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Old 05-20-2010, 01:31 AM   #1
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Default BOV recirc or not recirc differences?

So I currently have my BOV recirculating. If I choose to eliminate the recirc line and put a filter right off the BOV, is there a benefit? Or does it do a better benefit to keep it recirculating? Whatever answers are given will require explanations of whys or why nots.
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Old 05-20-2010, 01:53 AM   #2
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Since you have a standalone Ms, I am assuming you're using an IAT and not the stock maf. Therefore, it doesn't matter if you recirculate or not. Recirculation is required when using a maf because the air is already metered.
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Old 05-20-2010, 01:56 AM   #3
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Screw recirc if you run a MAP based system. Its usually needed on a MAF/AFM system so that the amount of airflow read by the meter is the amount actually going into the engine. Hence why non-recirced DSMs that use a 1G or 2G MAF in the stock location tend to run like crap on shifts. They see that air flow, fuel accordingly, and run rich for a moment on the shift.

But with a MAP based system, you dont have to deal with that. And why send already heated air back through the turbo for a second go-round?

The only thing that I can see being an advantage is quiet. But I will just find a way to muffle it anyway.
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Old 05-20-2010, 02:03 AM   #4
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I remember when I ran my stock ecu I needed it, but I just don't see the point anymore unless there is some kind of benefit to the compressor, which I don't see. So it's comin off unless there's a reason I should keep it. As for noise, it's pretty noisy when it blows off now, but it doesn't sound smooth like a vent to atmosphere bov would sound.
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Old 05-20-2010, 02:19 AM   #5
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VTA for the mad tyte whooshy soundz yo.
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Old 05-20-2010, 10:14 AM   #6
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Your just blowing hot ait into your intake, get rid of it.
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Old 05-20-2010, 10:53 AM   #7
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I have the same situation. I am thinking of removing mine also. I ordered it with the recirculating valve from BEGI, but that was when I wanted it to be stealthy quiet. Now its a track car, so who cares. It is quite, but why put the hot air back into the system and there are about 6 or 8 clamps, a couple of pipes, and about 3 or 4 couplers I could do without if I go with the bov. I like the idea of removing all of those possible leak/failue points from the system. Its a bummer when your shat starts leaking at the track and you lose track time to come in and tighten it all up.
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Old 05-20-2010, 11:04 AM   #8
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If your intercooler is worth a damn it's not blowing 'hot' air back into your intake .

I ran VTA for about a week before I loathed the sound. On went the Forge bypass.

-Zach
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Old 05-20-2010, 11:38 AM   #9
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usually for some reason emissions **** doesnt like VTA either.
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Old 05-20-2010, 06:02 PM   #10
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Quote:
Originally Posted by thasac View Post
If your intercooler is worth a damn it's not blowing 'hot' air back into your intake .

I ran VTA for about a week before I loathed the sound. On went the Forge bypass.

-Zach
I've yet seen an IC that was 100% efficiant
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Old 05-20-2010, 08:59 PM   #11
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Quote:
Originally Posted by miataspeed2005 View Post
I've yet seen an IC that was 100% efficiant
That's not my point. 90% of the intake locations people are running on this forum draw air from under the hood which means it's already WAY above ambient temp.

Plus

Whether you recirculate or not your still heating the intake air substantially due to the fact that your routing it through a smoking hot turbo housing. At the end of the day, any temp increase caused by a bypass valve is negligible compared to the temp increase caused by the turbo itself.

IMO

-Zach
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Old 05-21-2010, 01:16 AM   #12
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If you have a MAF and the BOV is after it, you should\need to recruiclate it. But you can have a MAF setup and have a bov thats before and in that case you won't need to recirculate. If you are running MAP I wouldn't recirculate.
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Old 05-23-2010, 12:27 AM   #13
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i think if your in it for true performance that by pass is the way to go,(prove me wrong other wise) i dont think there is a benefit to VTA, that air charge was already cooled so if i goes through the bypass its going to be cooled again, i think by passing the pressure to the inlet will help that turbo spool up faster and less energy will be needed to bring it up to boost.
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Old 05-23-2010, 05:08 AM   #14
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Quote:
Originally Posted by shlammed View Post
usually for some reason emissions **** doesnt like VTA either.
The cam breather is plumbed into the intake so that the oil vapor gets burned by the engine, rather than vented to atmosphere. Putting in a VTA blowoff valve defeats that, which is the big emissions reason why OEMs don't do it.

VTA can be made to work with a MAF system, because most of the time when the manifold goes from boost to vacuum you're closing the throttle all the way. 0% throttle means the injectors get shut down, which makes the airflow measurement irrelevant. The real problem is that many of them leak at idle (less expensive ones especially), which doesn't matter with recirculation, but is obviously a lot more of a problem with VTA.

--Ian
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Old 05-23-2010, 01:19 PM   #15
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Quote:
Originally Posted by miataspeed2005 View Post
I've yet seen an IC that was 100% efficiant
mine is.
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Old 05-25-2010, 01:46 PM   #16
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So I finally swapped my VTA filter on the BOV and eliminated the recirc setup. As far as running better, I didn't notice anything different. It's actually quieter than the recirc setup, and it sounds a hell of a lot smoother when it blows off. Plus the fact that theres a little less bullshit under my hood give me some satisfaction.
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