GN and bov's???

[thenasty6]

ive been told by many that have GN or T TYPEs and ive also never ran one on mine (bov)but talked with alot of freinds with tuner turbocharged cars and they tell me that every turbo charged car needs a BOV.
So my question is what makes my GN so different that it dosent need to run a BOV?....

 

[killer231olds]

Its basically a pressure relief valve like on an air compressor set to go off at a specific pressure/boost level. From what Ive read they were mostly for turbo cars due to after a quarter mile pass they would develope high amounts of boost after the pass but upon letting off the throttle the boost pressure is still built up resulting in boost shudder. It can be in a way an insurance policy if you run it at high boost level. However as far as "tuner dweebs" go most of the ones I saw in school had them set to low to make the cool whoosh sound so here they have a big turbo that never goes past 10 psi cause they want it to go off everytime they shift so in reality they didnt gain anything other than a cool sound and motor not running to its true potential. So if you do run it just make sure to set it to go off at the right pressure/boost level.

 

[killer231olds]

Just think of a tea kettle when the water boils or when you had to much chili and cant find a restroom..pressure needs to be relieved. So to answer your question do you need one? All depends on your combination and what your doing with it. Would I run one on a 9 second drag car yes, on a stock 12 second daily driver probably not but hey thats for you to decide. And if all turbo vehicles needed them they would come with them already..stay away from "tunerds"

 

[Red C5]

If you want to more confused than ever, search on the subject. You will hear from both sides why one is needed or NOT needed. I have been told by people in the industry much smarter than I, that you really need a bov on manual cars, automatic cars don't need them.

 

[Eazy-E]

I run a tial 50mm on my car and i also run a turbo saver. It might be overkill but a little added protection never hurt anyone.

 

[MikeL.]

I have one on mine (came with intercooler/pipes that I bought off this board) and, like mentioned above, is insurance or at least help prolong turbo life. I don't have to explain how expensive replacing turbo's can be. Opinions range on weather it's needed or effectiveness but I can think of many other parts that would be a waste of money.

 

[longball]

If you want to more confused than ever, search on the subject. I have been told by people in the industry much smarter than I, that you really need a bov on manual cars, automatic cars don't need them.

I have heard this also from what I consider reliable sources. That being said, I have one on my automatic. Why? Well, that's a long story......

 

[longball]

IIRC, BOV's were designed to help cars with manual transmissions keep the turbo spooled between shifts. GN's with auto trans do
not have this problem.

 

[highboostgn]

I think they help out more on a manuel car too..When you shift you let your foot off the gas and the throttle plate closes with nowhere for all that boost to go. So the vacuum will pull the BOV open and relieve pressure.

 

[longball]

it had something to do with taking your foot off the gas while shifting....something about the turbo stopped spooling when you took your
foot off the gas and had to spool up again?

 

[Blazer406]

It has to do with cavitation...... deadheading......water hammer....... IMHO, on a stock turbo.... not needed..... but I know of a situation (on a lot higher hp car) where the compressor wheel was hurt (read fubar'd) just after a burnout....... when you back off the gas real hard........ several times..... ultimately a BOV was installed... and no more issues.

It is on my list to put on at some point.

 

[killer231olds]

http://en.wikipedia.org/wiki/Blowoff_valve


Hope this helps there is also some books on turbo charging that have more or less the same info.

 

[turbo nasty]

You wont find a turbocharging book that says not to use one.
I wouldnt use the Buick TR community as the gospel on not to run one.
Pretty simple.....In boost...lift off gas...turbo is still compressing air...air column backs up loads the compressor....forces its way back past the compressor whell/housing...in the Buick world some think this is acceptable because they didnt have failure or problems.

Never hear mention of letting the car idle to cool down the center section bearings after running it hard either on this site......another common practice with turbocharged anything that the TR folks never speak of.

 

[L8TRH8R]

You wont find a turbocharging book that says not to use one.
I wouldnt use the Buick TR community as the gospel on not to run one.
Pretty simple.....In boost...lift off gas...turbo is still compressing air...air column backs up loads the compressor....forces its way back past the compressor whell/housing...in the Buick world some think this is acceptable because they didnt have failure or problems.

Never hear mention of letting the car idle to cool down the center section bearings after running it hard either on this site......another common practice with turbocharged anything that the TR folks never speak of.

Yeah I have a turbo timer on my viper alarm that shuts off the car when turbo has cooled.

 

[longball]

Yeah I have a turbo timer on my viper alarm that shuts off the car when turbo has cooled.

that's pretty cool. I live at the end of a long dirt road, gotta go slow, that and I let it idle 2 minutes before shutting it off, been doing that for 20 some years.
seems to be working........

 

[williamsGN]

I just never get into it during the first or last 5 minutes of driving. Sux cause the beer store is only a 5 minute drive.

 

[Homie_Telefrag]

Its been from my experience that a BOV is the biggest scam since the Atari 5200.... >.>

 

[forzfed]

It has to do with cavitation...... deadheading......water hammer....... IMHO, on a stock turbo.... not needed..... but I know of a situation (on a lot higher hp car) where the compressor wheel was hurt (read fubar'd) just after a burnout....... when you back off the gas real hard........ several times..... ultimately a BOV was installed... and no more issues.

It is on my list to put on at some point.

It has to do with surging caused by the difference in supply and system pressure not cavitation. How do you get cavitation with air or water hammer?

 

[Nick Micale]

You wont find a turbocharging book that says not to use one.
I wouldnt use the Buick TR community as the gospel on not to run one.

Pretty simple.....In boost...lift off gas...turbo is still compressing air...air column backs up loads the compressor....forces its way back past the compressor whell/housing...in the Buick world some think this is acceptable because they didnt have failure or problems..............

Jason's comments are true, but I would take it a step further.

With a stock GN, the components are "sized", or maybe designed, to not to have the air column to put loads on the compressor wheel when rapidly closing the throttle blade. When you change this relationship with a larger turbo, better flowing IC, open air filter and other items, you can certainly hear the air column coming to a rapid stop.

In a drag race situation with lots bigger turbos as well as more air flow, rapidly closing the throttle is not normal, and like others, I have been aware and conditioned NOT to do that.

On the street, it is a different situation with larger turbos, and the throttle can be rapidly closed many times, even in just a few blocks.

So my take is if you "mess around" on the street lots with a large turbo, that would be a good candidate for a BOV, for track use, not so much, IF you are aware of how to minimize rapid decell situation.

 

[GW2]

Just to correct some earlier posts, the bov isn't set to go off at specific psi (that's what a Watergate is for) it goes off when you leave boost and return to vacuum. At least that's how it's done on manual trans.