BlindSpot

Hey Guys:

I am getting close to the install of my A&A kit on my otherwise stock 09 LS3. I am confident now in my tune, and the mechanical installation is straightforward. As soon as I get through one more Scottsdale Cars Coffee tomorrow, I will start the mechanical install.

I have a small change I want to make in the design of the A&A FI kit and I want to bounce it by any experts who want to add or change my mind, in case I've missed something, but I don't think I have. It is small and only impacts the crankcase vent design.

As I am laying out the build I think A&A has some creative design built into their kit. One design, in particular, I really like, they create a crankcase vent through the Oil fill cap which is the highest location in the crankcase. A&A claims that this replaces a need for a catch can. I hate catch cans. They look ugly and remind me of the mechanical version of adult diapers. So I will use the A&A components and vent via the oil filler cap where it is far less likely that solids will make it that high. This vent travels from the oil fill cap directly to the new air filter located in front of the blower.

Now for the change - In addition to this vent A&A keeps the factory crankcase (PCV) which is nothing more than a simple small U shaped hose connecting a much lower crankcase vent then directly into the intake manifold. A&A supplies a check valve to insert into the factory U shaped vent. I understand the check valve BC under boost, if the manifold is pressurized, then you might end up pressurizing the crankcase (not really, but trying to). So the valve prevents that. However, I don't think I need this vent at all, as long as I have the oil fill cap vent installed.

So, unless I've missed something, instead of installing the check valve, I want to install a dowel pin and completely close off the factory vent, then Install the blocked PCV back in place so all CC venting will travel via the oil cap vent.

Another reason for this change, I am concerned, over time, the check valve will become contaminated with CC solids and it will no longer function, but be held in the open position which will reduce boost in the intake manifold.

So, any FB?

Thanks!

realcanuk

Do some reading on proper crankcase ventilation and pcv systems. You might reconsider.

schpenxel

I agree.

You want blowby to get sucked out as soon as possible and intake vacuum does a good job of that.

BlindSpot

OK thanks - Thought with the very modest boost I was after, that wouldn't be a significant factor. Now I might want to reconsider the catch can as I am concerned as dirty as this port is, the check valve might not last too long.

neverstop

agreed with these guys. also, after personally going through multiple different catch can and pcv systems I have to say just contact mighty mouse and get his vaccum pcv setup and follow the instructions and call it done. it's the best setup by far and I wayyyyy over thought this and wasted time/money as a result.

90zcrex

If you were to block the crankcase vent like you propose, you wouldn't have much/any vacuum assisted crankcase ventilation at cruise and part throttle as your only vacuum source would be the intake tube. Like the others said you need to look into a catch can setup if you want to keep everything clean while still maintaining proper crankcase evacuation.

BlindSpot

Yeah, I'm pretty convinced I am back to the catch can which I'd rather avoid. What I'd do is mount A&As check valve on the "Clean", return side of the catch can (also the vacuum IM side). That way the check valve should last w/o need or concern.

The only other option - I sourced a similar (maybe identical) check valve as A&A uses. I'd buy half dozen, then I'd get into a regular maintenance routine and just change out the check valve maybe every oil change.

I was hoping that such a modest boost (6/8lbs, no other mods) it wouldn't have much impact. But, the reason I came here, Don't want to create a new, unnecessary issue.

Only one other possible "theory" that maybe BC the A&A design has the additional Oil fill cap vent, that solid vapors tend to be minimized down at the PCV. That might reduce the catch can need.

Unreal

Order a mm can unless you want to replace rear mains on a regular basis. The amount of venting needed on a boosted ls is crazy.

GeneSch

You will have issues. I blew mine out and then went with the MM. Save yourself the time and trouble. Its cheap for what you get.

Unreal

If you really don't like the looks of one, mount it in the fender or some place you can't see it.

BlindSpot

That's an idea. I'll figure something out. I am back onto a catch can then. Just wrapped up SD Cars Coffee, and actually starting my install today. Will have the install done and there for the next CC.

schpenxel

Either do it the way A&A says to do it or do a full blown PCV Mighty Mouse catch can IMO. You really do need something sucking blow by out, makes a huge difference on engine life

BlindSpot

Got it...Will do! I am concentrating on the install now, so will start with the AA recommendation, then do the CC a little down the road after I get the tune in and ironed out.

schpenxel

Sounds like a plan

Mike's LS3

A&A design is fine. At WOT, the clean side routing from the oil cap to the air cleaner allows the blower to scavenge out the blow by from the engine. On the dirty side, the one way check valve prevents boost pressures from entering the intake valley.
I had a catch can prior to the S/C install. I asked Andy if I needed a C.C. at the time A&A did the install and Andy said "No". No issues with blow by or oil consumption at 9-10 psi. with an A&A kit.

schpenxel

A&A setup should work fine for most, that's how mine is setup now too

David@MMS

thanks for the support guys! I have a few new options as well.