Bovs : To Use It Or Not , U Judge!!
11-19-07, 01:34 AM
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Bovs : To Use It Or Not , U Judge!!
Guys , check this thread out ! my old friend is at it again ! I will not give my opinion because I do not want to be banned again ! U be the judge
http://www.ausrotary.com/viewtopic.p...3ea1ebbf6305ad
This one too , http://www.ausrotary.com/viewtopic.p...1064f30f0f3102
http://www.ausrotary.com/viewtopic.p...3ea1ebbf6305ad
This one too , http://www.ausrotary.com/viewtopic.p...1064f30f0f3102
11-19-07, 02:19 AM
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Guys , check this thread out ! my old friend is at it again ! I will not give my opinion because I do not want to be banned again ! U be the judge
http://www.ausrotary.com/viewtopic.p...3ea1ebbf6305ad
This one too , http://www.ausrotary.com/viewtopic.p...1064f30f0f3102
http://www.ausrotary.com/viewtopic.p...3ea1ebbf6305ad
This one too , http://www.ausrotary.com/viewtopic.p...1064f30f0f3102
What's the point in posting this thread but won't give an opinion because you don't want to be banned? When you say your old friend is at it again. His last post on 1st thread was Sept 2006, his last post on the 2nd thread was Jan 2007
hardly current affiars. If you want a discussion on bov are they a waste or not, then start a thread on it. It seems like you have some kind of fixation with Rice because he has a strong opinion on certain topics, so what ?
Do you want to discuss bov or someone elses opinion on bov?
If you start a thread just on bov and give your opinion, then you won't have to be concerned about being banned.
Brian
11-19-07, 06:54 PM
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What's the point in posting this thread but won't give an opinion because you don't want to be banned? When you say your old friend is at it again. His last post on 1st thread was Sept 2006, his last post on the 2nd thread was Jan 2007
hardly current affiars. If you want a discussion on bov are they a waste or not, then start a thread on it. It seems like you have some kind of fixation with Rice because he has a strong opinion on certain topics, so what ?
Do you want to discuss bov or someone elses opinion on bov?
If you start a thread just on bov and give your opinion, then you won't have to be concerned about being banned.
Brian
hardly current affiars. If you want a discussion on bov are they a waste or not, then start a thread on it. It seems like you have some kind of fixation with Rice because he has a strong opinion on certain topics, so what ?
Do you want to discuss bov or someone elses opinion on bov?
If you start a thread just on bov and give your opinion, then you won't have to be concerned about being banned.
Brian
I gave an opinion on that forum and I can give mine now , which is that I know for a fact that surge is bad and it destroys turbos and that I WILL be keeping my pair of BOv's . I have no fixation on Rice , but it seems we are both members on some of the same forums , so I regularly come across his posts /threads , thats all ! I saw no point in restarting a thread from scratch when there is already one going (wheather its on another forum or not) ! I am concerned about being banned , because I have already experienced what happens when you disagree with the guy , and I am not one to wimp out when some one gets in my face , so I guess sooner or later , the fireworks are bound to fly, I would much prefer to avoid the confrontations and personal attacks , That is why I didnt want to comment !
11-20-07, 01:27 AM
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I have had quite a few rx7's with single turbos some with some without bov. The difficulty is determining the cause of a turbo failure sometimes. I had a to4rtubro with no bov valve after about 15,000 miles of hard use and quite a few drag races it had huge shaft play, whether that was because of the abuse or no bov valve is kind of impossible to know. I have a t88 that has approx 20,000 miles with no bov and that turbo seems as good as new. It could be chance why it hasn't gone yet style of driving or maybe that they really aren't needed??
Brian
Brian
11-20-07, 05:37 AM
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As i explained on the other forum , my work involves the use of huge steam turbine driven multistaged , multi cased centrifugal compressors , I have seen and experienced first hand , what surge can do to them and the lengths the manufacturers have gone to eliminate the problem . Its the same thing that happens to a turbo but on a smaller scale !
Yeah I know , people are saying that they dont use them in racing , but 99% of the time the throttle is wide open in a race car , comparing everyday driving to that is just rediculous , you dont change tyres like a race car does , do you ? so why would someone want to compare both driving styles and set up their car like an all out race car ?
What I cannot understand is , why would anyone want to risk their $2500 piece of hardware (well in my case anyway) when using a $200 part is known to be the solution , I mean its just logic and plain common sense , the pressurezed air has to go some place ! weather the actual volume of air is small or not , the actual pressure is huge ! remember its POUNDS PER SQUARE INCH ! Because of my work I have also been fortunate enough to see how the top of a huge 50 metric tonne storage tank is installed during its construction , the floor is built then the domed roof and the walls buit around the roof lastly , the they use 5 psi ! yes 5 psi ! of air pressure to pressurize it and float the roof baybe a two hundred feet in the air ! that is what only 5 psi of pressure can do.
Yeah I know , people are saying that they dont use them in racing , but 99% of the time the throttle is wide open in a race car , comparing everyday driving to that is just rediculous , you dont change tyres like a race car does , do you ? so why would someone want to compare both driving styles and set up their car like an all out race car ?
What I cannot understand is , why would anyone want to risk their $2500 piece of hardware (well in my case anyway) when using a $200 part is known to be the solution , I mean its just logic and plain common sense , the pressurezed air has to go some place ! weather the actual volume of air is small or not , the actual pressure is huge ! remember its POUNDS PER SQUARE INCH ! Because of my work I have also been fortunate enough to see how the top of a huge 50 metric tonne storage tank is installed during its construction , the floor is built then the domed roof and the walls buit around the roof lastly , the they use 5 psi ! yes 5 psi ! of air pressure to pressurize it and float the roof baybe a two hundred feet in the air ! that is what only 5 psi of pressure can do.
