Difference in supercharger BOV and Turbo BOV
#1
12-30-2006, 04:13 PM
Difference in supercharger BOV and Turbo BOV
Im just reading up on some FI trying to learn amore about it and how to better understand it, but what is the difference in the BOV for a supercharger and the BOV for a turbo?
I see that the vortech comes with a BOV, but it doesnt look like the stillen does...how come? Every turbo kit obviosuly comes with one...
Is there a difference in sound of the blow off
Is there a difference in one blow off release vs the other? (earlier or later)
-sean
I see that the vortech comes with a BOV, but it doesnt look like the stillen does...how come? Every turbo kit obviosuly comes with one...
Is there a difference in sound of the blow off
Is there a difference in one blow off release vs the other? (earlier or later)
-sean
#3
12-30-2006, 06:46 PM
#4
12-30-2006, 06:57 PM
#5
12-30-2006, 07:09 PM
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I'm no genius about ALL the different setups [Turbo, Twin Turbo, Roots SC, etc.] and how their blow off valves and wastegates are setup. I'm most comfortable with whats on my car - a centrical type supercharger [like Vortec and ProCharger]. The ProCharger comes with a 'bypass valve', even though it is still run with belts and pulleys the compressor wheel is still spinning very fast and creating airflow if the thottle body snaps shut - needing some type of way for air the be released. Alot of superchargers have a slightly different type of blow off valve that will remain open for longer periods of time, say 3 or 4 seconds depending on certain RPMs and loads compared to say 1 or 2 seconds for a turbo. I believe either way there is a spring or some other type of PSI sensor that once air is forced against it so much it will pop open and release. You can check out www.HowStuffWorks.com and look up blow off valves and it will give you better explanations.
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12-30-2006, 07:39 PM
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12-30-2006, 08:37 PM
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#9
12-30-2006, 09:43 PM
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12-30-2006, 09:50 PM
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Both perform the same function.
It vents the boost psi out from between the compressing means (turbo or blower) and the intake manifold/TB. This is to reduce/relieve "Compressor Surge" which is the build up of psi between the compressing means and the intake upon lifting off the throttle while under boost. The build up of psi causes extra force on the bearings and assoicated parts in the compressing means.
They are needed on turbos especially as they are spinning upwards of 30k rpm (not a typo 30 k) building boost and then you lift off the throttle the sucker(s) is still spinning trying compress air into the motor and the motor no longer has the need for boost and psi builds between the two and the pneumatic signal difference causes the Bypass/blow off valve to actuate and purge air to the atmosphere or back in to the vacum side of compressor inlet.
The purge sound will be greater if veneted to the atmosphere.
As far as the vortech setup goes u could vent the bypass air into the atmosphere and get the sound, though w/ MAF cars that air is calulated and a vent of sorts can cause a rich condition due to the air that is calculated in is vented.
It vents the boost psi out from between the compressing means (turbo or blower) and the intake manifold/TB. This is to reduce/relieve "Compressor Surge" which is the build up of psi between the compressing means and the intake upon lifting off the throttle while under boost. The build up of psi causes extra force on the bearings and assoicated parts in the compressing means.
They are needed on turbos especially as they are spinning upwards of 30k rpm (not a typo 30 k) building boost and then you lift off the throttle the sucker(s) is still spinning trying compress air into the motor and the motor no longer has the need for boost and psi builds between the two and the pneumatic signal difference causes the Bypass/blow off valve to actuate and purge air to the atmosphere or back in to the vacum side of compressor inlet.
The purge sound will be greater if veneted to the atmosphere.
As far as the vortech setup goes u could vent the bypass air into the atmosphere and get the sound, though w/ MAF cars that air is calulated and a vent of sorts can cause a rich condition due to the air that is calculated in is vented.
Last edited by Turbo nasty; 12-30-2006 at 09:54 PM.
