Fact or Fiction - No BOV = Bad?
12-29-2012, 12:22 AM
#1
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Thread Starter
Join Date: 11-20-2012
Location: CT
Posts: 34
Fact or Fiction - No BOV = Bad?
This has been debated a lot as of late. Is a BOV truely a HAVE to? I never see turbo's failing due to compressor surge. MANY high performance cars don't even use them. Not saying I will be removing my BOV, I just want your opinion! 
12-29-2012, 02:20 AM
#2
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Join Date: 10-06-2011
Location: Mesa, AZ
Posts: 1,150
Which hi performance TURBO cars do not use them?
Are you sure that they do not have a BYPASS or RECIRC valve insted?
If you did not have one then when you let off the throttle the compressed air will have no where to go and the blades will be stopped very quickly. This is said to be where a failure can occur. I would not think one time would hurt it but over and over again might. But what will be noticable each time you want to get right back into boost (like during manual shifts during a run) is that the turbo will have to spool up again insted of still being ready, willing and able.
Are you sure that they do not have a BYPASS or RECIRC valve insted?
If you did not have one then when you let off the throttle the compressed air will have no where to go and the blades will be stopped very quickly. This is said to be where a failure can occur. I would not think one time would hurt it but over and over again might. But what will be noticable each time you want to get right back into boost (like during manual shifts during a run) is that the turbo will have to spool up again insted of still being ready, willing and able.
01-01-2013, 04:40 PM
#4
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Join Date: 08-05-2009
Location: Cahokia IL
Posts: 358
Which hi performance TURBO cars do not use them?
Are you sure that they do not have a BYPASS or RECIRC valve insted?
If you did not have one then when you let off the throttle the compressed air will have no where to go and the blades will be stopped very quickly. This is said to be where a failure can occur. I would not think one time would hurt it but over and over again might. But what will be noticable each time you want to get right back into boost (like during manual shifts during a run) is that the turbo will have to spool up again insted of still being ready, willing and able.
Are you sure that they do not have a BYPASS or RECIRC valve insted?
If you did not have one then when you let off the throttle the compressed air will have no where to go and the blades will be stopped very quickly. This is said to be where a failure can occur. I would not think one time would hurt it but over and over again might. But what will be noticable each time you want to get right back into boost (like during manual shifts during a run) is that the turbo will have to spool up again insted of still being ready, willing and able.
Just because it's not labeled as BOV doesn't mean there is not an internal way to dump pressure somewhere...then the excess is fed back into the motor to be burned.
01-03-2013, 10:20 AM
#5
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Join Date: 11-12-2012
Location: Sugar Grove, IL
Posts: 17
This is an age old arguement, BOV's are not a necessary item on a forced induction car, especially a stock or lightly modified motor. Not running one isn't going to hurt your turbo!!!!! Now with that said here is why you may want to run one AND why the HHR SS came from the factory with one.....Performance and fun factor!!! If you know how a turbo works then you'll understand this, it spins at very high rpms while making boost, the bov allows you to keep the turbo at those rpms between shifts otherwise without it the compressor wheel will slow down between shifts and you will have a lag in power until the turbo spools up again. That's pretty much it. If you run a bigger turbo that flows a lot of air then its even a better idea to have one.
01-03-2013, 11:37 AM
#6
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Join Date: 04-03-2009
Location: atlanta, ga
Posts: 707
Running boost over a modest amount say 7psi a bov/bov is needed. Abive modest pressures a turbo will get damaged over a period of time without using one. As stated above the compressed air that is between the turbo anf the throttle body inside the charge pipes has nowhere to go once the throttle is closed. The only place for it to go is where it came from...the turbo. So what happens is it slows down the turbine very abruptly. The higher the boost and more pressure the more abruptly it slows the turbine as the air tries to exit where it came from. Now if when the throttle is closed the air has somewhere else to escspr then there is no harm being done to the turbine. Now imagine this....the turbo us spinning at 100,000+ rpm at 15psi(stock ss) and the throttle closes...what effect is that high boost pressure going to have on tgst turbo that is spinning that fast? No it wont damage it if it happens one time or maybe even 100 times but eventually it will. The experts at garrett have said that under 6-7psi doesnt require a bov but anything over you should use one.
