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I just recently added the Bob's oil catch can on my 2006 GT that also includes the Saleen VI S/C with 3.6 pulley at between 7.0-8.0 psi boost at WOT..
So far I've been very pleased with the Bob's can and haven't noticed any oily liquid at the PCV connectors at the intake, but rather just a slight oil film..
My concern however is due to increased crankcase pressure from running a supercharger, if I should also consider running a breather in order to reduce crankcase pressure during WOT..
At any rate, I came across the CFM billet valve cover breather that replaces just the oil filler cap and from my understanding it includes a one way baffled check ball valve which is supposedly fully compatible with the factory PCV system that stays completely closed during normal driving conditions while in vaccum and once you go into boost at WOT, the valve then opens to relieve any unwanted crankcase pressure..
Anyway, I'd really appreciate any feedback from anyone who may be familiar with this breather kit and whatever the pro's and con's may happen to be as well..
Not sure that thing will do anything with a PD type blower. Your PCV system is never going to encounter a situation where it is going to have positive pressure. Your PCV intake should be before the blower blades so it won't pressurize, you will always have flow.
Not sure that thing will do anything with a PD type blower. Your PCV system is never going to encounter a situation where it is going to have positive pressure. Your PCV intake should be before the blower blades so it won't pressurize, you will always have flow.
I'm not quite sure what a PD type blower is, but the Saleen blower I have is the twin screw type similar with the Edelbrock e-force..
From my understanding the PCV vacuum hose runs from the driver's side cam cover and directly into the blowers intake manifold port behind the throttle body so I don't know if it's before the blower blades or not ?
All I do know is I had to install a catch can/oil separator as i was getting excess crankcase vapor oil into the upper intake of the blower through the PCV hose and then dripping out of the throttle body.. I was then recommended by Brenspeed, JDM and 281 motorsports to install an oil separator as they all confirmed that running my type of supercharger does indeed increase crankcase pressure.. So I followed their recommendation and installed my current Bob's catch can..
As for always having vacuum flow through the PCV is concerned ? I don't know if this is accurate or not, but It's also from my understanding that once your car goes into wide open throttle regardless of being naturally aspirated or forced induction, vacuum stops flowing into the upper intake as the valve closes..
Therefore if anything I've mentioned here is accurate ? Then I can certainly understand how running a breather which is actually a pressure relief valve would be beneficial when the car is running at wide open throttle or supposedly whenever going into boost with a blower
Last edited by m05fastbackGT; 10/23/15 at 11:36 AM.
Yes when there is 0 manifold pressure or vacuum the valve will close, but it should open when crankcase pressure builds. It won't open as quickly as that oil cap breather but it will open.
Personally, I just deleted my PCV system and installed breathers on both valve covers (valve removed from cam cover) and the an oil cap breather. Mine doesn't have a check valve, just a baffle. Even with a catch can you're not going to catch everything and I just don't want to run that blow by in my engine.
Yes when there is 0 manifold pressure or vacuum the valve will close, but it should open when crankcase pressure builds. It won't open as quickly as that oil cap breather but it will open.
Personally, I just deleted my PCV system and installed breathers on both valve covers (valve removed from cam cover) and the an oil cap breather. Mine doesn't have a check valve, just a baffle. Even with a catch can you're not going to catch everything and I just don't want to run that blow by in my engine.
I first started out using JLT catch cans for awhile.. Although they did catch some oil there was still crankcase vapor oil passing through the PCV hose connectors and getting into the intake manifold, so then I decided to try running breathers on just the cam covers but kept the stock oil cap intact and I also didn't remove the PCV valve because I was under the impression that it was integrated into the cam cover and was therefore not removable..
I was also looking into replacing the oil cap with a breather along with the cam cover breathers on each side, but JDM had mentioned that running an oil cap breather would lean the air/fuel ratio by allowing un-metered air into the crankcase and would therefore require having my calibration tunes revised which really didn't make sense at all to me, as I don't understand how running a breather through the crankcase has anything to do with affecting air/fuel
Anyhow I ran the breathers for about 6 weeks and didn't notice any problems and my car actually ran better, however as others have posted I was concerned with the breathers eventually becoming saturated and seeping oil throughout the engine bay and was also concerned about having to deal with smelling crankcase odor inside the cabin as well..
I then saw all the positive reviews about the Bob's catch can and decided to give it a shot and I can honestly say that after running the Bob's can after the past 7 weeks, it so far has done it's job and not only does the can catch oil but I've also checked the PCV hose connectors at the intake manifold and I have found no oil, at least at this point.. I've also checked the throttle body several times and there has also been no oil..
I'm also hoping that by adding this CFM billet valve cover breather with it's integrated pressure relief valve will also help keep crankcase oil from getting into the upper intake along with the Bob's catch can.. But I will say this, if in the event they don't help ? I will most definitely go back to running breathers, that you can be sure of..
