Is it possible to install a recirculating BOV on a V1 system? I've been told, and have read that in some cases they could be better.

1 example of where I was thinkin it would help is with the A/F ratio (If for nothing else). I remember reading not too long ago about someones A/F ratio goin berserk briefly during shifting due to the BOV releasin the air into the atmosphere.

Is it possible to install? Could it be beneficial?

 

yes its the filter you have to modify to recirculate the air. i have one in my sig but recently changed to a hks bov.

 

modify the filter? in what way?

 

i would say what is the purpose of having it recirculate - do an atmospheric - it's easier to do and it sounds cool also - can't beat the whip when shifting

 

i already have an atmospheric.. but I have read in more than one place on more than one forum for multiple cars that a recirculating BOV is better/more efficient. And I've heard them on my buddies civic and another friends WRX. I think they sound better than an atmospheric.

 

think about where your maf is in relationship to the blower and bov.

 

Yes it is better in most cases to recirculate the air. Keeps a flowing cycle of air...

 

umm when you close the throttle the cycle is broken thus vaccum is created and the bov opens up and lets out the air that would surge the compressor.

 

Expanding on what Jsutter said, it has everything to do with the placement of the MAF and BOV.

On the 4th gen stillen s/c setup the BOV is before the MAF, so releasing the air to the atmosphere won't have any adverse effects because the air hasn't been metered yet.

However, in the 5th gen stillen s/c setup, the BOV is after the MAF, so releasing the air will cause a temporary rich condition. This is because the MAF sees "X" amount of air and tells the ECU there is "X" amount of air coming in so it can add the correct amount of fuel. But if this metered air is released to the atmosphere, the extra fuel is still dumped into the engine causing a disturbance in the A/F mixture. Another example of this type of setup is in the Audi A4 1.8T. The stock bypass valve is after the MAF, so people who put on HKS/Blitz/Greddy blow off valves immediately get a CEL for an a/f problem.

The stock Stillen S/C setup came with a Bosch bypass/recirc valve that routed the air back to the uncharged side. The Bosch unit is only good up to around 10 psi or so, so if you're boosting more than that or if you just want the "wooosh" sound, you'll need a stronger/different BOV.

 

Does Bosch bypass valve produce any sound in between shift?

Andrei

 

no it doesnt make any noise. the recirculating bov is better for automatics stillen told me becasue it holds the boost between shifts. i now have a hks blitz and it releases air everytime i release the gas peddle, where as with the recirculating one it held the boost. as far as it making any difference on the road i cant tell i still whip ****, lol.

 

gotcha.. cool thanks fellas

 

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If the throttle were open the bov would be closed You are backwards... Depending upon where the maf is located would effect the recirculation. In the traditional setup a recirc is not needed/manditory (4th gen) On the 5th gen this would be a good thing.

 

Recirculated BOVs have a very slight advantage of putting some pressure before the SC/turbo and helping it spool faster for turbo or flow more a little more air with SC. I would think it would help turbos more than SCs and I am not sure if it is a huge deal for either.

 

For Turbos yeah, but not really for superchargers. It's belt driven. It rotates in relation to engine rpm.