Blitz Dump Valve Sucking Air In On Idle

[stranger12]

Hi,

my blitz base is on the manifold intake as replacement for the original dump valve and the port at the back of it to the vacume.

today i noticed the dump valve is sucking air in as if the blitz is sucking air in from the dump valve port

Also i have no base washer would that matter that much ?

base to inlet manifold.

many thanks

[KiwiRS4T]

What?

[stranger12]

Dump valve is sucking air in on idle

Now i know the dump valve is connected from its base to the inlet manifold which provides the positive pressure feedback

You also have a port/ nozzle or whatever you want to call it at top of the dump valve which is connected to the vacum

I think that port sucks the diaphgram in pulling piston up and letting air out when needed

Now the issue is if you hold your hand or even a tissue paper on the venture of the dump valve it is vacumming and sucking air in

Makes sense?

[Ben C34]

That's what happens. Put a stock one back on or plumb that one back.

[GTSBoy]

I'm guessing you're not a native English speaker. Perhaps you need a photo with some arrows pointing out the features you are talking about.

For one thing.....dump valve is not a normal term. We will assume you're talking about the BOV, which is still not even the right term on a Skyline, because in truth, what it really is is a compressor bypass valve.

Because it is a compressor bypass valve, it is actually intended to be connected back to the compressor inlet. The vast majority of stupidity associated with Skylines revolves around venting BOVs. Leaving them open to the air requires that do you a few other mods, most of which don;t get done by most people who like venting BOVs. Hence the stupidity.

Anyway.....please do what I said in the first paragraph.

[stranger12]

@GTSBoy

Many thanks for the explanation . Yes I am referring to the BOV or in here is it referred to as dump valve .

I have installed the blitz which is a direct replacement for the manufacture bov.

If you look at the pic below.

1. Area highlighted in red is connected to the base of the inlet which is connnected to the inlet manifold pipe . It has no paper washer between the too metals but it doesn't seem to leak .

2.Area highlighted in black is connected to the vacume ( negative pressure) which I think opens the diaphragm and pulls the bov piston up to let the excessive pressure out.

3. the area highlighted in green is where I am getting vacume on, at idle and across rev range until the bov opens and vents the excess of air in which case it then blocks rather than suck air in .

I know with AFM you are not meant to have BOV as it can run rich between gears but I am ok with that rather my issue is why is it sucking air in .

Is the diaphragm gone so the vacume is sucking air in ?

Edited June 8, 2015 by stranger12

[Ben C34]

That's what happens. Stock ones leak also.

Raise the spring pressure if it is adjustable but then it won't work as nice.

[stranger12]

well I did and as you said it only opens on high pressure ( high rpm range).

I want it to come on from 2k .

I did adjust the screw in all the way and still it was sucking air in , maybe it is by design but I guess that messes the air.fuell ratio as you are getting extra air from the inlet port?

I am currently having misfire and trying to find the cause and this being one of it

[Ben C34]

Yep

[Hadouken]

it has to much vacume.

ploom beck in

[stranger12]

So guess what u guys are saying is bov going to leak and it is by design?

[Ben C34]

Yes. Atmosphere venting bovs aren't that good..

With afm ultra fail.

With maf still fail.

Have you never seen guys running small air filters on bovs before?

[Missileman]

My stock recirculation valve leaked when I pressure tested the system, lubed the shaft of the valve with a tiny bit of moly grease and it holds 30 psi now.

[stranger12]

so if you do recirc then it should be ok ? simply connect it to the turbo inlet pipe ?

[Blackkers]

If you look at the pic below.

1. Area highlighted in red is connected to the base of the inlet which is connnected to the inlet manifold pipe . It has no paper washer between the too metals but it doesn't seem to leak .

If you have no gasket for the bov then I can guarantee it will leak boost above 4-5psi. I tested it even after cleaning the surfaces

Stock bovs leak vacuum too but the air that leaks in has been measured by the air flow meter so it doesn't upset anything.

I hate to say it but unless you go mafless on a different ecu then you're 100% better off going back to the stock bov with an oem metal gasket

Edited June 8, 2015 by Blackkers

[Hadouken]

google it