More BOV questions
01-04-2006, 08:54 AM
#1
More BOV questions
I'm going to order the BOV this week if I can decide on which one to get.
My goal is to quiet down the system as well as make it safer under higher boost levels.
The questions I have are.....
Will I need a 50mm BOV to get rid of all the wastegate flutter sounds?
I have got answers back from some with the 38mm TiAL BOV that still have a small amount of wub-wub-wub-wub sound after closing the throttle under boost.
Which BOV type or brand is the quietest and still works well?
Is there any way to muffle the BOV sound and not affect its performance if I have to use one that is a little louder?
Allot of people seem to like a loud BOV, I do not wish to have even more noises comming from my truck than it already has.
A little more stealth would be nice.
This is a link that has allot of brands to choose from, which would be the better for what I would need? I will try to buy from our sponsors if possible.
http://www.slowboyracing.com/shop.ph...24911f18561f41
My goal is to quiet down the system as well as make it safer under higher boost levels.
The questions I have are.....
Will I need a 50mm BOV to get rid of all the wastegate flutter sounds?
I have got answers back from some with the 38mm TiAL BOV that still have a small amount of wub-wub-wub-wub sound after closing the throttle under boost.
Which BOV type or brand is the quietest and still works well?
Is there any way to muffle the BOV sound and not affect its performance if I have to use one that is a little louder?
Allot of people seem to like a loud BOV, I do not wish to have even more noises comming from my truck than it already has.
A little more stealth would be nice.
This is a link that has allot of brands to choose from, which would be the better for what I would need? I will try to buy from our sponsors if possible.
http://www.slowboyracing.com/shop.ph...24911f18561f41
01-04-2006, 09:09 AM
#2
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We always use the Tial. It works well, looks good, and has a clean sound. Its quiet compared to some, but people will still hear it. I dont thing you can avoid that with any bov.
01-04-2006, 09:29 AM
#3
Originally Posted by trtturbo
We always use the Tial. It works well, looks good, and has a clean sound. Its quiet compared to some, but people will still hear it. I dont thing you can avoid that with any bov.
That's what I figured but some are advertized as "LOUD" or "your friends will hear you comming" or "attract as many COPS as you want"
01-04-2006, 04:50 PM
#4
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The bov won't stop the wg sounds unless you run the boost over the bov's limit. Then the bov comes into play.
The bov's job is to prevent too high a pressure, kinda like a safety fuse in the event that the wg gets stuck closed. This happened to a customer of mine in MA when the condensation in his wg's vacuum/boost line froze.
The wg's job is to regulate the boost under normal (boosted) conditions. So the noise will always be there whether you have a bov or not.
The bov's job is to prevent too high a pressure, kinda like a safety fuse in the event that the wg gets stuck closed. This happened to a customer of mine in MA when the condensation in his wg's vacuum/boost line froze.
The wg's job is to regulate the boost under normal (boosted) conditions. So the noise will always be there whether you have a bov or not.
01-05-2006, 06:17 AM
#5
Originally Posted by kenihemi
The bov won't stop the wg sounds unless you run the boost over the bov's limit. Then the bov comes into play.
The bov's job is to prevent too high a pressure, kinda like a safety fuse in the event that the wg gets stuck closed. This happened to a customer of mine in MA when the condensation in his wg's vacuum/boost line froze.
The wg's job is to regulate the boost under normal (boosted) conditions. So the noise will always be there whether you have a bov or not.
The bov's job is to prevent too high a pressure, kinda like a safety fuse in the event that the wg gets stuck closed. This happened to a customer of mine in MA when the condensation in his wg's vacuum/boost line froze.
The wg's job is to regulate the boost under normal (boosted) conditions. So the noise will always be there whether you have a bov or not.
Thanks for the info, it seems I get some conflicting info when asking about BOVs.
I was being told that using a BOV would not stop overboosting in this thread.
https://www.performancetrucks.net/fo...d.php?t=354997
Is this true or not?
Lets say my wastegate is frozen so it cannot vent properly, would the BOV vent anything above the max I have it set for, or is it only active after you shut the throttle like the wastegate reacts?
I know the wastegate is actually limiting or controlling boost as well, but does a BOV only blow off when you close the throttle to releive the intake side of the system's pressure?
I'm either totally dense on this or am getting two sided information or not all the information.
Think I just might have to get a book on turbo's and read up on all this stuff to be sure.
Thanks again everyone. Sorry for being such a TARD!
I need to stop saying that the wastegate is making the wub-wub sound since its really compressor surge.
Last edited by TG02Z71; 01-05-2006 at 08:43 AM.
01-05-2006, 09:10 AM
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A good book is Maximum Boost by Corky Bell. It's not the most current book on turbos, but its very informative. He doesn't go too into depth on BOV's but he does tell you how they work.
A BOV will only open when the engine is under vacuum. When you slam the throttle shut, the engine pulls vacuum. So there's a port on all BOV's that taps into a vacuum source. So when vacuum is present it pulls the valve up and opens it, allowing the boost to escape. But when boost is present, the pressure on the bottom side of the valve, and a spring keep it shut. I don't know who is telling you otherwise, but a BOV does not and cannot controll boost in anyway. If it did, it would be very "bass-akwards" IMO, because it would be controlling the boost after the compressor did the work to create it.
A BOV will only open when the engine is under vacuum. When you slam the throttle shut, the engine pulls vacuum. So there's a port on all BOV's that taps into a vacuum source. So when vacuum is present it pulls the valve up and opens it, allowing the boost to escape. But when boost is present, the pressure on the bottom side of the valve, and a spring keep it shut. I don't know who is telling you otherwise, but a BOV does not and cannot controll boost in anyway. If it did, it would be very "bass-akwards" IMO, because it would be controlling the boost after the compressor did the work to create it.