#11
12-30-2006, 10:12 PM
The Main difference between the two
[1] Bypass BOV ...that comes with Vortech and other SC's
It stays open under vacuum
the vacuum itself holds the BOV open
when vacuum drops [ giving it gas or going WOT ] the BOV closes allowing boost to build
The boost helps hold the BOV closed
When you let off the gas , vacuum returns and BOV opens again
[2] On a turboed car the BOV stays closed under vacuum
exctly how and when it opens and closes during operation Im not sure on , but I beleive it opens at a set psi to vent when shifting
[1] Bypass BOV ...that comes with Vortech and other SC's
It stays open under vacuum
the vacuum itself holds the BOV open
when vacuum drops [ giving it gas or going WOT ] the BOV closes allowing boost to build
The boost helps hold the BOV closed
When you let off the gas , vacuum returns and BOV opens again
[2] On a turboed car the BOV stays closed under vacuum
exctly how and when it opens and closes during operation Im not sure on , but I beleive it opens at a set psi to vent when shifting
Last edited by booger; 12-30-2006 at 10:15 PM.
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12-30-2006, 10:25 PM
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#13
12-30-2006, 10:27 PM
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Originally Posted by booger
The Main difference between the two
[1] Bypass BOV ...that comes with Vortech and other SC's
It stays open under vacuum
the vacuum itself holds the BOV open
when vacuum drops [ giving it gas or going WOT ] the BOV closes allowing boost to build
The boost helps hold the BOV closed
When you let off the gas , vacuum returns and BOV opens again
[2] On a turboed car the BOV stays closed under vacuum
exctly how and when it opens and closes during operation Im not sure on , but I beleive it opens at a set psi to vent when shifting
[1] Bypass BOV ...that comes with Vortech and other SC's
It stays open under vacuum
the vacuum itself holds the BOV open
when vacuum drops [ giving it gas or going WOT ] the BOV closes allowing boost to build
The boost helps hold the BOV closed
When you let off the gas , vacuum returns and BOV opens again
[2] On a turboed car the BOV stays closed under vacuum
exctly how and when it opens and closes during operation Im not sure on , but I beleive it opens at a set psi to vent when shifting
Straight off of Vortech site.....
"Vortech Maxflow Bypass/Blowoff Valves improve supercharger operations by opening to relieve unwanted pressure during deceleration, this reduces heat build-up and eliminates compressor surge. These units feature a "rolling diaphragm" design which provides ultra-quick valve response along with unmatched reliability"
They both (turbo and blower) are closed under vacum and boost and only open during the psi differential, and work as I wrote above.
If it was open under vacum that would mean you are sucking in unfiltered air to the motor. Look at where the bypass valve is in the system.
#14
12-30-2006, 11:44 PM
so on the vortech system the BOV is working the same as on a turbo or is this with all supercharger systems? With the vortech kid does it still have that same "pshhh" sound or does it have a different noise? With the vortech being a centrifugal supercharger does it still have that same supercharging "winding" noise or does it have more of the characteristics of a turbo?
#15
12-30-2006, 11:45 PM
Originally Posted by Turbo nasty
Booger ...not quite...
Straight off of Vortech site.....
"Vortech Maxflow Bypass/Blowoff Valves improve supercharger operations by opening to relieve unwanted pressure during deceleration, this reduces heat build-up and eliminates compressor surge. These units feature a "rolling diaphragm" design which provides ultra-quick valve response along with unmatched reliability"
They both (turbo and blower) are closed under vacum and boost and only open during the psi differential, and work as I wrote above.
If it was open under vacum that would mean you are sucking in unfiltered air to the motor. Look at where the bypass valve is in the system.
Straight off of Vortech site.....
"Vortech Maxflow Bypass/Blowoff Valves improve supercharger operations by opening to relieve unwanted pressure during deceleration, this reduces heat build-up and eliminates compressor surge. These units feature a "rolling diaphragm" design which provides ultra-quick valve response along with unmatched reliability"
They both (turbo and blower) are closed under vacum and boost and only open during the psi differential, and work as I wrote above.
If it was open under vacum that would mean you are sucking in unfiltered air to the motor. Look at where the bypass valve is in the system.
IT IS OPEN UNDER VACUUM ..ask any one WITH a vortech kit . You ARE NOT SUCKING AIR IN . Vortechs Bypass BOV is between the blower and the IC . So when open , it is venting the air the SC is blowing . OUtside unfiltered air is NEVER being SUCKED IN . Thats why the BOV is whistling at idle , its blowing air out of the BOV . Thats the difference between a normal BOV and a Bypass BOV . One is open under vacuum and one is not . Ive had mine for almost 4 years now . Ive tried normal BOV's and they dont work on a Vortech kit unless you set it up differently .
Last edited by booger; 12-30-2006 at 11:49 PM.