PVC Catch can system.... Final conclusive answer
08-16-2007, 11:34 AM
#142
TECH Fanatic
iTrader: (9)
Join Date: Apr 2005
Location: ATL/Savannah Georgia
Posts: 1,395
Likes: 0
Received 0 Likes
on
0 Posts
This is what I'm running now (as of last night):
-During Cruising the intake draws vacuum on rear ports.
-During Boost the turbo draws vacuum from the intake side (tapped the filter pipe of the STS)
-Check valve #1 prevents the intake from pulling vacuum out of the catch can.
-Check valve #2 prevents boost from entering crankcase
-Front port on pass valve cover is venting to atmosphere through a 3" filter at all times
Issues: I think there needs to be another catch can before the line running to the intake because the PCV is the only thing catching oil before it reaches the intake manifold during vacuum.
If I could rework this, I would run a 3/8" line off each rear port going to their own catch cans. Then the outlet port of each catch can would "T" togethor and run into the intake for vac. The pass front port would still vent to atmosphere. During cruising the #1 check valve would stay shut as the intake is pulling vacuum and that would prevent oil from getting into intake of turbo. Then under boost the turbo would pull vacuum, the #2 check valve would shut and the oil would still be caught by the catch cans before running down the lines going to the turbo because they are installed in-line right off the valve covers.
Heres a pic of how it is now:
-During Cruising the intake draws vacuum on rear ports.
-During Boost the turbo draws vacuum from the intake side (tapped the filter pipe of the STS)
-Check valve #1 prevents the intake from pulling vacuum out of the catch can.
-Check valve #2 prevents boost from entering crankcase
-Front port on pass valve cover is venting to atmosphere through a 3" filter at all times
Issues: I think there needs to be another catch can before the line running to the intake because the PCV is the only thing catching oil before it reaches the intake manifold during vacuum.
If I could rework this, I would run a 3/8" line off each rear port going to their own catch cans. Then the outlet port of each catch can would "T" togethor and run into the intake for vac. The pass front port would still vent to atmosphere. During cruising the #1 check valve would stay shut as the intake is pulling vacuum and that would prevent oil from getting into intake of turbo. Then under boost the turbo would pull vacuum, the #2 check valve would shut and the oil would still be caught by the catch cans before running down the lines going to the turbo because they are installed in-line right off the valve covers.
Heres a pic of how it is now:
Last edited by JAvenger007; 08-16-2007 at 11:40 AM.
08-16-2007, 04:08 PM
#143
Staging Lane
Join Date: Apr 2007
Location: Melbourne, Australia
Posts: 57
Likes: 0
Received 0 Likes
on
0 Posts
The car doesn't consume any oil at all .
It's only a slight whistle and only on idle ,Under load or even when I put my finger over it it goes away .
I'm going to fit a small filter on it and see what happens .
It's only a slight whistle and only on idle ,Under load or even when I put my finger over it it goes away .
I'm going to fit a small filter on it and see what happens .
Originally Posted by mondi2002
I would use a long tube & run it to the ground around the K member.
You should not have a whiste. Are you blowing allot of oil out of it?
I would pop the oil cap when its running, rev it a little and see if it is blowing allot. If so you have other problems.
You should not have a whiste. Are you blowing allot of oil out of it?
I would pop the oil cap when its running, rev it a little and see if it is blowing allot. If so you have other problems.
08-16-2007, 06:02 PM
#144
Originally Posted by 2002ws-6
You need to let some atnosphere in the crankcase. The factory used filtered air off the line that is on the side of the throttle body. This is the line that is always plugged in FI, otherwise it would pressurise the crankcase while boosting.
08-16-2007, 08:20 PM
#145
TECH Apprentice
iTrader: (5)
Join Date: Oct 2003
Location: Glendale,AZ
Posts: 382
Likes: 0
Received 0 Likes
on
0 Posts
Try this, pull vacuum on your crankcase with no way to let air in. When your engine pulls a seal or gasket inside or sucks your Rear Main Seal in, that should provide the answer you where looking for. And even if that line at the throttle body is pulling a small vacuum from the venturi effect, the large vacuum of the pcv system will pull harder.
08-16-2007, 08:25 PM
#146
TECH Apprentice
iTrader: (5)
Join Date: Oct 2003
Location: Glendale,AZ
Posts: 382
Likes: 0
Received 0 Likes
on
0 Posts
Javenger I think now that you put the second check valve there on the line to the turbo inlet, you've got the right set up. When the PCV stops pulling vacuum the turbo inlet starts pulling for you.