01-05-2006, 09:43 AM
#7
Originally Posted by vanillagorilla
A good book is Maximum Boost by Corky Bell. It's not the most current book on turbos, but its very informative. He doesn't go too into depth on BOV's but he does tell you how they work.
A BOV will only open when the engine is under vacuum. When you slam the throttle shut, the engine pulls vacuum. So there's a port on all BOV's that taps into a vacuum source. So when vacuum is present it pulls the valve up and opens it, allowing the boost to escape. But when boost is present, the pressure on the bottom side of the valve, and a spring keep it shut. I don't know who is telling you otherwise, but a BOV does not and cannot controll boost in anyway. If it did, it would be very "bass-akwards" IMO, because it would be controlling the boost after the compressor did the work to create it.
A BOV will only open when the engine is under vacuum. When you slam the throttle shut, the engine pulls vacuum. So there's a port on all BOV's that taps into a vacuum source. So when vacuum is present it pulls the valve up and opens it, allowing the boost to escape. But when boost is present, the pressure on the bottom side of the valve, and a spring keep it shut. I don't know who is telling you otherwise, but a BOV does not and cannot controll boost in anyway. If it did, it would be very "bass-akwards" IMO, because it would be controlling the boost after the compressor did the work to create it.
Its been a misunderstanding from my viewpoint all the time and I appologize to everyone for athe repeated questions on the same subject.
Thanks for your patience all!
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01-05-2006, 10:00 AM
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What vanillagorilla said: I wrote all this before I read his post and could not bring myself to just erase it.
I do not think a BOV will ever open under boost even when you are overboosting. It has the pressure of the spring holding it closed plus the boost through the vacuum/boost reference line holding it closed. The more boost you make the more boost there is trying to hold it closed. A BOV should only open when the throttle is closed and the engine is generating enough vacuum to overcome the spring in the BOV. Otherwise it would just bleed off the boost while you are trying to build it.
I do not think a BOV will ever open under boost even when you are overboosting. It has the pressure of the spring holding it closed plus the boost through the vacuum/boost reference line holding it closed. The more boost you make the more boost there is trying to hold it closed. A BOV should only open when the throttle is closed and the engine is generating enough vacuum to overcome the spring in the BOV. Otherwise it would just bleed off the boost while you are trying to build it.
01-05-2006, 11:05 AM
#9
Originally Posted by Mort
What vanillagorilla said: I wrote all this before I read his post and could not bring myself to just erase it.
I do not think a BOV will ever open under boost even when you are overboosting. It has the pressure of the spring holding it closed plus the boost through the vacuum/boost reference line holding it closed. The more boost you make the more boost there is trying to hold it closed. A BOV should only open when the throttle is closed and the engine is generating enough vacuum to overcome the spring in the BOV. Otherwise it would just bleed off the boost while you are trying to build it.
I do not think a BOV will ever open under boost even when you are overboosting. It has the pressure of the spring holding it closed plus the boost through the vacuum/boost reference line holding it closed. The more boost you make the more boost there is trying to hold it closed. A BOV should only open when the throttle is closed and the engine is generating enough vacuum to overcome the spring in the BOV. Otherwise it would just bleed off the boost while you are trying to build it.
I feel like a total dumbass now.
It's the only opens under vacuum part that explains it all for me.
So if I'm running 5psi and let off the throttle it should diminish the compressor surge noise a little better than if I'm running 10 psi of boost?
Would that be something I could expect or is it just not the case?
I'm hoping the BOV will limit the compressor surge to something that will help my turbine survive or just not be subjected to that level of abuse.
I know people with manual transmissions have to go to a BOV set up because boost will increase between shifts with bad results.
If there is a better explanation for that throw it out there.
Thanks again you guys.
01-05-2006, 11:46 AM
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STS told me that compressor surge was not that big of a problem unless you are making 12 - 15 PSI of boost. Then it is very hard on the compressor fins and maybe the shaft. You will never get rid of compressor surge all together because of the delay in the BOV operation. If you have a compressor that creates surge when you abruptly close the throttle then you will always have some AFAIK.
When you close the throttle the engine goes into deceleration and creates enough vacuum to open the BOV. I have to close the throttle completely for the engine to generate enough vacuum to open the BOV on the 6.0L. The spring in the STS TiAL BOV is set at -11 psi and the vacuum in my engine goes to -11.XX psi under deceleration. This should open the BOV and vent the excess pressure generated by the compressor and closed throttle plate to the atmosphere. It takes a second for this to happen so you will still get a little compressor surge before the BOV opens and allows the pressure in the intake to vent. I still hear some compressor surge and have a hard time hearing anything from the BOV from inside the truck. I assume it is working properly and reducing the pressure and abuse on the compressor fins and throttle plate but just that it has a little lag in it's operation.
When you close the throttle the engine goes into deceleration and creates enough vacuum to open the BOV. I have to close the throttle completely for the engine to generate enough vacuum to open the BOV on the 6.0L. The spring in the STS TiAL BOV is set at -11 psi and the vacuum in my engine goes to -11.XX psi under deceleration. This should open the BOV and vent the excess pressure generated by the compressor and closed throttle plate to the atmosphere. It takes a second for this to happen so you will still get a little compressor surge before the BOV opens and allows the pressure in the intake to vent. I still hear some compressor surge and have a hard time hearing anything from the BOV from inside the truck. I assume it is working properly and reducing the pressure and abuse on the compressor fins and throttle plate but just that it has a little lag in it's operation.