I do have a question for you.. How were able to remove your PCV valve from your cam cover ? Did you have to remove the cam cover first ?
If you can also provide some pics as to how you removed it, I'd be really very grateful and btw: I really like the pics you submitted of your engine bay..
-Rocky
Last edited by m05fastbackGT; 10/24/15 at 10:05 AM.
I first started out using JLT catch cans for awhile.. Although they did catch some oil there was still crankcase vapor oil passing through the PCV hose connectors and getting into the intake manifold, so then I decided to try running breathers on just the cam covers but kept the stock oil cap intact and I also didn't remove the PCV valve because I was under the impression that it was integrated into the cam cover and was therefore not removable..
I was also looking into replacing the oil cap with a breather along with the cam cover breathers on each side, but JDM had mentioned that running an oil cap breather would lean the air/fuel ratio by allowing un-metered air into the crankcase and would therefore require having my calibration tunes revised which really didn't make sense at all to me, as I don't understand how running a breather through the crankcase has anything to do with affecting air/fuel
Anyhow I ran the breathers for about 6 weeks and didn't notice any problems and my car actually ran better, however as others have posted I was concerned with the breathers eventually becoming saturated and seeping oil throughout the engine bay and was also concerned about having to deal with smelling crankcase odor inside the cabin as well..
I then saw all the positive reviews about the Bob's catch can and decided to give it a shot and I can honestly say that after running the Bob's can after the past 7 weeks, it so far has done it's job and not only does the can catch oil but I've also checked the PCV hose connectors at the intake manifold and I have found no oil, at least at this point.. I've also checked the throttle body several times and there has also been no oil..
I'm also hoping that by adding this CFM billet valve cover breather with it's integrated pressure relief valve will also help keep crankcase oil from getting into the upper intake along with the Bob's catch can.. But I will say this, if in the event they don't help ? I will most definitely go back to running breathers, that you can be sure of..
I do have a question for you.. How were able to remove your PCV valve from your cam cover ? Did you have to remove the cam cover first ?
If you can also provide some pics as to how you removed it, I'd be really very grateful and btw: I really like the pics you submitted of your engine bay..
-Rocky
Air in the crank case is not going to do anything to A/F ratios. I think they were maybe referring to leaving the manifold or intake ports open when installing breathers. I've always run breathers on my builds.
They will get saturated with oil and do have to be changed every once in a while. Now when you had your breathers it probably got saturated pretty quickly because you basically had only one outlet. Putting a breather on the driver's side without removing the actual PCV valve does nothing. The valve will stay closed and nothing will ever come out of it. If you remove the valve and run an oil cap breather there will now be 3 outlets for the crankcase and you will have a lot less build up of oil saturating the filters.
To remove the actual PCV valve you do have to take off the cam cover. Then you cut and pull back on the baffle to expose the little pipe where the valve is. I cut that open with a dremel and removed the little valve and then just folded the baffle back into place. I don't have any pics but it's simple. I have a set of stock covers sitting around in my garage somewhere if you really need some pics on what I'm talking about.
Air in the crank case is not going to do anything to A/F ratios. I think they were maybe referring to leaving the manifold or intake ports open when installing breathers. I've always run breathers on my builds.
They will get saturated with oil and do have to be changed every once in a while. Now when you had your breathers it probably got saturated pretty quickly because you basically had only one outlet. Putting a breather on the driver's side without removing the actual PCV valve does nothing. The valve will stay closed and nothing will ever come out of it. If you remove the valve and run an oil cap breather there will now be 3 outlets for the crankcase and you will have a lot less build up of oil saturating the filters.
To remove the actual PCV valve you do have to take off the cam cover. Then you cut and pull back on the baffle to expose the little pipe where the valve is. I cut that open with a dremel and removed the little valve and then just folded the baffle back into place. I don't have any pics but it's simple. I have a set of stock covers sitting around in my garage somewhere if you really need some pics on what I'm talking about.
I didn't think that Air in the crankcase had anything to do with it either, so perhaps as you said maybe they thought for some reason that I'd end up leaving the intake ports open after installing the breathers which again wouldn't make any logical sense, as you have to cap off the ports otherwise it's going to cause a serious vacuum leak lol.
After reading over your post, I now have a much better understanding for removing the PCV valve.. I just hope that when I was running the breathers without removing the PCV valve first, that it didn't end up causing serious crankcase pressure build up because of the valve staying closed ?
I also don't understand why Brenspeed didn't bring to my attention that it was also required to remove the PCV valve prior to installing the breathers, as they were the vendors who recommended running an open breather set up in the first place
In the meantime, if you wouldn't mind taking some pics of your stock covers that are sitting in your garage, it would definitely be very helpful along with having a much better understanding of where your coming from as well..
10/22/15, 08:33 PM