08-16-2007, 09:10 PM
#147
Originally Posted by 2002ws-6
Try this, pull vacuum on your crankcase with no way to let air in. When your engine pulls a seal or gasket inside or sucks your Rear Main Seal in, that should provide the answer you where looking for. And even if that line at the throttle body is pulling a small vacuum from the venturi effect, the large vacuum of the pcv system will pull harder.
I appreciate the education...that's why I've been following this thread.
08-16-2007, 10:23 PM
#149
TECH Fanatic
iTrader: (9)
Join Date: Apr 2005
Location: ATL/Savannah Georgia
Posts: 1,395
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by 2002ws-6
Javenger I think now that you put the second check valve there on the line to the turbo inlet, you've got the right set up. When the PCV stops pulling vacuum the turbo inlet starts pulling for you.
08-17-2007, 07:10 AM
#151
Thanks for the add'l info...makes sense. So NOT having an original PCV valve in there is NOT a good thing. Mine is long since gone, having been tossed when I first adapted the STS setup for my GTO. Now with the GenTT twins, I need a better approach than the STS used (which had no valve, just a solenoid to prevent boost from flowing into the crankcase). The factory valve is obviously going to be important as well as the check valves. I hadn't realized the issue of pulling too much in at high vacuum times (I am picturing a downshift through a turn w/ HUGE vacuum, then stomping it open on exit...lots of crud will have been drawn in).
Is there a decent (and cheap
) "universal" pcv valve that will work with with the McMaster check valves?
Again, thanks for helping me to better grasp this. Lots to think about.
Is there a decent (and cheap
) "universal" pcv valve that will work with with the McMaster check valves? Again, thanks for helping me to better grasp this. Lots to think about.
08-17-2007, 07:12 AM
#152
Originally Posted by MIGHTYMOUSE
just by browsing the above pictures; don' tdo it that way
if the catch can is not between the engine and the intake, then it cannot catch anything before it goes into the intake (oil)
if the catch can is not between the engine and the intake, then it cannot catch anything before it goes into the intake (oil)
08-17-2007, 08:35 AM
#153
10 Second Club
iTrader: (7)
Join Date: May 2004
Location: Detroit
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by MIGHTYMOUSE
just by browsing the above pictures; don' tdo it that way
if the catch can is not between the engine and the intake, then it cannot catch anything before it goes into the intake (oil)
if the catch can is not between the engine and the intake, then it cannot catch anything before it goes into the intake (oil)
Yeah, it's just a vacuum canister!!
08-17-2007, 09:05 AM
#154
TECH Apprentice
iTrader: (5)
Join Date: Oct 2003
Location: Glendale,AZ
Posts: 382
Likes: 0
Received 0 Likes
on
0 Posts
I see there is a difference, in trying to keep oil out of the intake, and keeping the stock pcv system working. I have never had any issue pulling too much oil into the intake. What I did was make my stock PCV system work while not under boost and the vent to atmosphere while boosting. If you are having a oil into the intake problem then an actual oil seperator somewhere in the line to the intake manifld would make sence. It seems that there are 2 seperate ideas going on in the same thread.
08-17-2007, 11:04 AM
#155
I cannot speak for an LS1, but the LS2 clearly needs a catchcan as part of the PCV system. With the previous setup, I caught a lot of oil in the 'Husky' separator that I used. I have decided to upgrade to a better catchcan now.
In the drawing above, simply insert the catchcan between the two "T"s and all should be well. That way, the oil is separated from the air whether going into the intake or the turbo inlet...or to the outside air, if that's the case.
In the drawing above, simply insert the catchcan between the two "T"s and all should be well. That way, the oil is separated from the air whether going into the intake or the turbo inlet...or to the outside air, if that's the case.
08-17-2007, 01:57 PM
#156
TECH Fanatic
iTrader: (9)
Join Date: Apr 2005
Location: ATL/Savannah Georgia
Posts: 1,395
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by MTBDOC
I cannot speak for an LS1, but the LS2 clearly needs a catchcan as part of the PCV system. With the previous setup, I caught a lot of oil in the 'Husky' separator that I used. I have decided to upgrade to a better catchcan now.
In the drawing above, simply insert the catchcan between the two "T"s and all should be well. That way, the oil is separated from the air whether going into the intake or the turbo inlet...or to the outside air, if that's the case.
In the drawing above, simply insert the catchcan between the two "T"s and all should be well. That way, the oil is separated from the air whether going into the intake or the turbo inlet...or to the outside air, if that's the case.
11-07-2007, 09:27 PM
#159
I'm gonna stick to the breathers, and call it done. Don't get any oil smell and not much residue. Eventually, maybe... next build at least it'll be front mount and I won't have to run a line to all the way to the back to the inlet side of the turbo.
