To Blow Off Valve or not to Blow Off Valve??

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Originally Posted by Muzz

My opinion - If the 90% of turbo oem cars come with a recirculation valve, when the manurfactures are all focoused on keeping costs down, then theres obviously reason for them using one. They dont just go sticking random parts in there cars, they do testing and evaluating, if it was worthless it wouldnt be there.

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What about a cat converter? Its there for emissions, so is a recirculation valve.

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Garret states that compressor surge is bad for their turbos, what have you got to show them to be wrong?

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People who have not rebuilt their turbos after 4-5 years of dosing.

Im not saying it doesnt do any damage, im just saying its so little, its not worth worrying.


Also, you keep neglecting my evidence.

Nizpro doesnt use them, responsible for the 1153hp xr6t, and you would think at those heat levels, premature wearing should be exaggerated.

Prodrive, the guys that run the subaru WRC car, and various other race cars, seem to think its unnecessary in the road going concept.

The guys responible for the Aqua subaru dont seem to think that its needed.

Many people on calaisturbo have been dosing for years without rebuilding turbos. Youd think they would stop dosing if it was so clear that it damaged turbos.

O, and my friends, have been dosing for years now, i we've yet to rebuild a turbo.

LOL Muzz, you're taking this too far. Garrett says it themselves, CAN cause damage when in CONTINUOUS or LONG PERIODS of time in the surge region. Surging under no load quickly between gears is neither of those things. Generalized FAQ answers is not SOLID PROOF of anything. Consider the forces involved between continuous operating in the surge region versus a little bit of chatter from your charge pipes filled with some boost. Got negligible?

Also please get off your high horse about everyone's knowledge. You've done one fluid mechanics course and you think you know it all? Please... Leave your comments on education at the door and concentrate on the discussion not those discussing it.

seriously reading this has made me more confused then wen i started LOL

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Originally Posted by gReY-oNe

seriously reading this has made me more confused then wen i started LOL

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I do you think I feel, I asked the question lol

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Originally Posted by Lukezen27

I do you think I feel, I asked the question lol

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HAR HAR HAR ive been following this thread
cos i was wondering the same thing
now im confused and have no idea wat to do LMAO

o btw, ive done fluid at uni too ;)

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Originally Posted by gReY-oNe

seriously reading this has made me more confused then wen i started LOL

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OK, ill try and clear things up.

It does wear your turbo (so does normal use) BUT how much, no one seems to really know.

Some people say a lot while some people say its so little its not even worth considering (and i dont mean bob off the internet, i mean large companies that have the money to invest in R&D)

The only evidence we really have, is through trial. Now people on calaisturbo have been dosing for years, and many say that they havent rebuilt their turbos in years.

BUT, there is also people on calaisturbo who attribute their turbos failure to dosing. Only problem is, is that these failure can also be attributed to other causes.

SO, what u can do

- Fit a cheap bov $50. But these often leak, causing power loss and more headaches

- Fit a decent bov $400. Shouldnt leak, and should last a few years. Evantually do wear and start to leak.

- Dont fit anything. $0. BUT may cause premature failure. So it might cost a rebuild. ($400-700). Remember turbos do wear and all will eventually need a rebuild. Think of it as an excuse to hiflow ;)

^^^ lmao
thanks for clearing that up

plus i brought one already anyway LOL

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Originally Posted by gReY-oNe

^^^ lmao
thanks for clearing that up

plus i brought one already anyway LOL

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lol yeah

what model did you buy?

Cheap or ....

i picked it up from my friends friend
an apexi twin chamber one
i wouldnt say its the best but it dus its job

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Originally Posted by aimre

Im not saying it doesnt do any damage, im just saying its so little, its not worth worrying.

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That is a totally perfect and legit opinion, and I can see what your saying 200%.
I think you guys have totally taken what ive said so far, completely in the wrong context.

See this is exactly what I was saying in my very 1st post, it really all just comes down to your own personal opinions, and values.