01-04-2013, 09:10 PM
#7
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Join Date: 09-19-2012
Location: North Glendale, AZ
Posts: 70
I am hoping to achieve around 25 or so Pounds of Boost and I understand why you need a way to release the pressure from the system at times and that the HHR SS comes from the factory with a way to deal with the factory pressure level.
My questions are;
1, at what point is it necessary to considering a different way of releasing the pressure
2, what or who’s systems should be considered and has a proven track record.
I had a 930 Porsche with a K-27 Turbo and a 1-Bar spring and just the factory Waste Gate and Waste Gate pipe that vented out the rear of the car into the atmosphere and never had to deal with upgrading the Waste Gate so I’m on a new learning curve here.
My questions are;
1, at what point is it necessary to considering a different way of releasing the pressure
2, what or who’s systems should be considered and has a proven track record.
I had a 930 Porsche with a K-27 Turbo and a 1-Bar spring and just the factory Waste Gate and Waste Gate pipe that vented out the rear of the car into the atmosphere and never had to deal with upgrading the Waste Gate so I’m on a new learning curve here.
01-04-2013, 09:24 PM
#8
Senior Member
Join Date: 10-06-2011
Location: Mesa, AZ
Posts: 1,150
I am hoping to achieve around 25 or so Pounds of Boost and I understand why you need a way to release the pressure from the system at times and that the HHR SS comes from the factory with a way to deal with the factory pressure level.
My questions are;
1, at what point is it necessary to considering a different way of releasing the pressure
2, what or who’s systems should be considered and has a proven track record.
I had a 930 Porsche with a K-27 Turbo and a 1-Bar spring and just the factory Waste Gate and Waste Gate pipe that vented out the rear of the car into the atmosphere and never had to deal with upgrading the Waste Gate so I’m on a new learning curve here.
My questions are;
1, at what point is it necessary to considering a different way of releasing the pressure
2, what or who’s systems should be considered and has a proven track record.
I had a 930 Porsche with a K-27 Turbo and a 1-Bar spring and just the factory Waste Gate and Waste Gate pipe that vented out the rear of the car into the atmosphere and never had to deal with upgrading the Waste Gate so I’m on a new learning curve here.
01-05-2013, 12:29 AM
#9
Senior Member
Join Date: 04-03-2009
Location: atlanta, ga
Posts: 707
I am hoping to achieve around 25 or so Pounds of Boost and I understand why you need a way to release the pressure from the system at times and that the HHR SS comes from the factory with a way to deal with the factory pressure level.
My questions are;
1, at what point is it necessary to considering a different way of releasing the pressure
2, what or who’s systems should be considered and has a proven track record.
I had a 930 Porsche with a K-27 Turbo and a 1-Bar spring and just the factory Waste Gate and Waste Gate pipe that vented out the rear of the car into the atmosphere and never had to deal with upgrading the Waste Gate so I’m on a new learning curve here.
My questions are;
1, at what point is it necessary to considering a different way of releasing the pressure
2, what or who’s systems should be considered and has a proven track record.
I had a 930 Porsche with a K-27 Turbo and a 1-Bar spring and just the factory Waste Gate and Waste Gate pipe that vented out the rear of the car into the atmosphere and never had to deal with upgrading the Waste Gate so I’m on a new learning curve here.
01-05-2013, 02:48 AM
#10
Senior Member
Join Date: 10-06-2011
Location: Mesa, AZ
Posts: 1,150
I get the fealing that many think of a BOV as the atmospheric ones that make the loud sound. Not all BOV's blow off to atmosphere. You can get BOV's that work in a recirc setup. Even the Greddy's have different nozzles that can be put on them to vent to atmosphere or to recirc.