TT5.9mag
Two atmospheres are better than one
Get rid of the pcv valve. You’re pressurizing the crankcase with it. Cap the hole in the throttle body and vent the valve cover with a catch can with as big of a hose that will fit (-10 minimum).
Slant 6 timing help- Torqstorm and Sniper EFI
- Thread starter rich_mc
- Start date
-
TT5.9mag
Two atmospheres are better than one
Not good. Keep boost low and timing conservative, and make sure you have enough octane to not detonate at ALL. The biggest problem is you don’t know what the ring gaps are.
Thanks. I did get this catch can "free" as part of the black Friday sale when I bought the supercharger. What would you suggest be on the outlet side of the can?
TT5.9mag
Two atmospheres are better than one
Those look like 3/8 npt ports and if that’s the case I wouldn’t use that catch can. I’ve made the mistake in the past using venting systems that are too small and you end up chasing your tail. You could try it since it was free but I bet you’ll end up replacing it. My recommendation is to look at some of the motion raceworks stuff, Top Loader Billet Oil Catch Can (Dual 10AN Port) 32-100
Their junk is very expensive but you’ll never have to buy it again. I just bought the one I linked above for my recent small block turbo build.
Their junk is very expensive but you’ll never have to buy it again. I just bought the one I linked above for my recent small block turbo build.
TT5.9mag
Two atmospheres are better than one
A large filter.
After as much as I've spent, what's another $200 plus hoses?!?!
So in my case if I were to use the one suggested, I'd:
- Ditch the PCV
- Run a hose from the PCV port on the valve cover to one of the ports on the can
- Plug the other port in the can as I think it's a dual inlet that is vented through the filter on top?
- Leave the other breather in place that I already have on the front of the valve cover.
TT5.9mag
Two atmospheres are better than one
All correct except,
I’d ditch the breather in the front and plug it, or run two hoses (front and back of the valve cover) to your catch can. And you’ll have to plug the ports in the manifold youre currently using for pcv.
99% understood. To confirm, that means that air could go either way through the filter/catch can into or out of the crankcase in order to normalize crankcase pressure to whatever is needed as there would be no check valves or PCV valves anywhere in the system.
TT5.9mag
Two atmospheres are better than one
Correct. It will be at atmospheric until you are in boost. Then you’ll have crankcase pressure. The goal is to let the pressure out as easily as possible and catch any oil mist at the same time.
Charrlie_S
Well-Known Member
I don't totally agree. On a race car that would be OK, but not really on a street car. I don't have experience with a "supercharger", but I do have with turbos on the street. With any street car you need some way of ventilating the crankcase. Is the engine under boost any time it is running? If not the engine needs some ventilation when not on boost.
PS: the PCV valve will not pressurize the crankcase. When the intake goes positive pressure the PCV valve closes.
TT5.9mag
Two atmospheres are better than one
It’s cool if you disagree but all of my suggestions are based on experience (as I know yours are as well) and I know what’s worked for me. One thing you’re missing is that when the pcv closes under boost you’re still getting blow by passed the rings and now it has nowhere (or very limited area) to escape. The springs in PCV valves are hardly the most reliable and valves themselves are rarely a sealed device. The easiest way to make everything happy with boost is vent the valve cover with large hoses to a catch can. It’s as simple as that.
Charrlie_S
Well-Known Member
I understand about the blowby under boost. That is why you also have a "breather" (going to a oil separator is good) then to the air cleaner.
Another way of venting the crankcase is using the one way check valves, connected to the exhaust with hoses.
Free Shipping on Orders Over $109 at Summit Racing
TT5.9mag
Two atmospheres are better than one
All of that stuff can work, and lots of guys have put in all kinds of one way check valves and do dabs and gizmos and whiz bangs to make the pcv system function but it’s all unnecessary (especially so for a vehicle that is smog exempt) when simply venting the valve cover to a catch can works wonderfully.
Charrlie_S
Well-Known Member
It has nothing to do with whether it passes smog test or not. It has everything to do with fresh air ventilation of the crankcase. Even before the days of the PCV systems, they used a "road draft" tube to create a partial vacuum, to have fresh air circulation in the crank case.
TT5.9mag
Two atmospheres are better than one
I’m very familiar. My reference to smog was because the single hardest pcv system I’ve ever put together was a turbocharged EFI big block Chevy with a mass air meter and a fixed orifice pcv AND it had to pass smog. Trust me if you can make that work you have a good understanding of how to make a pcv system work, and I’m telling you with 100% certainty that a good catch can with big hoses to the valve covers is enough for just about any engine to breath.
Dave_J
Well-Known Member
A BIG coalescing oil to air separator is a must if you are feeding the PVC back into the air intake side of a turbo/supercharger. Even more so with an Intercooler. You do not want oil mist inside the vanes or cooler.
On my Subaru Turbo's, I run 1 on each side 10AN line from the valve covers up to a dual inlet catch can as a first step. Then a 10AN to a Coalescing separator. This then has a 10AN that goes to a fitting in the turbo inlet with a "Spoon" inside that as air flow goes past it creates a low pressure draw. They drain back with the turbo's drain
Last edited:
For anyone interested, the loud hiss of air at cruise was a bit excessive. I read somewhere of someone putting a unifoam sock on to quiet it down. Went looking and found Uni-Filter part # UP-6300 and ordered one. Once arrived, I cut a small hole in the top for the BOV hose to pass through and then put it over the BOV. Only tried it on a trip to the store and back, but it does seem to cut down on the cruise hiss quite a bit. Still passes a ton of air, so I don't think it should cause any other issues - I was able to speak with my son while driving with it rather than almost having to shout like the other day, so much better than before. Doesn't look as sexy as the BOV, but I'm sure I could pull it off quickly with just a nutdriver at a show if desired.
Dave_J
Well-Known Member
Could put a hose extension on it and build a metal box to house it with some dampening.
I'd move that Cone Air filter to the front of the radiator so you have a bit colder air intake. The supercharger will add more than enough heat to the charge. Looks COOL as hell but not functional.
I'd move that Cone Air filter to the front of the radiator so you have a bit colder air intake. The supercharger will add more than enough heat to the charge. Looks COOL as hell but not functional.
No room for the filter between the radiator support and the grill unfortunately... it'd be pretty slick to build a cold air intake box around the filter and then change the marker light in the grill to an inlet duct though...
-
Similar threads
