blow off valve

l4gacy · Post by **l4gacy** » Sat Apr 16, 2005 7:44 pm

What are the benefits of upgrading the blow off valve ??

Can someone suggest a good blowoff valve for a 1993 legacy sedan??

J-MoNeY · Post by **J-MoNeY** » Sat Apr 16, 2005 11:57 pm

Don't do it. There are NO benefits to a BOV. Your stock Diverter Valve will work just fine.

-K- · Post by **-K-** » Sun Apr 17, 2005 3:25 am

The sound.
If running a good bit above stock boost it might need to be replaced.

scottzg · Post by **scottzg** » Sun Apr 17, 2005 4:10 am

J-MoNeY wrote:Don't do it. There are NO benefits to a BOV. Your stock Diverter Valve will work just fine.

YES!

Atmo dumpers create lag and are unkind to the turbo.

azn2nr · Post by **azn2nr** » Sun Apr 17, 2005 4:54 am

if you plan on modding big time than there will be a time and a place for it. youll figure it out when you get there dont worry.

-K- · Post by **-K-** » Sun Apr 17, 2005 9:04 am

Unkind to the turbo?

As for the "lag" atmo venting BOV's are used in racing so if there was any big difference they wouldn't use them.

The stock one is fine and unless you want the sound you don't need to "upgrade" to an aftermarket one.

magicmike · Post by **magicmike** » Sun Apr 17, 2005 5:34 pm

what is the boost limit on the factory valve? I'm running 14psi now. How do I know if its keeping up with the boost?

-K- · Post by **-K-** » Sun Apr 17, 2005 5:41 pm

You can kinda hear/feel if it leaks. You should feel some surge as you roll into the throtle hard.

magicmike · Post by **magicmike** » Sun Apr 17, 2005 6:27 pm

humm, if I stand on the brakes with it in drive and step on the gas a little I can hear what sounds like air escaping. but I have checked all my hoses and dont have any leaks. do you think its the stock valve recirking the air or is there something else wrong in there somewhere?

azn2nr · Post by **azn2nr** » Sun Apr 17, 2005 7:51 pm

its not psi you need to be woried about the valve being able to vent. its volume of air. if your running tmic it should work for a long time but if your running fmic it doesnt have the size needed to let the volume out

scottzg · Post by **scottzg** » Sun Apr 17, 2005 8:14 pm

-K- wrote:Unkind to the turbo?

As for the "lag" atmo venting BOV's are used in racing so if there was any big difference they wouldn't use them.

The recirc keeps the pressure differential on either side of the turbo more equal. The larger differential stalls out the turbo- more wear and lag from slowing and restarting more.

It's also allowing metered air to escape.

Project_Legacy · Post by **Project_Legacy** » Tue Apr 19, 2005 4:08 am

ok. i have a WRX intercooler that i will be using on my ej22t swap. it didnt have a stock BOV at all so its just a big hole there. i did want to get the sound... but after hearing you guys say its bad for the turbo, i dunno what to go with now. what would be good options for recirculating BOV's?

vrg3 · Post by **vrg3** » Tue Apr 19, 2005 4:51 am

You can use our stock one if you make a little adapter.

http://bbs.legacycentral.org/viewtopic.php?t=18585

l4gacy · Post by **l4gacy** » Tue Apr 19, 2005 6:32 am

Ya, I was just wondering. Because theres this talon that drives by my place almost everyday and I can hear it when he drives by, and was wondering if it did anything besides allowing you to hear it better.

dzx · Post by **dzx** » Tue Apr 19, 2005 6:46 am

I really doubt that an atmospheric bov would make a noticeable difference in the turbo during the life of the car. It'd have to be pretty extreme. I've never had any problems with mine other than a little richness right after a quick shift. But that'll be fixed soon.

J-MoNeY · Post by **J-MoNeY** » Tue Apr 19, 2005 7:45 am

l4gacy wrote:Ya, I was just wondering. Because theres this talon that drives by my place almost everyday and I can hear it when he drives by, and was wondering if it did anything besides allowing you to hear it better.

Pffst. My BOV knocks old people on their asses when I go past and shift.

TDGKORN · Post by **TDGKORN** » Tue Apr 19, 2005 2:56 pm

forge motorsports makes really nice bov's. both atmo and recir.

http://www.forgemotorsport.com/content. ... talog=0006

91White-T · Post by **91White-T** » Tue Apr 19, 2005 5:07 pm

Project_Legacy wrote: i did want to get the sound... but after hearing you guys say its bad for the turbo, i dunno what to go with now. what would be good options for recirculating BOV's?

Who said its bad for the turbo? It CAN be bad for idling if it stays open under vacuum, like the stock diverter, but any aftermarket one should be ok, just rich for a second when you shift,

-K- · Post by **-K-** » Tue Apr 19, 2005 5:27 pm

It's not bad, not in any real world way.
The stock BOV with the way the intake is run won't keep shit spooled. There is no way that that amount ao air going the wrong way in the resonator box is keeping the turbo going when you shift.

As for BOV's I like my GFB Stealth FX
http://www.gofastbits.com.au/index.php? ... stealth_fx

Imprezive · Post by **Imprezive** » Wed Oct 26, 2005 8:33 pm

scottzg wrote:
-K- wrote:Unkind to the turbo?

As for the "lag" atmo venting BOV's are used in racing so if there was any big difference they wouldn't use them.
The recirc keeps the pressure differential on either side of the turbo more equal. The larger differential stalls out the turbo- more wear and lag from slowing and restarting more.

It's also allowing metered air to escape.

You've got to be kidding. That is sucha miniscule amount of wear its not even worth thinking about. The worst thing that can come from an atmo is that it doesn't spooled as much as a recirculationone would. And it might get the cops to notice you.

gt2.5turbo · Post by **gt2.5turbo** » Wed Oct 26, 2005 9:02 pm

i bought a slightly used forge recirculating one off of a VW/audi board for 60 shipped to replace my stock one when i did my tmic install and it works great and is noticably louder

irishsetter · Post by **irishsetter** » Thu Oct 27, 2005 12:00 am

I have alway heard that a atom bov is good for spool time and if your worried about wearing down a ten year old turbo then you might want to think about changing your turbo setup.

91White-T · Post by **91White-T** » Thu Oct 27, 2005 1:24 am

It will help keep the turbo spooled during shifts, and sound cool. It will do nothing else.

vrg3 · Post by **vrg3** » Thu Oct 27, 2005 1:35 am

Why are you guys saying it will help keep the turbo spooled?

555BCTurbo · Post by **555BCTurbo** » Thu Oct 27, 2005 2:36 am

Yes...vrg3 is right (per usual), both the factory bypass and an aftermarket blowoff do nothing but relieve pressure from the post-turbo intake tract...and prevent the turbo from surging...

Now...on the Porsche 924 Turbos, they had a recirc. valve that did actually help keep the turbo spooled

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blow off valve

blow off valve