Jump to content
SAU Community

Blitz Dump Valve Sucking Air In On Idle

stranger12
 Share

Recommended Posts

stranger12 Community Regular

stranger12

Posted
Posted

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

stranger12 Community Regular

stranger12

Posted
  • Author
Posted

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?

GTSBoy Grand Master

GTSBoy

Posted
Posted

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 Community Regular

stranger12

Posted
  • Author
Posted (edited)

@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 ?

296lkjs.jpg

Edited by stranger12
stranger12 Community Regular

stranger12

Posted
  • Author
Posted

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

Blackkers Experienced

Blackkers

Posted
Posted (edited)

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 by Blackkers

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • brillo
      Leak from Tokico BM50 Brake Master Cylinder

      By brillo · Posted

      Hi, SteveL Thank you very much for your reply, you seem to be the only person on the net who has come up with a definitive answer for which I am grateful. The "Leak" was more by way of wet bubbles when the pedal was depressed hard by a buddy while trying to gey a decent pedal when bleeding the system having fitted the rebuilt BM50 back in the car, which now makes perfect sense. A bit of a shame having just rebuilt my BM50, I did not touch the proportioning valve side of things, the BM50 was leaking from the primary piston seal and fluid was running down the the Brake booster hence the need to rebuild, I had never noticed any fluid leaking from that hole previously it only started when I refitted it to the car. The brake lines in the photo are "Kunifer" which is a Copper/Nickel alloy brake pipe, but are only the ones I use to bench bleed Master cylinders, they are perfectly legal to use on vehicles here in the UK, however the lines on the car are PVF coated steel. Thanks again for clearing this up for me, a purchase of a new BMC appears to be on the cards, I have been looking at various options in case my BM50 was not repairable and have looked at the HFM BM57 which I understand is manufactured in Australia.  
    • Gantai
      R33 GTST Steering Rack (49001-19U05) Rebuild?

      By Gantai · Posted

      PXL_20250828_063541093.TS.mp4
    • Gantai
      R33 GTST Steering Rack (49001-19U05) Rebuild?

      By Gantai · Posted

      Well the install is officially done. Filled with fluid and bled it today, but didn't get a chance to take it on a test drive. I'll throw some final pics of the lines and whatnot but you can definitely install a DMAX rack in an R33 with pretty minor mods. I think the only other thing I had to do that isn't documented here is grind a bit of the larger banjo fitting to get it to clear since the banjos are grouped much tighter on the DMAX rack. Also the dust boots from a R33 do not fit either fyi, so if you end up doing this install for whatever reason you'll need to grab those too. One caveat with buying the S15 dust boots however is that the clamps are too small to fit on the R33 inner tie rod since they're much thicker so keep the old clamps around. The boots also twist a bit when adjusting toe but it's not a big deal. No issues or leaks so far, steering feels good and it looks like there's a bit more lock now than I had before. Getting an alignment on Saturday so I'll see how it feels then but seems like it'll be good to go       
    • PranK
      R35 GT-R production ends after 18 years

      By PranK · Posted

    • SteveL
      Leak from Tokico BM50 Brake Master Cylinder

      By SteveL · Posted

      I don't get in here much anymore but I can help you with this.   The hole is a vent (air relief) for the brake proportioning valve, which is built into the master cylinder.    The bad news is that if brake fluid is leaking from that hole then it's getting past the proportioning valve seals.   The really bad news is that no spare parts are available for the proportioning valve either from Nissan or after market.     It's a bit of a PITA getting the proportioning valve out of the master cylinder body anyway but, fortunately, leaks from that area are rare in my experience. BTW, if those are copper (as such) brake lines you should get rid of them.    Bundy (steel) tube is a far better choice (and legal  in Australia - if that's where you are).
×
×
  • Create New...