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My catch can routing ok?

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Old 02-24-2009, 10:47 AM
  #101  
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Originally Posted by Big Bird WS6
aaron,
i will try this. and let you know. thanks,

but if i have a ls2/ls3 valley cover with the port in it. i dont need to get valve covers with back ports? i can buy ones with out?

thanks
You only need one port off of the valve cover and that's for clean/dirty reversion. A pair of LS6 style valve covers, port on passenger front, is what your looking for.
Old 02-24-2009, 12:04 PM
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thanks. well will any other valve covers have them? ls2?ls3? or just ls6?
Old 02-24-2009, 01:44 PM
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Originally Posted by Big Bird WS6
thanks. well will any other valve covers have them? ls2?ls3? or just ls6?
I think both LS2 and LS3 have only the single port on the passenger front.

Last edited by 405HP_Z06; 02-25-2009 at 12:46 PM.
Old 02-25-2009, 10:22 AM
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thanks
Old 03-02-2009, 08:31 PM
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All of that looks really great, but, how is the "clean side" which connects to the back of the throttle body suppose to "push" clean air into the engine. Even at idle, the motor is pulling vacuum, not pushing air, so even if that line is connected at the back of the throttlebody, how is that pulling clean air? Is it because the air comes from the front of the throttle blade, and the dirty side comes from the valley cover which then has the vacuum, and hence the valve cover pulls the air from the filtered air, through to the crankcase, and then up through the valley cover....I think i see it now, just had to think outloud. Also, it only works when at low vacuum/idle correct? Good deal.
Old 03-02-2009, 08:48 PM
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Oh, and lastly, whats the problem with eliminating the "clean air line" than if you can just throw a breather on the valve cover and draw the clean air from the breather? And Revxtreme obviously has the catch can improperly installed in the pictures on their webpage haha. They have the clean air line running to the catch can from the valve cover, and then from the catch can to the valley cover with a breather on the valve cover. They should fix that.

Lastly, is the RevXtreme catch can anywhere near the same as the Mike Norris piece?

Last edited by Haans249; 03-02-2009 at 09:04 PM.
Old 03-02-2009, 09:28 PM
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Hey Aaron what are your thoughts on instead of using your clean can could you use a pcv in line instead?
Old 03-02-2009, 10:28 PM
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Originally Posted by Haans249
All of that looks really great, but, how is the "clean side" which connects to the back of the throttle body suppose to "push" clean air into the engine. Even at idle, the motor is pulling vacuum, not pushing air, so even if that line is connected at the back of the throttlebody, how is that pulling clean air? Is it because the air comes from the front of the throttle blade, and the dirty side comes from the valley cover which then has the vacuum, and hence the valve cover pulls the air from the filtered air, through to the crankcase, and then up through the valley cover....I think i see it now, just had to think outloud. Also, it only works when at low vacuum/idle correct? Good deal.
Ding, Ding, Ding......

As far as when flow occurs, that depends on if your using a fixed orifice or variable flow valve. Blowby flow is the highest at WOT/high load where PCV system flow is the lowest.

Last edited by 405HP_Z06; 03-03-2009 at 12:55 PM.
Old 03-02-2009, 10:30 PM
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Originally Posted by Haans249
Oh, and lastly, whats the problem with eliminating the "clean air line" than if you can just throw a breather on the valve cover and draw the clean air from the breather? And Revxtreme obviously has the catch can improperly installed in the pictures on their webpage haha. They have the clean air line running to the catch can from the valve cover, and then from the catch can to the valley cover with a breather on the valve cover. They should fix that.

Lastly, is the RevXtreme catch can anywhere near the same as the Mike Norris piece?
If you read the thread, you will have the answer. The RevXtreme is different than the Norris and IMHO, the RevXtreme is a better design.

Last edited by 405HP_Z06; 03-03-2009 at 12:54 PM.
Old 03-02-2009, 10:43 PM
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Originally Posted by boostedgtp
Hey Aaron what are your thoughts on instead of using your clean can could you use a pcv in line instead?
This would be the same as using a one-way check valve. I wouldn't want to put any restrictions in this line. It needs to flow. N/A or FI application?
Old 03-03-2009, 03:36 AM
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So in this pic, why cant the "hose from valve cover port to TB OR bellows port (clean side)" just be a filter?


Is it ONLY because its unmetered air or is there more to it? I read the whole thread but theirs so much info I must have missed it.

Also, can the PCV valve be on the "side of catch can (dirty side)" hose? Maybe just to keep it cleaner?
Old 03-03-2009, 12:48 PM
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Originally Posted by chadnol10
So am I dumb for selling my revxtreme can to get a Mike Norris can? BE HONEST please.
I would keep the RevXtreme, a much better design.

