Plumbing Back Atmo Bov's

[ZRBE]

Sorry in advance if this has been covered but the post I did find had already been deleted..

I have a HKS SSQ and the sound is dreadful and illegal.. It sits on the cooler pipe just after my intercooler (Drivers side) obviously trying to hide it from Mr. Policeman.

Question is, am I able to plumb the HKS BOV back?

I don't think I can..

I also have a brand new Kompact Turbosmart BOV & an RB20det BOV w/ stock crossover pipe.

But I can't just put the Kompact one on because I cannot close my bonnet.

So should I remove my cooler pipe going into the plenum? And put the original crossover pipe with the stock BOV.

Or find somewhere to put this Kompact one in?

Because it needs to be close to the MAF, right?

Cheers guys.

[GTSBoy]

The BOV should be physically located close to the throttle body and should return just before the turbo (after the AFM, and pointing towards the turbo and away from the AFM). So the stock location is the best location for achieving the first part of that, but realistically it can be located anywhere on the post turbo piping if you are desperate to find a spot for it.

The logic for placing it close to the TB is that the air only ever has to move towards the engine. If you locate it well away from the TB, then when the BOV vents, the air between the BOV and the TB has to reverse direction before it can flow out the BOV, which causes some people some concern (and I can understand why).

cheers

[ZRBE]

Okay, that cleared a bit up for me. Cheers.

The only way I can fit the Kompact one is if I sit it on the pipe sideways?

But I'm sure that would be fine..

[SargeRX8]

Yes the SSQV can be plumbed back. The front cover is removeable and people fit an outlet into it which permits plumb back. Although where its mounted at the moment is very far from where you want to plumb back to, I would suggest throwing a stock piece back in there. I run a stock piece with 20psi, no worries.

[ZRBE]

Yes the SSQV can be plumbed back. The front cover is removeable and people fit an outlet into it which permits plumb back. Although where its mounted at the moment is very far from where you want to plumb back to, I would suggest throwing a stock piece back in there. I run a stock piece with 20psi, no worries.

Yeah, think I might just go back to stock and hopefully won't need any different cooler pipes.

The stock RB20 BOV is very easy to press in compared to the Kompact one I have..

Might just be the spring dying from old age I guess.

Thanks guys, pretty much cleared this up for me.

Delete if need be, mods.

[Ben C34]

Maybe it doesn't really achieve anything, but I bash to top of the stock bovs in with a hammer and a socket a little bit to add preload to the spring. Haven't had any issues with leaks and it doesn't cost anything, and in the stock location noone can see you took to it with a hammer!

[scotty nm35]

Haha, I have seen that done with fuel regs also. It works I guess, and I do like free mods.

[KiwiRS4T]

I have seen bovs either side of the I/c and even some (oem) on the intercooler. I am planning to relocate mine to the turbo side so that there is just a short pipe for the return to the turbo inlet. The job of the bov is to relieve the pressure on the turbo and most of the air being expelled will come from the turbo after the throttle is shut. The air between the bov and the throttle does not all have to be expelled.

And yes there is a stock part for the HKS bov to accommodate a return pipe... in fact there is a number of alternative pipe sizes...e.g. http://www.ebay.com/itm/HKS-Blow-Off-Valve-BOV-SSQV-outlet-1-Recirculation-Adapter-/320965078546?pt=Motors_Car_Truck_Parts_Accessories&hash=item4abb026e12&vxp=mtr

The BOV should be physically located close to the throttle body and should return just before the turbo (after the AFM, and pointing towards the turbo and away from the AFM). So the stock location is the best location for achieving the first part of that, but realistically it can be located anywhere on the post turbo piping if you are desperate to find a spot for it.

The logic for placing it close to the TB is that the air only ever has to move towards the engine. If you locate it well away from the TB, then when the BOV vents, the air between the BOV and the TB has to reverse direction before it can flow out the BOV, which causes some people some concern (and I can understand why).

cheers

[ZRBE]

Haha, knowing my luck I'll bash it and I'll break it.

