How is that working with the original MAF? Or should I get a recirc while I\'m at it? This is for now just cosmetic (in terms of sound), as the original.. well isn\'t making a sound? :P
Jim
The blow off valve simply plumbs itself into the intake system, to vent this to atmosphere does not affect the MAF, it will give you a better sound to atmosphere and is what most favour to do with aftermarker valves. As for no sound when its standard then you will probably not hear it if you have standard plumbing and air box, that thing really does its job well. As far as the cosmetic side of things then the valve does not need to be where it is, some say better to be closer to the TB as possible, some put this where there is room and others for show and shine purposes, the sound will be the same no matter where it goes in the engine bay, just keep the vac hose as short as possible.
Pete\'s just said most of what I was thinking :)
Obviously you will need to block the hole left in the inlet when removing the OEM valve. :wave
+2 on what they said ^^
Wouldn\'t it affect the MAF though? Have had this discussion before on an early Evo site as people were putting on VTA BOVs and wondering why the car was stalling when coming off the gas and into neutral.
The MAF will tell the ECU that a certain amount of air is entering the engine, which then calculates an appropriate amount of fuel taking into account throttle position, intake temperature, random bits of witchcraft etc. When you vent to atmosphere for a short time the ECU will be expecting a higher air volume than is actually entering the engine. So it will run very rich for a very short time. Now I don\'t know how sensitive the FC\'s ECU is to that, but I know the Mitsubshi Evo ECU didn\'t like it at all and most people who vented to atmosphere realised the errors of their ways sharpish.
Now on a MAP sensor car, that\'s another matter altogether...
I ran my old T2 stock bar an atmo valve, never had any issues :)
If you think about it the valve works when you are coming off boost, hence the foot is off the throttle and you will be in a leanish state for those few seconds anyway until you plant that foot again. The air entering the airbox from the valve may not be enough to make any difference to the volume of air for those few seconds with the type of MAF installed and maybe the reason why none of us have experiened any problems. A standard ECU does run rich anyway out of the idle area. It would have been interesting though to have mapped that with a wideband at those presise moments and see whether or not the ECU compensates in any way.
Why go for a bov? Might aswell just run nothing. It will give better performance than a bov. And it should sound much better. Never heard a TII tub chatter mind
Tell me, where is the valve? Pics please. I found something that should be it, just behind the air filter, there is a hose going back to something looking like the valve, with a hose going into the intake straight after/before the intercooler again. But when I took the original valve and plugged the air filter side, the car wouldn\'t idle, so I guess that can\'t be it.
Quote from: dthebuk;729131Why go for a bov? Might aswell just run nothing. It will give better performance than a bov. And it should sound much better. Never heard a TII tub chatter mind
If I run without a BOV or recirc I will blast my turbo. Blasting I dunno how many liters of air @ 0.7-1 bar into the turbo trying to reverse it is no good, TII or V12 :)
theres some piping with a valvle in which goes from Turbo - Intercooler piping to the Turbo intake ducting (comes from the air box) Some of the piping has an arrow on it also.
As for the whole BOV argument, I\'ve run turbo car\'s for silly miles with no sort of bov/recirc and they\'ve been absolutely fine. never tried on the fc mind
Try it in longer periods. Might need a new turbo, especially if you run high boost.
Anyways, my car wont idle when the air filter side is plugged (with a screwdriver^^), but when I put the recirc into the air filter side again, it idles perfectly @ 600rpm.
What can cause this? What else does the original recirc do? I mean, it is just a piston in there. Might it be that the vacuum sucks the piston up and makes it stay open or something? Shouldn\'t really matter.
The ONLY difference except having no tubing on the air filter side of the valve, is the angle the valve is staying at. When connected it is horizontal, when I disconnected it, it is vertical. Might this have something to do with it?
Still same issue here folks. When the pre-turbo side is open on the valve (and plugged on the intake ofc. dont want to suck snow into the turbo), there is no idle. It goes to 2k when I start it, and it dies. When I connect the pre-turbo side of the valve to the intake again, it idles. Tried all positions with the valve (ie angle, horiz, vertic and so on).
Also tried by sucking on the vacuum tube from the valve. When I release I hear the spring hit the plastic, so that means the piston is also moving, which means the valve works.
What is this weird thing happening here
Quote from: jimmydanny;729148Try it in longer periods. Might need a new turbo, especially if you run high boost.
