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Hi Guys

 

I think I know the answer already, but can someone confirm that this is where the sensor line is supposed to plumb in? The BOV doesn't seem to be opening anough but I think it's because the hose I've used is collapsing under vacuum. It was the only stuff I could see at Halfords that was the right size but didn't consider how it might behave under vacuum

 

IMG_20141108_191926_zpsavoxo35j.jpg

Edited by cammmy

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Personally I don't think I would use that port for the BOV line...

 

That connects to the charcoal canister, so you could be getting fuel vapors on that side, which could speed up deterioration of the BOV (if it uses a rubber membrane) or possibly gum up the BOV if it uses a piston.   But then no where in the intake manifold is truly clean...

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Where is the charcoal canister? I traced the line that I T'd into and it heads towards the back of the car, not the front. Don't know where it ultimately leads to though.

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Under the boot floor, on the right as you look from the back of the car. Kinda almost below the coolant header tank, that area.

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And you really do need a hose that can withstand vacuum, boost, and heat!  A hard plastic line would be best.

 

You could use 4mm PTFE hardline and push-lock pneumatic fittings from Amazon.  The 3D printer guys use it, so should be easy to get.

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Personally I don't think I would use that port for the BOV line...

Which port would you use?

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Good question Sanj!

 

I've read that it's not a great idea to use the MAP sensor line, as in tee into the MAP hose.  As that would add the volume change of the BOV's internal workings, and hysteresis, to the measurement by the MAP sensor.  I'd rather not Tee into the same rail as the MAP, since I would like the ECU to have a clear picture of the level of boost...

 

The BOV that I bought, but haven't installed or tried yet, came with a list of guidelines:

 

 

V. CONNECTING TO A VACUUM SOURCE

a. You will need to locate a vacuum source that is directly connected 
to the intake manifold after the throttle body. It is preferable that the 
Synchronic BOV have its own vacuum source. If you need to tee the 
vacuum source, please insure that the straight section of the tee is in 
direct communication with the Synchronic BOV. See diagram below. 
You will also want to make sure that the vacuum source to the BOV 
is not shared with other pneumatic actuators such as wastegates, 
EGR valves, etc.

 

Looking at the Esprit manual and the description in the EMH manual (EMH.2 page 15).

 

The lower rail is for the MAP sensor, the upper rail is for the charcoal canister, the IAC bypass, the fuel pressure regulator, and the crankcase breather.  That lower rail may not get to the same level of vacuum, due to the IAC feeding air and the crank case breather port, which is why the MAP is on a separate rail.

 

 

IMG_2727.JPG

intake%2520rail.JPG

 

I suppose the place I would use would be the top rail, between cyls 2&3, replacing that brass plug shown in my photo, same as that little plug in the illustration.  However, for people who don't want to modify their car, then the port with the charcoal canister is probably fine, if they don't mind the piston getting stuck and needing a rebuild...

 

Really, we should have a 3rd rail for a BOV ;)

 

Anyone measure the relative vacuum between the 2 rails?

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Hi Travis

 

I've ordered and received some vacuum hose now, so hopefully that will be up to the job. I didn't realise until after that the stuff I used wouldn't be up to the task. It was the only thing I saw at Halfords that was the right size and the thought train stopped there :D

 

As for where to feed it from, for now that port will have to do. I'll put the inline filter back in for the BOV, hopefully that will help.

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Righto, replaced the sensor line with vacuum hose. I'm still not convinced it's good enough though so going to find some proper reinforced stuff.

 

What happens is that the valve seems to work as it should but then seems to shut as the revs drop and I start hearing compressor surge noises again. I would have thought that with the pull type BOV, it should stay open until the pressure equalises?

 

It's either that or the 25mm port on the t piece isn't big enough to release the pressure. Although I'd have thought if that was the case it would surge when the throttle shuts and then smooth out as the pressure dropped?

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Just spoke to HKS UK. They said that normal 4mm silicone vac line is what they recommend and that it's doesn't need to be reinforced. They said that the flutter is likely just the way the valve is working and resonating through the very open intake path I have (I've done the ram air mod so can hear everything that's happening in the intake).

 

Does anyone else have experience with this?

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It's a v4 so there is absolutely no adjustment. Only the V1 had the adjusting screw

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Just been thinking about this. The line that I teed into looks like it has a one way valve in it (I t'd in between this and the head); i'm assuming this is to stop boost going into the charcoal canister but then allow vapour to be drawn into the inlet under vacuum? Could it be that when initially shutting the throttle at high rpm, it's creating instant vacuum that opens the BOV, but then as the one way valve opens and the revs drop, there's no longer enough vacuum to hold the valve open, as air is allowed to enter from the canister?

Would anything bad happen if I temporarily clamped the canister line near the head to test?

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You could have a bad one way valve.  They are cheap to replace. Clamping it might cause a fuel vapor rupture somewhere else, or could cause a problem for the pulse width modulated solenoid at the charcoal canister.

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Okay cheers.

Is the valve there to prevent boost going back to the charcoal canister and then to allow vapour from the canister to the engine under vacuum?

I'm thinking you're correct and it's

not the best line for the SSQV but didn't Dermot have the same BOV and use the same line?

Is there a more suitable port that I can use or can I change amythig. to make this one work better for the BOV?

Edited by cammmy

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Correct, the check valve prevents boost from getting to the charcoal canister.  

 

I think many people use that line, but then many people have problems with the Bailey type piston valves sticking after a while. Probably just a maintenance issue though.

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Is the bailey a push type? I believe the SSQV works almost entirely on vacuum through the signal line and boost actually holds the valve closed. So if the vacuum rapidly drops off, risidual boost will shut the valve again and hold it closed

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Yeah I think the Bailey's that people used were push type.

 

Looks like Dermot had his HKS fitted with an inline filter and connected the the upper rail at the charcoal canister port.

HKS_bov_1.jpg

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So the same one I'm using? The check valve is a small filter which i've also got fitted.

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the filter could be slowing the response of the BOV.  Have you tried removing it?

 

In barometric pressure monitoring devices, they use a steel wool or similar filter to slow and damp the response to rapid pressure changes.  Not sure why Dermot had the filter there, other than to address my original concern about fuel vapor.

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The filter is included with the BOV.

The issue isn't the BOV opening; It seems to do that fine, I just seems to be closing too early. If you build up the boost and rpm then shut the throttle, it blows off but then seems to shut and I get flutter from the intake again.

It's like at higher rpm, there's enough vacuum to open it but it then bleeds away and the valve shuts while there's still boost.

Cheers for all the replies.

I did remove the filter when I had the other hose on there but still the same thing

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That's why I was thinking, start the car and drive it around until the oil is warm and then clamp the canister line and quickly run through a couple of gears. Would effectively make the BOV the only thing on that port and would confirm/rule out that line as the issue

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So rather than clamp the canister line, I started the car and let it warm up/gave it a chance to purge the vapour and then disconnected the line. I put the BOV sensor line directly on the port and gave it a quick drive. I think there's a marked improvement. The BOV seems much more willing to open at lower RPM and there seems to be only a tiny bit of flutter under higher RPM/boost.

 

The only issue is that the ground was wet, so I don't think I was really able to work up to full boost.

 

I revved it at standstill and watched the pistons in the BOV. I only saw the inner piston move but I don't think I was really building up max boost etc, as I was pulling the cable with my fingers rather than flooring it at the pedal and releasing.

 

I need to find somewhere that I can get a mate to stand on it and release while I watch the valves, without pissing off the neighbours.

 

Are there any risks to rerouting the canister line to the back of the car and venting rather than having it connected to the manifold?

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