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Run one if you like the noise or you want your turbo to be working in the best possible conditions, and the extra cost dosnt bother you.

Dont run one, if you dont like the "psssshhhh", you like the dose sound, or your happy to risk maby reducing your turbos working life, to save some cash.

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(Please note the above word “maby”)

I’m the kind of person that wants every thing working exactly as intended, I would like to know that my turbo is working in the best conditions I can give it. If I can eliminate it from having to deal with it regularly seeing surge conditions for a reasonable price, I will.
I guess you could say, I value long service life mostly, and I do. I want my setup to run like an oem designed system, with everything working exactly as intended.

You seem to be the kind of person that isn’t going to spend his money on a product that he will never really see much of a benefit from. And when it really comes down to it, you aren’t, the downside being that your turbo will be exposed to harsher conditions, which may, or may not effect turbo life. And as I’ve stated, NONE of us have the knowledge to say how much it will.

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Originally Posted by aimre

It does wear your turbo (so does normal use) BUT how much, no one seems to really know.

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Exactly.

Add to that the fact that every system is different, each turbo is different, everyone’s running different psi levels, power levels, airflow rates, the compressor graphs are different, different turbos will be more vulnerable to damage from surge, times spent in surge between systems will be different, etc, etc, etc.

On some systems, a bov may be completely and utterly pointless, while on others it may be very necessary to prevent excessive wear. Weather or not a bov is useful depends greatly on the setup.

We don’t know how much surge will effect the turbo, only that turbos don’t like surge conditions.
Again, I’ve never stated that a bov will greatly effect the turbo’s lifespan, all ive been stating is that it’s a solid fact, that surge conditions are bad for the turbo.

I’m not saying my setup will be better than yours or anything at all like that, there’s no such thing, its all a matter of view.
For me, my setups better because I can drive around, knowing than my turbochargers as happy as it can possibly be under the bonnet. Its not being exposed to detrimental conditions so theres no worries of any negative effects that may be caused from the repetative surging.

For you, your setups better because you havnt wasted money on a part that really isn’t going to effect much at all, especially performance wise. And why not, as you’ve stated you know plenty of people running without one successfully. On top of that you also enjoy the sound of not running one. Not to mention not running one saves cash for other mods.

As I stated in my 1st post, it’s ALL a matter of values, and opinions. We all have different values, my values call for me to get a bov, yours call for you to pass, spend that money elsewhere.

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Nizpro doesnt use them, responsible for the 1153hp xr6t, and you would think at those heat levels, premature wearing should be exaggerated.

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True, but then again, maybe they feel it’s not worth the trade off between the extra weight, and the longevity of the turbo, there could be plenty of reasons why they feel better off without one.
I cant imagine a car of this level will be using the same turbo all they way to the end of its lifespan due to wear, bov or not.
Plus I’m sure they have a decent budget, so slightly accelerated wear would probably be less of an issue.

Again, the question of weather or not to run a bov comes down to what you value, and your objectives for the car.

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Prodrive, the guys that run the subaru WRC car, and various other race cars, seem to think its unnecessary in the road going concept.

The guys responible for the Aqua subaru dont seem to think that its needed.

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Fair enough, obviously every turbo system not running one is doing so for a reason. Weather it be for cost reasons, no measurable benefits in performance at a cost in weight, no measurable benefits in turbo life, or whatever, we cant say.

Just because various different cars have chosen to leave a bov out of the system, doesn’t automatically mean their doing so because there’s no effect at all on the turbochargers lifespan.:thumbsup:

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Originally Posted by aimre

The only evidence we really have, is through trial. Now people on calaisturbo have been dosing for years, and many say that they havent rebuilt their turbos in years.

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True, and while it does give an ok indication, that a turbo can deal ok with slight surge conditions, its not enough to say with a bov on X engine, the turbo lasted 180,000kms before needing a rebuild, and on the same engine, in simular driving conditions, without a bov the turbo only lasted 155,000kms.