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Has anyone just put a breather filter on the right side cam cover in place of the full load breather hose or brought any unmetered air into the crankcase? I see cars that breath this way by having vacuum on one valve/cam cover and air in the other but before the Maf sensor. I'm not talking about unmetered air into the throttle body but into the crankcase.
This is what I'm talking about. Option A. Only the filter air in and pcv vacuum out are on opposite covers since I have 2 covers.
Last edited by 60Gunner; Sep 25, 2021 at 08:24 PM.
The PART LOAD breather IS taking air from the FULL LOAD port into the engine crankcase.
The left cam cover ('B'bank) breather goes STRAIGHT to the intake. (and purge valve) The air comes from the right cam cover ('A'bank) via the MAFS and air tube to the throttle.
A FULLY independent crankcase breather system would be required to not set lean codes.
If you disconnect ONE of the hoses, please disconnect BOTH.
If the full load is always air in, then how do I get oil in the air filter tube? I thought it reversed flow under full load when the part load ceased to have much if any vacuum from the intake.
See above diagram.
Right now I have the catch can installed in the part load side with the 2nd vacuum port plugged. I want the full load as air in only. The second vacuum port was going to a pump but the pump I have has too small a inlet so I was going to plan B. Putting a 90° with a hole drilled right above the throttle body OR WHERE the full load hose hooks to the air filter tubing. Follow me? Basically option A.
Last edited by 60Gunner; Sep 25, 2021 at 08:38 PM.
Nevermind. I'll figure it out.
Reading old threads here with so much conflicting information on subjects is useless.
Then there's THREADS LIKE THIS where people like Mikey and timfountain, who obviously have no clue, totally derail useful threads. Haven't seen a catch can on a car since the '70s? Is he for real?
Last edited by 60Gunner; Sep 26, 2021 at 08:43 AM.
At FULL LOAD there is relatively NO vacuum in the intake manifold so if the crankcase needs to EXHALE, it pushes air into the throttle intake plastic tube via the larger hole in the right cam cover.
At PART LOAD, the intake is at relatively high vacuum, so most air is drawn from the left cam cover into the manifold below the throttle.
(hence the terms PART LOAD and FULL LOAD breathers)
At FULL LOAD there is relatively NO vacuum in the intake manifold so if the crankcase needs to EXHALE, it pushes air into the throttle intake plastic tube via the larger hole in the right cam cover.
At PART LOAD, the intake is at relatively high vacuum, so most air is drawn from the left cam cover into the manifold below the throttle.
(hence the terms PART LOAD and FULL LOAD breathers)
Right. I want to eliminate that problem and have vacuum on the part load breather under full load as well. Pushing hot, oily air into the intake tube is just dumb. No offense. But it's a **** poor design. Probably why it went bye bye in later models No?
So short of the vacuum pump, I want to use the vacuum created by the rush of incoming air in the intake tube at the top of the throttle body but not sure how that would work with the full load setup pulling it the other way under part load. Make sense?
Maybe it would still work as intended and not pull air out of the both under full load?
Last edited by 60Gunner; Sep 26, 2021 at 08:59 AM.
This discussion is getting hard to follow with it being in different threads. From what I'm getting so far is that we want to put the catch can in without changing the air flow. That would go back to the original plan (from the thread that I first responded to) where the full and part load breathers would be T'd into the dirty side and the clean sides as shown in the drawing above. Do I have that right? If so, then I'll need to go back and read the stuff about the vacuum pump and where it fits into air flow. And, why? It seems that the vacuum wouldn't change since we really haven't changed the flow; just added in the extra length to suck air. I'm just thinkin here, but I may not want extra vacuum on the SC engine; that might open up the bypass valve too early when I need the boost, like when someone wants to show off or I'm hitting a passing hole on a two-lane highway.
Fitting the catch can without the extra vacuum would be pretty easy for me. I've got the latest Mina Gallery intake setup and that thing comes with a hose and rubber fitting that goes onto the full load breather; the hose being a 10mm. I would need to have the catch can to see exactly where it would fit, but I'm thinking at the forward mount on the right false bulkhead, in front of the FPR in the below pics. The clean side back to the part load port would run under the intake elbow.
So you're saying I can't eliminate the full load hose from the intake tube? Do you see an issue running a hose from the intake tube right at the throttle body to the other vacuum port on the can keeping vacuum on the part load and eliminating the full load altogether? Or would stay air in only if I left It?
Btw, I DO appreciate your input here. There has to be a way to improve on the existing system, maintain at least 10inHg of vacuum, and keep oil and condensation out of the intake from both ends. What about connecting the 2 cam covers with a crossover as well. I have a kit to add ports. A hole saw, grommets, and hose fittings.
Last edited by 60Gunner; Sep 26, 2021 at 12:31 PM.
This discussion is getting hard to follow with it being in different threads. From what I'm getting so far is that we want to put the catch can in without changing the air flow. That would go back to the original plan (from the thread that I first responded to) where the full and part load breathers would be T'd into the dirty side and the clean sides as shown in the drawing above. Do I have that right? If so, then I'll need to go back and read the stuff about the vacuum pump and where it fits into air flow. And, why? It seems that the vacuum wouldn't change since we really haven't changed the flow; just added in the extra length to suck air. I'm just thinkin here, but I may not want extra vacuum on the SC engine; that might open up the bypass valve too early when I need the boost, like when someone wants to show off or I'm hitting a passing hole on a two-lane highway.