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11-20-07, 06:16 AM
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As i explained on the other forum , my work involves the use of huge steam turbine driven multistaged , multi cased centrifugal compressors , I have seen and experienced first hand , what surge can do to them and the lengths the manufacturers have gone to eliminate the problem . Its the same thing that happens to a turbo but on a smaller scale !
Yeah I know , people are saying that they dont use them in racing , but 99% of the time the throttle is wide open in a race car , comparing everyday driving to that is just rediculous , you dont change tyres like a race car does , do you ? so why would someone want to compare both driving styles and set up their car like an all out race car ?
What I cannot understand is , why would anyone want to risk their $2500 piece of hardware (well in my case anyway) when using a $200 part is known to be the solution , I mean its just logic and plain common sense , the pressurezed air has to go some place ! weather the actual volume of air is small or not , the actual pressure is huge ! remember its POUNDS PER SQUARE INCH ! Because of my work I have also been fortunate enough to see how the top of a huge 50 metric tonne storage tank is installed during its construction , the floor is built then the domed roof and the walls buit around the roof lastly , the they use 5 psi ! yes 5 psi ! of air pressure to pressurize it and float the roof baybe a two hundred feet in the air ! that is what only 5 psi of pressure can do.
Yeah I know , people are saying that they dont use them in racing , but 99% of the time the throttle is wide open in a race car , comparing everyday driving to that is just rediculous , you dont change tyres like a race car does , do you ? so why would someone want to compare both driving styles and set up their car like an all out race car ?
What I cannot understand is , why would anyone want to risk their $2500 piece of hardware (well in my case anyway) when using a $200 part is known to be the solution , I mean its just logic and plain common sense , the pressurezed air has to go some place ! weather the actual volume of air is small or not , the actual pressure is huge ! remember its POUNDS PER SQUARE INCH ! Because of my work I have also been fortunate enough to see how the top of a huge 50 metric tonne storage tank is installed during its construction , the floor is built then the domed roof and the walls buit around the roof lastly , the they use 5 psi ! yes 5 psi ! of air pressure to pressurize it and float the roof baybe a two hundred feet in the air ! that is what only 5 psi of pressure can do.
On the other hand if a turbo is say spinning at 90,000 rpm you come off the throttle and your getting a reading of say 5psi infront of the compressor I guess at 90,000 rpm the 5 psi of reverse pressure will only slightly aid in slowing down the compressor wheel rather than actually causing any kind of damage.
I guess it depends on the amount reverse pressure your actually seeing to how much damage it causes.
I have no hard facts to support the next theory but just a thought!
If running around stock to medium boost say 15-16psi I can't see this being an issue. Reason being if you run 15 psi boost, the air is forced from the turbo through the intercooler. By the time you measure the boost under wot at the manifold with the pressure loss it's probably around say 12psi. The only reason the pressure loss is 3-4 psi is becausing of the sustained 15psi coming out the turbo. When you back off the throttle what was once 12psi at the manifold after pressure loss is now vacuum, the air has to go somewhere, so we say it goes back to the compressor, however not under 12psi. Because there is no pressure to force the air back through the intercooler to the turbo, you will have a much larger pressure drop of the air going back towards the turbo as it no longer has 12psi of force behind it by the time the air comes out the other side of the intecooler I would be suprised to see even 2 psi.
Brian
11-26-07, 02:18 AM
#14
A wastegate, no matter how effective, can not eliminate the necessity for a BOV. A wastegate can only relieve backpressure from the turbo, which actually exascerbates the problem inherent to a no-BOV system(front pressure).
When you let off the gas under boost the compressor will continue to spin and build boost between itself and the closed throttle body until the force of the compressed air in front of the turbo is greater than the combined force of the exhaust pressure and momentum of the spinning CHRA.
When the pressure of boost is greater than the absent exhaust pressure(thanks to the wastegate trying to replace the BOV) and the force generated by the momentum of the rotating assembly(which is a lot at 150,000rpm's) the compresser wheel and everything on the adjoining shaft will bounce off of the compressed air(instantly and violently, I might add).
Modern turbocharger and metalurgy technology has made it possible to bounce your turbo and detonate on apex seals multipe times before failure. But, I like to look at it like this:
Running a turbo car witout a BOV is like smoking cigarettes at the gas pump; you will get away with it for a while.
When you let off the gas under boost the compressor will continue to spin and build boost between itself and the closed throttle body until the force of the compressed air in front of the turbo is greater than the combined force of the exhaust pressure and momentum of the spinning CHRA.
When the pressure of boost is greater than the absent exhaust pressure(thanks to the wastegate trying to replace the BOV) and the force generated by the momentum of the rotating assembly(which is a lot at 150,000rpm's) the compresser wheel and everything on the adjoining shaft will bounce off of the compressed air(instantly and violently, I might add).
Modern turbocharger and metalurgy technology has made it possible to bounce your turbo and detonate on apex seals multipe times before failure. But, I like to look at it like this:
Running a turbo car witout a BOV is like smoking cigarettes at the gas pump; you will get away with it for a while.
11-26-07, 06:21 PM
#20
11-26-07, 07:00 PM
#22
What's the point??
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11-26-07, 07:55 PM
#23
Oh that... My buddy had the greddy kit on his 8, didnt have a bov on it due to the flange not being included in the kit so he drove it for a few days without it. Sounded funny, was a sound i've never heard before.
