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Old May 7, 2008 | 05:06 PM
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no breather?

How bad is it to run a breather filter instead of routing it to the intake? I only ask because I have a Buschur hardpipe and it doesn't have a nipple on it. The car idles very rich (10:1) when I come to a stop. It rises slowly but always comes back down to rich after the throttle pedal is let off. I haven't had any trouble with other intakes before. I think the breather could be the issue of idling rich. The car also swings lean sometimes while cruising (17:1+)...and sometimes swings really rich. Am I right?

Also, can someone please post up a maf scaling of the Buschur hardpipe intake kit so I can at least be close to the scaling for that intake before I start? I would really appreciate it.

Last edited by RedLanEVO; May 7, 2008 at 05:09 PM.
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Old May 7, 2008 | 06:12 PM
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bump for someone to help me on this subjuect
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Old May 7, 2008 | 06:21 PM
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Running a breather filter instead of back to the intake pipe can mess with your fuel trims. The breather filter is letting in unmetered air to the IM. The fuel trims will have to go more positive to correct the situation.
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Old May 7, 2008 | 06:38 PM
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So it is the intake that is causing this mess. My trims are more whacked than you can imagine. The car won't even want to idle. So how do I compensate for the breather being on the valve cover? I want it so I can drive it at least to my tune tomorrow.
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Old May 7, 2008 | 07:13 PM
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Drill a hole in the intake tube. Tap it, put a nipple in it. And put the line back on.
The whole situation, drill bit, tap, nipple will cost you less than $10 at a hardware store.

*Done*
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Old May 7, 2008 | 09:17 PM
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The Buschur hardpipe causes turbulance, its not because of the unmetered air from the valve cover breather. They even have a big disclaimer on their website where you'd order this hardpipe. The valve cover breather isn't forcing much air (even with excessive ring blow-by...which would cause more issues than anything), its creating a SLIGHT suction and only pulling in the spent exhaust gases in the crankcase. This suction is so small so it won't suck oil in either. Its the boost blow-by (or faulty PCV valve) that forces the excessive unmetered air into the intake, which is NOT a factory designed intention.

Also, when adding an intake tube for the breather, it needs to be at a specific angle and protrusion to create the correct amount of suction. Otherwise it will create too much suction or none at all.
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Old May 8, 2008 | 05:33 AM
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Oh, I bought my Buschur hardpipe used. Well, anyways, so what I need to get done is to get the MAF rescaled for the Buschur hardpipe?

But, doesn't all intake hardpipes cause turbulence? This is the only one I have ever had problems with.
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Old May 8, 2008 | 06:07 AM
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Originally Posted by Jack_of_Trades
The valve cover breather isn't forcing much air (even with excessive ring blow-by...which would cause more issues than anything), its creating a SLIGHT suction and only pulling in the spent exhaust gases in the crankcase. This suction is so small so it won't suck oil in either. Its the boost blow-by (or faulty PCV valve) that forces the excessive unmetered air into the intake, which is NOT a factory designed intention.
I agree with you that the hardpipe screw with the MAF readings, but no breather hose fitted can screw with the trims much more than you think as well.

It matters how much vacuum you are pulling at idle. If you are pulling a good amount of vacuum at idle or cruise, the air enters the breather, through the valve cover, through the PCV valve, into the IM. This air this way is never counted by the MAF. If you have the breather hose connected, it is now first counted by the MAF before it takes it's little journey. That's why the breather hose is there in the first place.

Blow by or a faulty PCV doesn't force unmetered air into the intake. Blow by forces air past the cylinder rings, causing excess pressure in the crankcase, which can cause problems like your dipstick blowing out and a lot of oil being pushed through the breather hose. If the PCV vavle is faulty, under boost, it's not letting unmetered air in...it's the opposite. The boost is allowed to escape under the valve cover.

So, if this guy wants to run with his breather hose unhooked without tapping for a new nipple, he will probably have to compensate with the MAF scaling table. I would say if you are still running a MAF, set it up right and put the nipple back on.


Eric
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Old May 8, 2008 | 06:23 AM
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Originally Posted by l2r99gst
. . . This air this way is never counted by the MAF. If you have the breather hose connected, it is now first counted by the MAF before it takes it's little journey. That's why the breather hose is there in the first place. . . .