Fitting the catch can without the extra vacuum would be pretty easy for me. I've got the latest Mina Gallery intake setup and that thing comes with a hose and rubber fitting that goes onto the full load breather; the hose being a 10mm. I would need to have the catch can to see exactly where it would fit, but I'm thinking at the forward mount on the right false bulkhead, in front of the FPR in the below pics. The clean side back to the part load port would run under the intake elbow.
Actually what I'm trying to do is just keep the full load as air in only and keep the right side venting thru the left side and adding a second vacuum source, be it the pump or a fitting in the intake tube right at the throttle body, to keep vacuum on the part load even under full load essentially making it an all load. The can is set up for this and to draw from the strongest source via the check valves. I'm just afraid the full load will be pulled in 2 different directions at the same time and I'm not quite sure how to keep it as air in and not reversing because of the vacuum I'd be adding right above the throttle body rather than using the pump. I'm afraid the pump would run all the time and burn up rather than shut down at 16inHg because it would never reach that.
How about teeing off the dirty side of the can and running it to the full load cam cover by adding a port in the rear of cover and drilling out the intake tube right above the throttle body rather than using the pump for the second vacuum source on the can. It should then keep the full load breather air in only or like you said run the dirty side there and use that opening in the tube to connect to the 2nd vacuum(clean) port on the can.
Follow all that?
Another option rather than teeing off the dirty side of the can is connect the 2 covers by adding fittings on the back of each and run a hose between them.
Last edited by 60Gunner; Sep 26, 2021 at 02:35 PM.
The reason for this thread was I wanted an answer on the full load breather as I've read different ideas on exactly what it does.
Anyway, I hooked my pump up now and I was wrong. It doesn't run at idle and it won't run until the part load breather drops below 16inHg at which time it will run but the can will use whichever source is highest. It most likely idles somewhere between 18inHg and 22inHg. How much and how quick it drops under load I do not yet know. So good sign for this pump.
However, with that full load breather connected directly to an open air filter, the pump won't get close to 16inHg once it takes over u der full load I wouldn't imagine. So it's hard to say how much vacuum it will provide under full load or exactly when it will take over.
The full load breather is what I'm having trouble understanding; as in, how does it reverse flow? That thing is basically a siphon with a constant airflow sucking into the intake tube. Just like a sandblaster; the air sucks the sand up and shoots it out the tip. The only time that either of these could reverse flow is when you release the valve on the sandblaster (sand falls out of the hose) or shut the engine off for the breather (air goes in until the pressure in the block is equalized). Does that sound right? Also, Bob's (Motorcarman) comments in posts 2 and 6 above seem to fit what I'm thinking of; just run a hose from the right cam cover (part load breather) to the dirty side of the can, tee-in from the right cam cover (full load breather), then run hoses from the two clean sides of the can back to the respective ports on the intake tube and elbow. As we know, this is all part of the emissions crap, which I believe is a closed system. I'm not a fluid dynamics or emissions expert, but I have spent some time rolling around on the garage floor looking at this setup since I haven't set a P1111 code in over a year. I say "closed system" as there are the two valves, purge valve on the firewall and another valve on the right canister with an inlet for air to get in when the purge valve opens and sucks crap from the canisters, which includes fuel tank vapor, back to the intake elbow. Everything gets sucked back into the engine to get burnt up, theoretically anyway.
So, I'm going to continue waiting and reading to see your outcome on this project; I probably wouldn't get into this until next spring, anyway.
It's the full load breather reversing that I had a hard time understanding at first too and it's what I want to not happen. This is when oil is sucked into the intake tube. It happens under load when the part load breather ceases to get enough vacuum from it's hookup at the bottom of the throttle body and the vacuum at the top side of the throttle body caused by the air rushing in with the butterfly wide open, in this case further down the tube at the elbow, is stronger and overcomes the weak vacuum of the part load.
This is why many who use this can drill a hole for a barbed fitting in the tube at the top of throttle body for the second source of vacuum.
I'm looking to better that second source and keep air going in at the full load at all times.
This morning I got the pump wired and it works as intended. I just need to see when it kicks on and at what vacuum. It runs when I turn the key on and continues to run for about 5 seconds after starting the car til vacuum builds in the intake and goes hits 16inHg of vacuum at which point the pump is designed to shut down.
When I pinch off the vacuum line from the low load to the can droppi g the vacuum below 16inHg, the pump kicks on and takes over keeping the dirty side at 16inHg at all times and should new the full load from ever reversing. Right cam cover is air in, left cam cover is air out. Problem solved. No T-ing required.
HOWEVER, T-ing the full load to the dirty side OR adding a fitting at the rear of the right side cam cover to the dirty side may help. Not sure at this point if it would be beneficial or not.
I may be eliminating the full load breather hose from the intake tube altogether or restricting it more by installing a vacuum relief in it if necessary to maintain16inHg vacuum at all times. It's currently like one big vacuum leak.
Maintaining the above stated vacuum is good for a 3 to 6% increase in hp, better ring seal resulting in less blowby, and eliminating pesky oil leaks.
Air in question...