Originally Posted by chadnol10
I just can't stand the rattle of the Revstreme can from the pcv valve inside. Why don't you guys use the external valve so you do'nt get the rattle or is that not going to work as well?
The 'rattle' in the RevXtreme can is a one-way check valve not a PCV valve. Depending on your valley cover/configuration you still need a PCV valve or fixed orifice.

Originally Posted by chadnol10
what is the green dotted line for in the illustrations?
The green dotteed line represents an alternate connection point for throttle bodies that don't have a clean air line connection point. i.e. LS2,3,7

Originally Posted by chadnol10
Is it bad to cap the line going from the TB to the valve cover? I have an LS1 engine, LS6 valley cover, N/A(NO TURBO)
The line from the valve cover to throttle body/air bridge is required for the PCV system to operate properly. This is the clean air feed to the crankcase.
Old 03-03-2009, 12:53 PM
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Originally Posted by David_viny
So in this pic, why cant the "hose from valve cover port to TB OR bellows port (clean side)" just be a filter?
<image snipped>
Is it ONLY because its unmetered air or is there more to it? I read the whole thread but theirs so much info I must have missed it.

Also, can the PCV valve be on the "side of catch can (dirty side)" hose? Maybe just to keep it cleaner?
If you vent the clean air line, you make the closed PCV system an open system. This severly reduces the effectiveness of the system. Go one way or the other, not 50/50. Totally open, ie PCV system delete with breathers or a vacuum pump system, or closed as intended.

If it's a naturally aspirated application, you can put the PCV valve on either side of the catch can.
Old 03-03-2009, 01:11 PM
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Originally Posted by 405HP_Z06
If you vent the clean air line, you make the closed PCV system an open system. This severly reduces the effectiveness of the system. Go one way or the other, not 50/50. Totally open, ie PCV system delete with breathers or a vacuum pump system, or closed as intended.

If it's a naturally aspirated application, you can put the PCV valve on either side of the catch can.
I still don't understand how having the breather is any different than having the "clean air" line from the throttle body to the valve cover. It is still a closed system either way, clean filtered air enters the valve cover, goes down the lifters into the crank case and up out the valley cover into the intake. And in fact, I would bet that adding a breather to the drivers side will only help in the process of flushing clean air through the crankcase. They're doing the same thing, except one the air is going through a tube from a filtered source, and the other the air comes right through the filter. I did read you said something about a large "pressure drop", but if there is a vacuum, then that means there is a restriction, adding the breather and removing the restriction will ONLY allow a greater amount of fresh air to be passed through crank case and thus being much more effective.
Old 03-03-2009, 01:20 PM
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BTW, this is all really GREAT information and great debate, and hopefully educating many people who think the PCV system is a waste!
Old 03-03-2009, 02:23 PM
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Originally Posted by Haans249
I still don't understand how having the breather is any different than having the "clean air" line from the throttle body to the valve cover. It is still a closed system either way, clean filtered air enters the valve cover, goes down the lifters into the crank case and up out the valley cover into the intake. And in fact, I would bet that adding a breather to the drivers side will only help in the process of flushing clean air through the crankcase. They're doing the same thing, except one the air is going through a tube from a filtered source, and the other the air comes right through the filter. I did read you said something about a large "pressure drop", but if there is a vacuum, then that means there is a restriction, adding the breather and removing the restriction will ONLY allow a greater amount of fresh air to be passed through crank case and thus being much more effective.
That's pretty much exactly what I was thinking. And at WOT if the system does temporarily go in reverse, wouldn't it be better for the oil mist to just go into the atmosphere rather then in the intake?
Old 03-03-2009, 10:39 PM
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Originally Posted by Haans249
I still don't understand how having the breather is any different than having the "clean air" line from the throttle body to the valve cover. It is still a closed system either way, clean filtered air enters the valve cover, goes down the lifters into the crank case and up out the valley cover into the intake. And in fact, I would bet that adding a breather to the drivers side will only help in the process of flushing clean air through the crankcase. They're doing the same thing, except one the air is going through a tube from a filtered source, and the other the air comes right through the filter. I did read you said something about a large "pressure drop", but if there is a vacuum, then that means there is a restriction, adding the breather and removing the restriction will ONLY allow a greater amount of fresh air to be passed through crank case and thus being much more effective.
Let's start off with the definitions of an 'open' and 'closed' PCV system:

Open PCV Systems
The open system draws fresh air though a vented oil filler cap. This presents no problem as long as the vapor volume is minimal. However, when the crankcase vapor becomes excessive it is forced back through the vented oil filler cap and into the open atmosphere. The open PCV system, though successful at removing contaminated vapors from the crankcase, is not completely effective as a pollution control device.