Just going to try fit it as close as possible to the intake..

[SargeRX8]

You dont need to bash it. When on boost theres 12 or what ever boodt you're running coming through the silicone hose on your bov pushing down on it to help keep it shut. So as long you've got some spring pressure she'll be fine.

[89CAL]

Mine is plumbed from just after the turbo, Its probably not ideal but I havent had any problems

[GTSBoy]

The air between the bov and the throttle does not all have to be expelled.tr

You cannot relieve the pressure just to one side of the BOV without relieving the pressure throughout the whole IC pipe length. If the BOV is a long way from the TB, then air that was previously flowing towards the TB does in fact have to turn around and flow the other way in order to decrease the pressure in the tract. You cannot decrease the pressure without letting the air out. To argue otherwise is simply wrong.

There is a reason that Nissan and other OEMs put them where they do. Why do you think Nissan would go to the effort of that stupid plastic return pipe arrangement under the front of the engine bay on GTRs when they could have just put the BOVs on the hot pipe? It may not be the single most important reason to do anything involved with BOVs, but it is a valid reason.

[scotty nm35]

Correct, you will probably feel an engine surge as the pressure and flow reverberate back to the bov if it is placed on the hot side.

[Ben C34]

You dont need to bash it. When on boost theres 12 or what ever boodt you're running coming through the silicone hose on your bov pushing down on it to help keep it shut. So as long you've got some spring pressure she'll be fine.

Tell that to the guys that have had bovs leaking

[SargeRX8]

Tell that to the guys that have had bovs leaking

Different story of their valve is damaged or not sealing. On a properly functioning valve in good working order it should hold the pressure just fine.

[ZRBE]

Mine is plumbed from just after the turbo, Its probably not ideal but I havent had any problems

That pic helped. That is your AFM with red & yellow plug? Yes.

Also my wastegate (external) has NO pipe at all, just the wastegate blowing straight onto my turbo oil line.. I don't like that

Is it as easy as making up a pipe and bending it back into the exhaust?

[GTSBoy]

Yes it is that easy.....except that you have to be able to bolt it all together once it is welded up. So a little thought during the "design" phase can save you a lot of swearing later. Main point of interest are the bolts/nuts holding the dump flange to the turbine housing outlet.

[shaunus]

Just take the plastic piece out from the vent on the SSQV. Will be much quieter and not make that high pitched whistle. I also couldn't stand the SSQV sound. This worked. Try it.

[hardsteppa]

"air that was previously flowing towards the TB does in fact have to turn around and flow the other way in order to decrease the pressure in the tract."

I put it forward, there's no need for the air to reverse and flow the other way. Consider this - throttle shuts, airflow into engine stops as throttle plate has now blocked path. Compressor still spinning and pumping air into piping which is now not flowing. BOV located straight after compressor on intercooler piping lets this air out rather than pressure building and pushing against compressor. So the airflow would be effectively stopped, pressure remains the same, and any incoming air would continue to flow the same way, just be diverted straight out the BOV rather than continuing through towards the engine. Get back on throttle and more boost pressure is already there as it hadn't been depressurised in front of throttle plate.

To be honest i think the difference between putting it just before throttle, or just after compressor, would be sweet F.A, in most cases, but it makes sense to me to put it in front of compressor. For another reason, when no longer being driven by the turbine (under closed throttle) the compressor will slow down alot more trying to drive air through the intercooler rather than allowing it to vent out straight away before passing through the I/C.

Obviously this is based on zero hours of research and development by me and I'm sure auto manufacturers might have given it at least a few hours testing.....

[ZRBE]

Who's got some pics of their BOV's and where they are plumbed back?

Would be easier in my case to fit it just after the compressor, because when I shut my boot there is hardly ANY room...

Probably cause its been whacked in the front end.

This chassis damage affects a lot, I am slowly learning

Edited September 12, 2013 by ZRBE