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Discussion Starter · #1 ·
I'll keep this short, I bought some new Lower Intercooler Pipes, they are Buschur, and while installing them I realized that my stock recirculating blow off valve setup would not fit without new pipes for it as well.
Can I just cap off the hole in my intake, run a longer vacuum line from the head to the BOV and have it vent to atmosphere? Or does that require a retune?

Thanks!
 

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Discussion Starter · #2 ·
Clarification, the vacuum line on the stock BOV does NOT lead to the head, it just gets close and goes off somewhere else
 

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Have you tried running it VTA before? Generally for VTA to work well you want a speed density tune vs. MAF tune. While I was working on my X I checked out running VTA without a tune just to see how the car functioned and it chugged at idle and died on me every time. I know others have had different experiences but I wouldn't do it without the correct tune. Our cars seem to do a lot better recirc'd unless you have a specific reason/tune to VTA.
 

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Have you tried running it VTA before? Generally for VTA to work well you want a speed density tune vs. MAF tune. While I was working on my X I checked out running VTA without a tune just to see how the car functioned and it chugged at idle and died on me every time. I know others have had different experiences but I wouldn't do it without the correct tune. Our cars seem to do a lot better recirc'd unless you have a specific reason/tune to VTA.
while ill agree that recirc is better for are cars simply because it requires more fiddling to get vta to work well in all situations

as long as the valve is tuned correctly (valve not the car) it will run fine the evo has a maf and map sensor it reads and both and will use both you can see this while logging maf calcs map calcs and load load will switch between the two calcs

problems arise when the valve stays open at idle any hestation that change the vacuum may close the valve, which now changes the length of the intake.

with the valve open at idle the air has like a foot to travel to get to the tb, when the valve suddenly closes the intake track now has the entire licp ic uicp turbo and air box to travel which creates a lot more vacuum and cause the engine to stumble then the vacuum fluctuates which creates a resonance and bam poor idle.

with proper spring pressure and preload a valve can run fine. did it with my cobb valve, synapse trickyer.


valve should stay close at idle and when you rev the car it should open enough to let the air out but not hang open too long
 

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Usually you would run the recirc hose from the lower icp to bov and plug the recirc port in the intake.. I'm kind of confused on what you mean by vacuum line? If you have the LICP without the diverter valve port then you would want to get an UICP with the DV port.. Something like Perrin and I think Speed Curciut also make the UICP like that as well.
 

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he means that the location of the DV port on the LICP is reloacted relative to stock such that he doesn't have the tubing to route the DV to the intake port. So he's wondering if he can just vta. I assume the vacuum line being referenced is the source line that controls the operation of the valve
 
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