Closed PCV Systems
The closed PCV system draws fresh air from the air filter housing. The oil filler cap in this system is NOT vented. Consequently, excess vapor will be carried back to the air filter housing and from there into the intake manifold. The closed system prevents vapor, whether normal or excessive, from reaching the open atmosphere. The closed system is very effective as an air pollution control device. This system uses engine vacuum and the delta-p at the throttle body to evacuate the crankcase.

You CAN use an 'open' PCV system by venting the clean air line; however, it doesn't help the environment nor does it leverage engine pressure differential to better evacuate the crankcase.

Concerning the restriction comment. Unfortunately, that's the nature of a street PFI engine with the intakes we have to use in order to maintain driveability. You will have vacuum, why not use it to your advantage? As far as adding another clean air line to the drivers valve cover, that would be a good idea if your using a non-LS1 valley cover.

Last edited by 405HP_Z06; 03-03-2009 at 11:05 PM.
Old 03-03-2009, 10:41 PM
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Originally Posted by David_viny
That's pretty much exactly what I was thinking. And at WOT if the system does temporarily go in reverse, wouldn't it be better for the oil mist to just go into the atmosphere rather then in the intake?
If you use a correctly designed catch can, routed correctly, carry over oil shouldn't be a problem. This assumes the bottom end doesn't have other mechanical problems that NO catch can or oil separator can help.
Old 03-03-2009, 11:24 PM
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Originally Posted by 405HP_Z06
Let's start off with the definitions of an 'open' and 'closed' PCV system:

Open PCV Systems
The open system draws fresh air though a vented oil filler cap. This presents no problem as long as the vapor volume is minimal. However, when the crankcase vapor becomes excessive it is forced back through the vented oil filler cap and into the open atmosphere. The open PCV system, though successful at removing contaminated vapors from the crankcase, is not completely effective as a pollution control device.

Closed PCV Systems
The closed PCV system draws fresh air from the air filter housing. The oil filler
cap in this system is NOT vented. Consequently, excess vapor will be carried
back to the air filter housing and from there into the intake manifold. The closed system prevents vapor, whether normal or excessive, from reaching the open atmosphere. The closed system is very effective as an air pollution control device. This system uses engine vacuum and the delta-p at the throttle body to evacuate the crankcase.

You CAN use an 'open' PCV system by venting the clean air line; however, it doesn't help the environment nor does it leverage engine pressure differential to better evacuate the crankcase.

Concerning the restriction comment. Unfortunately, that's the nature of a street PFI engine with the intakes we have to use in order to maintain driveability. You will have vacuum, why not use it to your advantage? As far as adding another clean air line to the drivers valve cover, that would be a good idea if your using a non-LS1 valley cover.
The open system still uses the engine vacuum to pull the air out of the crankcase. Also, if you can flush more air through with the filters or larger diameter clean air line and are able to tune for the extra air that should be more beneficial and better. I do see what you're saying about the evacuation of pressure to the air, but in an effort to keep the air entering the intake as clean as possible I believe it would be better to vent to air then send it to the combustion chamber. Although I would bet it wouldn't make any difference.

Even then, I suppose it wouldn't actually make a difference as far as flushing the engine with fresh air because you can only fit so much air through the one port on the valley cover, so I would be willing to bet you wouldn't draw anymore clean air with two breathers, than you would with just the one close clean-air line.

What do you think?
Old 03-04-2009, 12:13 AM
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Originally Posted by Haans249
The open system still uses the engine vacuum to pull the air out of the crankcase.
Yes, but only one side. Your handicapping yourself by venting the clean air side to atmosphere.

Originally Posted by Haans249
Also, if you can flush more air through with the filters or larger diameter clean air line and are able to tune for the extra air that should be more beneficial and better.
Why do you think it would pull MORE air with the clean side vented to atmosphere?


Originally Posted by Haans249
I do see what you're saying about the evacuation of pressure to the air, but in an effort to keep the air entering the intake as clean as possible I believe it would be better to vent to air then send it to the combustion chamber. Although I would bet it wouldn't make any difference.
IF the catch can is designed correctly, routed correctly, and reduces PCV flow velocity to 1 meter/second MINIMUM, carry over oil will NOT be an issue. Yes, it will slightly dilute the intake charge with blow-by gases evacuated from the crankcase, but that's the lesser of two evils. Better to pull it out than leave it in the crankcase.

Originally Posted by Haans249
Even then, I suppose it wouldn't actually make a difference as far as flushing the engine with fresh air because you can only fit so much air through the one port on the valley cover, so I would be willing to bet you wouldn't draw anymore clean air with two breathers, than you would with just the one close clean-air line.

What do you think?
The baseline blow-by design target for engine breathers is 1%. Larger clean air lines and a larger quantity of clean air lines will help in conditions where blow-by exceeds the design target. I think the clean air line and oil cap should NOT be vented to atmosphere.

Last edited by 405HP_Z06; 03-04-2009 at 09:36 PM.


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