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Discussion Starter #1
On my search I found that some have two BOV´s.

Why is that?

What´s the advantage??

Is that a question of how big a turbo is, or how much boost you run, or what??

Just wanted to know...it´s interesting...

Thanks,
Michael
 

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Austrian Supra said:


Is that a question of how big a turbo is, or how much boost you run, or what??

Yep, On larger single turbo applications, some bovs cant went enough air so two bovs are used. Or you could use one big, like the HKS Racing BOV type II or GReddy Type R.

Krister
 

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I'm going single over the winter and should have around 600whp on high boost (SP-63, fuel, BL kit) and am currently running one HKS SS, should I definetely get another one before I run that much power or will it be ok? I wouldn't want to damage the new turbo due to surge so I'm guessing yes...
 
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Austrian Supra said:
On my search I found that some have two BOV´s.

Why is that?

What´s the advantage??

Is that a question of how big a turbo is, or how much boost you run, or what??

Just wanted to know...it´s interesting...

Thanks,
Michael
I just like scaring the shit out of people with them :D
 

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MarcSMT said:
Can you run 2 BOVs with just BPU? :-D
sure you can, its just not needed
 

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HKS SS blows off 80% of the air the R does.....thats how it was explained to me.
 

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I think the Blitz DDBOV is a really great BOV, it's probably just as loud as the HKS but the sound isn't quite as unique. However, functionally, it works great.
 

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i got the greddy type s bov...is this a good bov, cus i was thinkin of switchin to the HKS...no apparent reason, im only BPU, but i heard a sound clip of the HKS and love it..
 

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Steve Theodore is running a GReddy Type-S on his single turbo which has dynoed around 500rwhp and that valve works fine for him.

As for the comment... "it's rated to 500hp so I have to run 2" ... Blow off valves aren't rated to horsepower- they are rated to a certain pressure. Don't get caught up in if someone says it won't hold that amount of horsepower because it's all relative, one car could build 500hp at 3psi, as where another might build 500hp at 30ps. A blow-off valve is regulated by the pressure of the intake charge.... horsepower is relative to that.

If you've got a big single turbo and only plan on running 7-8psi, then theres no need to get a super stiff BOV spring. Likewise, if you're planning on running over 2bar..... then 2 BOV's with stiff springs would be more effective. :)

CraigK
 

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When I had just one HKS SS BOV it would surge the turbo really bad on high boost runs. With two, it seems to be okay now.
Most small BOVs can't handle the volume of air that a big single put out at high (>20psi) boost.

Here's a pic of my set up
http://www.fototime.com/{07B956F8-07E5-482A-9DF3-AF9B13BB1D16}/picture.JPG
 
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jbsupra95 said:
I have 2 hks ssq bov's. Each hold 500hp so I need 2 since I have more than one can handle.
Does that mean my one hks ss bov is not enough? I have 660rwhp. With a gt66 turbo.
 

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Craig King said:
Steve Theodore is running a GReddy Type-S on his single turbo which has dynoed around 500rwhp and that valve works fine for him.

As for the comment... "it's rated to 500hp so I have to run 2" ... Blow off valves aren't rated to horsepower- they are rated to a certain pressure. Don't get caught up in if someone says it won't hold that amount of horsepower because it's all relative, one car could build 500hp at 3psi, as where another might build 500hp at 30ps. A blow-off valve is regulated by the pressure of the intake charge.... horsepower is relative to that.

If you've got a big single turbo and only plan on running 7-8psi, then theres no need to get a super stiff BOV spring. Likewise, if you're planning on running over 2bar..... then 2 BOV's with stiff springs would be more effective. :)

CraigK
Since Jbsupra94's bov are HKS ssq's their is no "stiff Spring" so the fact that 1 of them still causes compressor surge, using two would be the logical thing.
 

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It isn't horsepower or boost pressure. It is airflow and volume. If you push enough air thru your I/C and pipes, it may not be possible for one BOV to vent it due to the volume of air that needs to be vented in a certian time. Then some air would make it back to the turbo and "surge" the compressor. Then you'd need 2. :)
 

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Ya beat me to it. I agree.

chevyeater-on-sf said:
It isn't horsepower or boost pressure. It is airflow and volume. If you push enough air thru your I/C and pipes, it may not be possible for one BOV to vent it due to the volume of air that needs to be vented in a certian time. Then some air would make it back to the turbo and "surge" the compressor. Then you'd need 2. :)
 
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How much can one tial support i dont recall there being different springs of sizes for tials....
 
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