Intake vacuum port. Mixture
#1
New Member
Thread Starter
Intake vacuum port. Mixture
Hi guys! This is my first post, but I'm reading this forum few years already, so I'm not nube, and know pretty a lot about Z's.
I have a 350Z GT 2006 non/revup with a lot of bolt-on's.
Both my valve covers breathing to atmosphere. Intake vacuum port is not in use.
Here is the thing: I guess ECU assuming that some amount of air(vapor) have to get in the intake via intake vacuum port and making mixture with this extra volume in mind. I put the hose on the vacuum port with a small breather. As for me, car runs much better when intake vacuum port not capped. From another side, if ECU don't paying attention on that port, I prefer to cap it to have a perfect mixture.
Please, only facts.
And yes, I kill a lot of time looking for this answer, but nobody know that yet
P.S.: Sorry for my English.
I have a 350Z GT 2006 non/revup with a lot of bolt-on's.
Both my valve covers breathing to atmosphere. Intake vacuum port is not in use.
Here is the thing: I guess ECU assuming that some amount of air(vapor) have to get in the intake via intake vacuum port and making mixture with this extra volume in mind. I put the hose on the vacuum port with a small breather. As for me, car runs much better when intake vacuum port not capped. From another side, if ECU don't paying attention on that port, I prefer to cap it to have a perfect mixture.
Please, only facts.
And yes, I kill a lot of time looking for this answer, but nobody know that yet
P.S.: Sorry for my English.
Last edited by OdesiTT; 09-19-2016 at 02:21 PM.
#3
New Member
Thread Starter
I got a Oil catch can, so don't worry, I'm not making too much pollution.
But still a question: are you sure that "car thinks" that there have to be extra inlet?
Here is my intake and vacuum port with a hose and breather
Last edited by OdesiTT; 06-07-2015 at 06:09 AM.
#5
New Member
Thread Starter
But what is wrong with air instead of oil vapor? Any proof that ECU not assume that this port bringing some air? I understanding, its behind of the MAF, but I think, Nissan engineers adjust ECU to count it even if it's not metered. Am I wrong?
#7
New Member
Thread Starter
I guess you are right, because amount of oxygen in oil vapor is minimal. I know it's sounds stupid, but maybe somebody dynoed intake with capped and open port and have some numbers? I would like to see AFR , but I missing my OBD2 scanner. If somebody have it, and can check AFR with capped and uncapped port, it's will resolve very old mystery and will be very helpful for community.
Trending Topics
#9
Registered User
I guess you are right, because amount of oxygen in oil vapor is minimal. I know it's sounds stupid, but maybe somebody dynoed intake with capped and open port and have some numbers? I would like to see AFR , but I missing my OBD2 scanner. If somebody have it, and can check AFR with capped and uncapped port, it's will resolve very old mystery and will be very helpful for community.
Ditch that breather setup. The OE valve covers are not meant to be vented due to the orifices ID's. If you absolutely have to vent to atmosphere, cut the crankcase balance tube in the middle and have all 4 ports venting.
#11
New Member
Thread Starter
Lol. I know there is a push clip, just once I was too lazy to adjust the strut bar before replacing the bolts and I shaved thread a little bit and don't want to destroy it completely by trying to screw it down as is. So I'll put it back as soon as I get the same bolt. Also I got a sway bar on the bottom, so I'm OK, no worries)
#12
New Member
Thread Starter
In this case, filter even bigger vacuum leak, if we will follow your logic.
How to create vacuum in something that have a 3" diameter hole?
And again: how would you call a bypass valve in any CAI?
How to create vacuum in something that have a 3" diameter hole?
And again: how would you call a bypass valve in any CAI?
Last edited by OdesiTT; 06-16-2015 at 03:13 PM.
#15
Registered User
iTrader: (1)
You absolutely have to close the intake vacuum port for reasons listed above (unmetered air, fuel trims getting fcked up).
You can leave your valve covers vented open though since that will just push crankcase pressure out of the motor. However, it's a better idea to have a catch can hooked up to the valve covers.
Pretty simple, really.
You can leave your valve covers vented open though since that will just push crankcase pressure out of the motor. However, it's a better idea to have a catch can hooked up to the valve covers.
Pretty simple, really.
#16
New Member
Thread Starter
#17
Please help
Please help
I almost have same issue which is the rpm shaking or stumbling at low rpms with very slow acceleration after warming up, that is what is doing in the video
i went to a lot of garage and they never figured out the problem and changed a lot of things with no fix $$$$$
finally after almost now one year I found experience mechanic ,
he unplugged the passenger side breathing pcv hose from the catch can (( small black box that attached to the passenger side air intake )) and the problem gone !!
How the car is working properly when he unplugging the hose ( with leak ) and having the problem when it’s plugged properly
we didn’t drive the car with high revs when the hose was unplugged but the low rpm stumbling absolutely gone
the mechanic comment is that I have leak somewhere else, so when we plug the hose the built vacuum pressure causing the issue from that other spot leakage
any idea pleaaaseee
where is the problem any solution or it’s really somewhere leak like what the mechanic said ?
do you think plenum gaskets leak , valve cover gasket??
I almost have same issue which is the rpm shaking or stumbling at low rpms with very slow acceleration after warming up, that is what is doing in the video
i went to a lot of garage and they never figured out the problem and changed a lot of things with no fix $$$$$
finally after almost now one year I found experience mechanic ,
he unplugged the passenger side breathing pcv hose from the catch can (( small black box that attached to the passenger side air intake )) and the problem gone !!
How the car is working properly when he unplugging the hose ( with leak ) and having the problem when it’s plugged properly
we didn’t drive the car with high revs when the hose was unplugged but the low rpm stumbling absolutely gone
the mechanic comment is that I have leak somewhere else, so when we plug the hose the built vacuum pressure causing the issue from that other spot leakage
any idea pleaaaseee
where is the problem any solution or it’s really somewhere leak like what the mechanic said ?
do you think plenum gaskets leak , valve cover gasket??
Thread
Thread Starter
Forum
Replies
Last Post
ars88
Zs & Gs For Sale
18
04-04-2016 07:52 AM