one to the valve cover.

David@MMS

nice job with the install! i added your pics to the customer gallery