Eric
What are you talking about? The hose comes into the intake tube AFTER THE MAF! The MAF has NO WAY of metering any air here.

The poor idle quality is solely due to the aluminum intake pipe. You can either put a little filter on the valve cover vent to prevent any crud from getting in there, or put a nipple on the intake pipe as mentioned above and reconnect the hose. That is what I would recommend. . .

Good luck!
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Old May 8, 2008 | 06:28 AM
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I plugged my breather and delete the PCV valve with a open fitting and dump the blow by gas to the road, no problem what so ever.
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Old May 8, 2008 | 06:52 AM
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Originally Posted by EVOlutionary
What are you talking about? The hose comes into the intake tube AFTER THE MAF! The MAF has NO WAY of metering any air here.

The poor idle quality is solely due to the aluminum intake pipe. You can either put a little filter on the valve cover vent to prevent any crud from getting in there, or put a nipple on the intake pipe as mentioned above and reconnect the hose. That is what I would recommend. . .

Good luck!
I don't know why so many people have a hard time understanding this, then come and argue with me.

The breather hose is connected to the turbo intake pipe after the MAF so that IT WILL BE COUNTED. If you understand how the PCV system works, it's really easy to understand.

For probably the 100th time, let me explain this again.

During idle or cruise conditions where their is vacuum in the intake manifold, the PCV valve is pulled open. The air follows this path:

1. Into the air filter
2. Through the MAF and counted
3. Into the breather hose
4. Under the valve cover
5. Out the valve cover through the PCV valve
6. Into the intake manifold
7. Into the cylinders

If you unhook the breather hose from the intake pipe, you are bypassing steps 1-3 and the air is not counted by the MAF.

Do you understand now?

Last edited by l2r99gst; May 8, 2008 at 06:55 AM.
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Old May 8, 2008 | 06:54 AM
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Originally Posted by fugiwara
I plugged my breather and delete the PCV valve with a open fitting and dump the blow by gas to the road, no problem what so ever.
That's not the best idea in the world. The PCV system not only helps blowby gases to be combined with fresh air to be burned again in the cylinders, but it also helps moisture to escape. If you delete the PCV, then the only time anything can escape is during positive pressure in the crankcase.

When functioning properly, the PCV helps with the vacuum from the intake manifold to clear any blow-by gases or moisture from under the valve cover/crank case.
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Old May 8, 2008 | 08:23 AM
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Alright with all this arguing. This is way off topic. I need to rescale my maf. That is the answer I got already. Now no more arguing.
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Old May 8, 2008 | 08:03 PM
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Originally Posted by l2r99gst
I don't know why so many people have a hard time understanding this, then come and argue with me.

The breather hose is connected to the turbo intake pipe after the MAF so that IT WILL BE COUNTED. If you understand how the PCV system works, it's really easy to understand.

For probably the 100th time, let me explain this again.

During idle or cruise conditions where their is vacuum in the intake manifold, the PCV valve is pulled open. The air follows this path:

1. Into the air filter
2. Through the MAF and counted
3. Into the breather hose
4. Under the valve cover
5. Out the valve cover through the PCV valve
6. Into the intake manifold
7. Into the cylinders

If you unhook the breather hose from the intake pipe, you are bypassing steps 1-3 and the air is not counted by the MAF.

Do you understand now?
No, you are wrong again.

The air comes OUT of the vent on the front right of the valve cover and goes INTO the turbo intake pipe after the MAF. It is very simple to see this - take off the rubber hose and put your finger up to the nipple sticking out the valve cover. You can feal the pulses of air blowing out.

Research:
https://www.evolutionm.net/forums/sh...d.php?t=200793

Under manifold vacuum the PCV valve is open and the crankcase is vented. Under boost the PCV valve closes, but the suction created in the turbo intake pipe takes over to vent the crankcase.
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Old May 8, 2008 | 08:19 PM
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Right.

Under vacuum, air is sucked out of the crankcase from the PCV valve into the intake manifold and and the unburned exhaust gases are redistributed into the combustion chamber, all while drawing fresh air into the crankcase from the filtered air intake track since the vacuum in the intake manifold is far greater than the vacuum in the air intake piping.

Under boost, the PCV closes and any pressurized blow-by exhaust gases in the crankcase escape into the air intake piping which is aided by the large vacuum created by the high volume of air entering the turbo.
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