Atmospheric blow-off on FC?

[Brett]

Sounds you are using something that\'s too rigid to try and seal the hole - ideally you want something thats a good fit, but with a rubberised surface - an O ring as well if possible.  Radiator bungs are good for this.

Also - Can I suggest you completely remove the turbo to intercooler pipe and inspect it for cracks and splits - especially where the feed pipes T off from it.  I\'ve had these crack and split in the past and it causes no end of problems.

[jimmydanny]

Well, the fact that is idling perfectly now, only with the valve in place, no clamps. (i have to get rid of the ice on the inside of the windscreen before moving it to my fathers carport)

But I have used those before on another car, no loss of boost or anything, and also the rubber in the hoses/tubes themselves are sealing pretty well. It is like having the head of a piston engine in rubber, no need for a head gasket then.

Thing is also, the valve is of plastic, so it seals. And the lamp starter is the same size as the plastic nipple on the valve. So the issue is elsewhere, if there is any issue.

One question, might this have something to do with the -4 celcius? Or might that be a factor. It shouldnt be, because when the car is idling, the valve is closed, same as plugging both holes, or plugging one and having the valve in the other. But it aint.

[jimmydanny]

Also, brett, it is not for running without, it is for changing it. I did this to test how the car reacted with an open bov, not recirc. But it wont even idle, as you probably know from this thread.

I can\'t go out buying a 300£ bov when the car wont run with it.

[Brett]

Out of interest... Is it now so cold there that the rubbers/diaphragms are not sealing properly?  Just a thought?

[jimmydanny]

Dont think so, ran some test when I got the car into the carport (with lights, yuhu!)

When I ran with the vac lines disconnected from the valve, the car ran (even with open air vacuum, just a bit high idle), when i connected the valve, the car stopped instantly.

So the problem is, the valve\'s vacuum is doing something with the car that makes it die. Anyone opened one of the original recircs before?

Also, anyone got a cheap replica valve for me to buy to test with/run with while waiting for money?

[Brett]

Will it run if you have your thumb over the end of the BOV outlet?

[jimmydanny]

The BOV vac line? So that I make the vacuum air tight? Yes, it does, I did that when I tested with both holes (no bov) blocked.

Again, if anyone got a cheap replica bov to sell me and send fast as hell, please say so here, I got some issued with PMs for some reason

[Brett]

have you tested it with the outlet side of the BOV disconnected, with your thumb over that hole. (The one with the moulded arrow pointing towards it)

[jimmydanny]

Ah now, I havent really. Too cold, and now it is too late. Will make too much noise starting the car now. Might try it @ the petrol station when filling up later tonite.

EDIT: But, it worked when the vac line to the bov was disconnected, and just sucking air in (it wasnt blocked). So if that is what you are looking for, it aint.

Also, when I sucked on the vac line to the bov, I could hear the piston slam down when I released the pressure with my mouth.

[jimmydanny]

Borrowed my father and tried it now. It stops when he takes away his finger, so the valve is leaking straight through.

Anyone opened the original Mazda valve before?

[Brett]

Never opened one up personally, are you going to repair or replace?

:wave

[jimmydanny]

Replace, ultimately. I love the sound of the GReddy Type RS (friend had one on his S14a), but for now I will try to fix it, and then buy a cheap one for 40£ with shipping, just to not have the leak.

Wonder how much hp I lose with the valve letting air though to the turbo side? 1-2 maybe?

[infernal]

I run a BOV in my FC... Really nice. No problems at all, even though i can assume it runs richer while shifting cause of the afterfiring hehe.

As far as your problem is concerned jimmydanny, a BOV must seal 100% apart from the times when it\'s venting to atmosphere of course. However, a recirculation valve oughts to stay completely closed only when boosting, in order not to leak boost from the output to the input of the compressor.
Many recirculation valves stay a little open during vacuum conditions in the throttle body (which automatically means no boost too), but this doesn\'t affect the AFR cause everything happens inside the circuit after the AFM.
Now if you disconnect the recirculation end, all this becomes false, as you create a second input/output that is not metered.

You will be surprized how little air is entering the system while idling... It\'s not hard to leak from somewhere.

Also change the vacuum lines that go from the Intake Manifold to the MAP and the recirculation valve (or BOV) with quality silicone hose now that you\'re at it.

[yiug412]

just some personal experience here.
  If you are using an used open BOV you really need to take it apart and give it a very good clean so it seals and reacts better. and for the one piston design like the Greddy they will leak when the spring is not tuned properly and a dirty internal. happened to my frd\'s greddy on his S14a and ended up tightening it quite a long way.
   after trying the Blitz and the Greddy on my FC, i ended up with the Baileys DV26, dual piston design which i think is a simple yet effective design. close nice and quick on idle or foot back on gas. Soundwise it\'s not as good as the other two but it does its job well. and it\'s way cheaper than the others as well.

Louis

[jimmydanny]

I got myself a 50£ valve from Biltema (like IKEA for cars, cheap), had to use loads of small metal plates to get the spring tightened, but now it works like a charm. But even tho the one I bought was a recirc, it leaked so much on idle that even if I connected it to the intake side, it would struggle with the idle.

But a fat spring and some searching in my friends garage (and some beers later ), we got it working.

That is, until my throttle wire snapped -.- We fixed it with this type of wire connector (like for electrical wire)

Worked well, three of these clamping the throttle wire, as well as some litres of CRC 5-56 down there