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

[Lukezen27]

^^^ lmao
thanks for clearing that up

plus i brought one already anyway LOL

lol yeah

what model did you buy?

Cheap or ....

[gReY-oNe]

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

[Muzz]

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

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.

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.

(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.

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

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.

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

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.

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.

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.

[Muzz]

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.

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.

[aimre]

Here, ill add to mre confusion.

http://www.youtube.com/watch?v=OtMmze0KM6Q

At about 20 sec in, youll hear the Audi drive past, and u can hear it dose. But then at 50 sec, when the lancia drives past, it sound like its got a BOV.

Although audi won both constructors and drivers championship

BTW, there a bad accident in that, which marked an end to Group B rallying.... its safe to watch the first 1.20 min

[aimre]

http://www.youtube.com/watch?v=quDX36WJM7k

some more dosing rally cars

5 min in and its all about the lancia... lots of BOV noises

http://www.youtube.com/watch?v=tdgkmirNPf8

O btw, these cars were 4 sec slower than f1 cars of the time, which were making over 1000hp from theit 1.5L engines

[Muzz]

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?

Hahahahhahahhaha you’re funny.
High horse? Wouldn’t that imply that I think I know more than you guys?

unless you’ve studied fluid dynamics to a very high level which none of us have.

Infact, id even go as far as to say that, im the one who understands how very extremely little I actually know.

none of us here can even BEGIN to understand

as I’ve stated, NONE of us have the knowledge

We don’t know how much surge will effect the turbo

I’m not saying my setup will be better than yours or anything at all like that

^^Yes clearly I’m under the impression I know more than everyone else, everything ive said screams it out hey.
BTW, I haven’t done a fluid dynamics course, never implied I did????

Please... Leave your comments on education at the door and concentrate on the discussion not those discussing it.

do you understand how the surging air effects the turbines mechanicals? Im guessing not, which really dosnt make what your saying any more than an uneducated opinion

I never said anything about Aimre's Education. I was stating that he dosnt know exactly how operating in surge is going to effect the parts of the turbo, like the rest of us, so cant really go saying its not going to effect the turbo, as he dosnt have that knowledge. And neither do i which i though was made clear by this statement:

unless you’ve studied fluid dynamics to a very high level which none of us have.

[aimre]

I never said anything about Aimre's Education.

Im guessing not, which really dosnt make what your saying any more than an uneducated opinion, the worst kind there is.

i'll reply further when i get back from uni

[Muzz]

Just read the 1st 6 pages of this thread. Quite a few people have stated that there is zero effect on turbo life from running in an unstable surge condition at every gear change for a split second, like its a fact.

I was just wondering if anyone who has stated this has any actual info to support their claims??
Turbo manurfactures all seem to state that the thrust loads on the shaft when the throttle is snapped shut, can cause accelerated wear of the thrust bearing. I havnt seen anything to prove or disprove this yet. Untill somone can show it dosn't, ill be listening to the people designing these products who say it does.

[DLO01]

I was just wondering if anyone who has stated this has any actual info to support their claims??
Turbo manurfactures all seem to state that the thrust loads on the shaft when the throttle is snapped shut, can cause accelerated wear of the thrust bearing. I havnt seen anything to prove or disprove this yet. Untill somone can show it dosn't, ill be listening to the people designing these products who say it does.

I asked a turbo manufaturer/repairs workshop some questions in regard to Bov's and thier effect on Turbos. Hope this clears up any misconceptions or myths that we may have. This is their response:

I asked **** here the same questions as you've asked me, and although he has seen no 100% positive sign of damage due to no BOV, he still recommends using one for over 10psi of boost pressure when using a Ball Bearing turbocharger.

As for the BOV helping keep the turbocharger spooling, I can definately say this works, as turbocharger reversion would definately cause the turbocharger to reduce spool speed quite rapidly. There may only be a small difference in response time, but there is definately a difference.

This is the best sort of answer your gonna get i think. They way I see it, your gonna have more load on the shaft with more boost you have, so therefore you will get more wear. Simple.

[string]

When turbochargers operate in surge for long periods of time, bearing failures may occur

Please explain to me your interpretations of continuous and continued, and how they relate to Garrett's own words: "long periods of time" (which you so beautifully claimed they did not say).

[string]

10-15 seconds of surge = x ammount of boost pushing back for 10-15 seconds of mayhem.
Off throttle surge = x ammount of boost in a given volume leaking back through the compressor, obviously diminishing pressure quickly over time, thus also force. You thought you were being smart with your pedanticism over the term "force", you have failed.

Also, explain to my why metal which is already hot "probably" won't have it's temperature affected by friction. I thought you did mechanical engineering???