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Old 04-23-2011, 08:17 PM   #61
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Quote:
Originally Posted by MartinezA92 View Post
As soon as that plate closes, is pressure not instantly spiking throughout the whole intake?
Sadly no. The pressure ends up being higher at the TB and the wave hits back towards the turbo. The higher CFM is more of aerodynamic flow. You ever seen a velocity map of an intake manifold? Perfect example right there.

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Old 04-24-2011, 12:12 PM   #62
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They react different. Finally found the website with the cutaways.
http://www.evilution.co.uk/249

All the stock (such as bosch) recirculating ones are like the first one (either rubber diahram or a piston)

The 2nd one is the one with the 2nd piston and thats made to prevent crap from going back into your intake even when the main valve is open. Thats how most regular VTA are.
I think only forge is like that, I haven't seen anything similar in other brands. I'll admit, it operates a bit differently than I thought. It looks like a pop off valve that has a blow off valve stacked on top. I'm willing to bet the spring between the two pistons is just strong enough to hold the valve closed upside down making it a check valve. I can accomplish the same thing by throwing a washer between the valve and valveseat and make sure to keep the valve upright

That said, it doesn't work any differently than what you're calling a recirc bov. At any pressure above atmospheric the pistons are locked together.

Last edited by Asx; 04-24-2011 at 12:36 PM.
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Old 04-24-2011, 12:49 PM   #63
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I'm willing to bet the spring between the two pistons is just strong enough to hold the valve closed upside down making it a check valve.
The spring is actually quite tight. I ended up replacing it with soft spring otherwise i was getting a lot of surges when i let off the gas at anything less than 3-4 psi. If you search the web, that spring is the main reason all the people are complaining about and Forge isnt doing **** about it since they only offer the main valve spring in their bling bling kit.
Its different when in vac and thats what i've been saying all along.

$1.19 from ace hardware is my solution.
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Old 04-24-2011, 02:59 PM   #64
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Quote:
Originally Posted by triple88a View Post
Sadly no. The pressure ends up being higher at the TB and the wave hits back towards the turbo. The higher CFM is more of aerodynamic flow. You ever seen a velocity map of an intake manifold? Perfect example right there.
Grah. I'll just run a rubber hose along the piping then if I decide to recirculate. I dont see a reason to run that crossover tube right in front of everything.
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Old 04-24-2011, 04:31 PM   #65
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Honestly if you're planning on getting rid of ur maf, run a VTA and make it simple for your self.
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Old 04-24-2011, 04:35 PM   #66
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Stealth is the name of the game
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Old 04-24-2011, 04:43 PM   #67
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According to Begi their stock bosch valve makes a "silent sigh".

http://www.bellengineering.net/produ...roducts_id=126
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Old 06-25-2011, 02:19 PM   #68
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Anyone have any experience with the Synapse BOVs? They seem quiet and they seem to have good response.
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Old 06-25-2011, 04:34 PM   #69
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The synapse i've seen is loud. I'm pretty sure they have different models though.

Today i modified my forge and enlarged the holes. Now every small hole is connected to the big hole next to it. Still havent driven it so dont know what it sounds like but i'll post some pics and results when i drive the car later on.
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Old 06-25-2011, 05:11 PM   #70
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Hmm, well we'll see. I'm too impatient - I went ahead and ordered one. Apparently the new model (SB002) is available on their website only, so I snagged it from there. Black finish to match my TB.

I'll be running it with the 1.25" recirc fitting and a little filter, if I can find a decent filter that is. Having a bitch of a time finding a 1.25" ID filter.
EDIT - Nevermind: http://www.knfilters.com/search/prod...x?Prod=62-1512

Last edited by kotomile; 06-25-2011 at 05:27 PM.
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Old 06-25-2011, 07:28 PM   #71
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Thanks for the link, I was looking for the same thing in 1" ID.

Ended up getting a bypass valve from 034 motorsports. A little more expensive than the plastic bosch valve, and I read pretty good reviews from Euro guys who use it.
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Old 06-25-2011, 08:02 PM   #72
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I have a "Go fast bits" BoV from my FM2 kit, thing's very quiet.
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Old 06-25-2011, 08:18 PM   #73
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Run a lawnmower muffler on the output of a VTA BOV
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Old 06-29-2011, 07:25 PM   #74
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Alrighty well my forge bov now sounds like a longer semi truck psssss
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Old 06-29-2011, 07:53 PM   #75
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(zack morris's phone)

Lars's tial is quiet. Y8s greddy type R is silent.
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Old 11-20-2012, 02:53 PM   #76
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Quote:
Originally Posted by MartinezA92 View Post
Thanks for the link, I was looking for the same thing in 1" ID.

Ended up getting a bypass valve from 034 motorsports. A little more expensive than the plastic bosch valve, and I read pretty good reviews from Euro guys who use it.
I figured I'd bump this up and find out how the 034 valve worked out for MartinezA92, or if it was changed for some other solution. I'm thinking we have the same requirements for the same reasons.
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Old 11-20-2012, 05:05 PM   #77
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I ended up using the 034 BPV...and its vented to atm. I stuck a tiny filter on it and wrapped a couple socks around it and it was KIND of quiet. But for some odd reason this BPV sounds so cool when its vented that I took the socks off and stopped caring.

A+ would buy again for any application. No idea how quiet it would be when it's recirc'd
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Old 11-20-2012, 06:30 PM   #78
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Quote:
Originally Posted by kotomile View Post
Anyone have any experience with the Synapse BOVs? They seem quiet and they seem to have good response.
I had a Synapse wastegate on my 944 and thought it was an excellent product. I dont know much about their BOV offerings but I'm sure it will perform as good or better then most on the market.

here you can find a couple vids.

New Synapse BOV Blow-Off Design Eliminates Compressor Surge - Video Dailymotion
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Old 11-20-2012, 06:43 PM   #79
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obviously vent to atmosphere will be louder than doing a bypass valve setup, which they also sell, or perhaps it is just an adapter to convert their bov
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Old 11-20-2012, 09:18 PM   #80
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They seem to have a myriad of adapters for their Diverter Valve (DV001x) or their Synchronic BOV (SB001x) to adapt them to recirculate. They even have a video on their youtube channel:



but dammed if I can tell the difference.

I've currently got a Bosch 710N in hand, but by all reports they are pretty budget and can't take a lot of abuse. The rebuild-able 034 Spec BPV is a direct replacement for my 710N, as is the FrozenBoost "SS Style BOV". They are probably both the same unit, but who knows.

Remember, I'm not looking for more flow or more boost, I'm looking for more quiet...er
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