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Old 05-30-2004, 01:26 PM   #1
masiolli
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Join Date: Apr 2003
Location: Youngstown, Oh
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1999 Blue RS-t
22t & Hydra

Default RS-t related question...

Sorry if these are n00b questions.. but they've been bothering me cause i dont know why its like this..

ok first off.... how come my car doesnt make boost in neutral? I know someone with a 02 WRX, and he can rev it, and let off the gas and his BOV goes off... but mine stops at 0PSI... i dont really care so dont flame me for wanting to hear my BOV work... i'm just confused on why mine is like that...

second: How come my BOV only goes off when the car is in neutral.. by this i mean... im in first, i floor it, make boost... let off the gas.. nothing.. i do the same thing, but this time, when i let off the gas, i put it in neutral... my BOV vents... why does is doing this? i thought the BOV vented the air when the throttle body closed... i have a feeling it has something to do with the vacuum system (which i completely dont understand..).

Thanks for the help... again... forgive my n00biness...
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Old 05-30-2004, 01:31 PM   #2
White 2.5rs
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99RS TWE&SCAT EJ257
Hydra+HMist+PPG+35R=DEATH

Default

its in ur head man, im not joking

that not blowing w/ just revving might be a characteristic of ur turbo setup/piping

Last edited by White 2.5rs; 05-30-2004 at 01:45 PM.
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Old 05-30-2004, 01:34 PM   #3
masiolli
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1999 Blue RS-t
22t & Hydra

Default

so do all the RS-t's do this? or is mine wrong? cause i bought it with the turbo kit on (minnam stage 2) and the guy who put it on didnt do the best job....
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Old 05-30-2004, 01:47 PM   #4
Unsung Boxer
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Default

the Blow off valve works like this:

1. Spring pressure helps hold the valve shut.
2. Vacuum line sucks valve open under hard vacuum.
3. Boost pressure pushes valve open from other side.

Everyone forgets number 3.

What im getting at is that your BOV will only open when there is a significant "change in" pressure.

Its hard to get the BOV to blow in neutral. You usually have to goose the gas pedal. If spring pressure is too high, or you are using a poor vacuum source, it might not go. Its not really necessary for it to blow in neutral revving.

If its not blowing off in normal shifting, you are going to have to address the 3 things that make it work. Most likely the spring is set too tightly.

-Jake
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Old 05-30-2004, 07:22 PM   #5
Avenger
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2000

Default

Quote:
ok first off.... how come my car doesnt make boost in neutral? I know someone with a 02 WRX, and he can rev it, and let off the gas and his BOV goes off... but mine stops at 0PSI... i dont really care so dont flame me for wanting to hear my BOV work... i'm just confused on why mine is like that...
Your turbo is a t3/t4, it is a fairly big turbo and takes more exhaust to get it spooling. Whereas the turbo on the wrx is smaller and it doesn't take as much exhaust to get the turbo to spool up and create boost.
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Old 05-30-2004, 07:45 PM   #6
kaos200
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Quote:
Originally posted by Avenger
Your turbo is a t3/t4, it is a fairly big turbo and takes more exhaust to get it spooling. Whereas the turbo on the wrx is smaller and it doesn't take as much exhaust to get the turbo to spool up and create boost.
in short
baby turbos blow off easy
big boy turbos dont
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Old 06-01-2004, 05:35 PM   #7
masiolli
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22t & Hydra

Default

so do all the RS-t's do this?
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Old 06-01-2004, 06:22 PM   #8
Hitokiri
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1999 2.5RSt
RBP

Default

Quote:
Originally posted by kaos200
in short
baby turbos blow off easy
big boy turbos dont
well, Like Kaos200 said. If you have a large enough turbo so that it does not produce enough pressure in neutral to cause the BOV to open, then you won't hear the valve open.

If you have a WRX turbo powering your RSt, chances are it will spool a little and provide enough pressure to open the BOV, thus producing the noise.

But there are many factors that go into whether the BOV opens including many aspects of the turbo setup. An "RSt" can be setup many different ways producing different results.

So to finally answer your question:
no RSt's don't all behave like you described. Some will blow off and some won't.
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Old 06-01-2004, 06:25 PM   #9
masiolli
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22t & Hydra

Default

alright... i just wanted to know if something wasnt hooked up right
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