This. I was running 1.8bar in my Evo and the one time I tried without the BOV the sound scared the bejeezus out when I actually thought about what was making it.
Okay, still, anyone got an answer for me? This is really bugging me. The valve is a normal recirc, I should be able to plug both holes and the car should still run, but it kinda wont without the valve attached to both sides of the turbo. If I found a picture, I could explain.
Dumb question but you are also blocking the vacuum line going to the BOV, right?
Well, I still have the valve on the manifold side, but not on the air filter side. So I still use the vacuum line on the bov.
Have a look in the technical section in the top of this part of the forum... I did a blow by blow account of BOV removal, along with pics. It\'s possible you have spot one of the smaller hoses coming from the turbo to intercooler pipe... Take a look at the pics and you will see which one I mean. :wave
Same as I did. put it in (original T-piece in plastic, not metal like you got) the T-piece, then plug the air intake side so I don\'t get unmetered air.
The car still dies when I start it, unless I keep it @ 2000 rpm
Sounds like an airleak to me... You need to double and triple check every joint!
:wave
There can\'t be any. The IC side is okay, as it starts when I got the filter side plugged in (on the valve). And also, it must be a pretty nasty leak when it can\'t idle at all?
Can you take some pictures of how it looks?
Yeah sure I thought I should do it. I only got camera flash as light tho, as the car is sitting outside with no proper lighting (flashlight is the only thing I got when working on the car :P )
(http://img528.imageshack.us/img528/9060/leinternet.jpg)
The blue ring is the valve on the IC side. It is connected. The yellow is the vacuum, it is connected.
The red is the air filter/turbo side. It is disconnected, and you can see a screwdriver is used to plug the hole, and it is 100% air tight.
Still, the car wont idle when it is disconnected here.
But when I connect the airfilter/turbo side of the valve again, it starts and idles as it should.
maybe the car is sucking air in through the bov? if the valve is knackered that is.
Well if it is, how can the ECU and AFM accept that? They shouldnt. And if it really does, it is still AFTER the AFM, which means it doesnt matter where it gets the air, it will come, thru the turbo, or thru the valve.
So I think that can\'t be it.
No thinking about it it couldn\'t be. It\'d still be sucking the air from the airbox if it was. It\'s got to be drawing air in from somewhere though or it would idle. Im running a HKS BOV on mine that vents to atmosphere and have had no bother with it at all.
This is, what Einstein would call, impossible. Anyone got an answer to this?
That\'s what I\'m wondering...
If you really must run without the BOV, then remove it completely and block both openings.
You must ensure when sealing the holes, your seal is airtight - it doesn\'t take much of a leak to kill the idle.
I tried with a flurescent lamp starter (perfectly cylindrical) to block the hole as well, clamped it really hard.
So where that leak is coming from, I have no idea.
The fun thing is, I started the car without tightening the clamps on the valve itself, and it started. Thing is, if there was a leak there, it didnt care. When I clamped the lamp start, it didn\'t. So there is something weird going on that shouldnt be possible, obviously.
I can try tomorrow when I got more daylight to film it or something, if I get my mobile phone to start up ever again. Everything is failing here. At the same time -.-
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.
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.
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.
Out of interest... Is it now so cold there that the rubbers/diaphragms are not sealing properly? Just a thought?
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?
Will it run if you have your thumb over the end of the BOV outlet?
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 :)
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)
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.
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?
Never opened one up personally, are you going to repair or replace?
:wave
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?
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.
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
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 :D ), we got it working.
That is, until my throttle wire snapped -.- We fixed it with this type of wire connector (like for electrical wire) (http://shopher.no/images/Sukkerbit_12pk_400x.jpg)
Worked well, three of these clamping the throttle wire, as well as some litres of CRC 5-56 down there :D
Replace that wire man asap. Should this thing snap while driving fast, you can get yourself and your car hurt. :eek: :eek: :eek:
Cant drive fast when there is 1/2 meter of snow :D I only drive sideways now.
But DARN, I drove my friends AE86 with LSD.. Me want asap!
Yep, AE86 is cool! But FC is better!! :Thumbs-up
OFC! But still, I want an LSD on my car asap. Wondered if I could afford a Kaaz when I am also going on a one week skiing trip 800km away.. Doubt it.
Anywho, the valve I got doesn\'t leak, but it stays up for a long time, need to tighten the spring even more (already 0.7cm worth of shims in there).
Might find the money for a proper GReddy or HKS or whatever pretty fast.