Off Boost Compressor Surge

[titian]

to sum up bov positioning.

Setup Std:- Early setup (TMIC water/air) was blow off hot with return to turbo inlet. Reason:- free flow during throttle off and air flow ceases through intercooler.(Only the air required by the engine is cooled)

Setup Std:- later models (TMIC air/air) Blow off cold to return on turbo inlet. Reason:- full flow through intercooler during throttle off.

Both of the above return after the AFM. Further:- both reduce compressor surge issues.

Boy racer setup:- Blow to atmosphere, Either cold side or hot side. Hot side is best (why blow out cooled air?)

Either way if fitted you should/must retune to get the best result.

Any blow off system must allow freeflow through the turbo, otherwise surge (stall) will occur.

Relieving the hot side to the cold side or vise versa will not work. You need a pressure drop across the valve for correct operation. (Across the turbo is the only way)

Usually the BOV is open under cruise vacuum to allow excess turbo supplied air to either return or vent.

The danger of the atmospheric vented, open BOV are that:- On occasions of some throttle positions in combination with load/Rpm there is a chance of a vacuum occuring at the open BOV exit. This will then suck un filtered air into the intake manifold. :\'(

Further:- As pointed out below. Bov can be removed entirely!..Correct tune is a must to prevent surge issues. ;D

[vorigan]

There\'s nothing like beating a topic to death over something that\'s so obvious to start with as for needing a blow valve?

Not true but ive covered that enough

To sum it up....easy do whatever you please its your car and your paying the bills

[titian]

 vorigan said:

There\'s nothing like beating a topic to death over something that\'s so obvious to start with as for needing a blow valve?

Not true but ive covered that enough

To sum it up....easy do whatever you please its your car and your paying the bills

OOOps . Have to agree :) But i did not state:- Bov can be removed completly. Tuning required....Of course

[vorigan]

 titian']

[quote name='vorigan said:

There\'s nothing like beating a topic to death over something that\'s so obvious to start with as for needing a blow valve?

Not true but ive covered that enough

To sum it up....easy do whatever you please its your car and your paying the bills

/quote]

OOOps . Have to agree :) But i did not state:- Bov can be removed completly. Tuning required....Of course

ah no tad more to it than a tune sorry

sorry but ive really had enough of explaining things over and over and im not go to battle the internet warriors they know why to much for my liking........NOT

[titian]

Tuning:- My definition;_ Matching,balancing to achieve the highest achievable powers along with maximum reiability. ;D

After all balance is everything. This often requires serious thought,alteration and calculation.

There is more to tuning than a bloody dyno setup ;) esp without a Bov!

Mr V ...I believe we \'see\' the same? If you get my drift.

[vorigan]

 titian said:

Tuning:- My definition;_ Matching,balancing to achieve the highest achievable powers along with maximum reiability. ;D

After all balance is everything. This often requires serious thought,alteration and calculation.

There is more to tuning than a bloody dyno setup ;) esp without a Bov!

Mr V ...I believe we \'see\' the same? If you get my drift.

i hate to ask but balance what? the turbo?

everyone is balanced the same regardless of setup and turbo sizing again has nothing to do with it and ive said as much as i want to on the subject its getting boring

[titian]

 vorigan']

[quote name='titian said:

Tuning:- My definition;_ Matching,balancing to achieve the highest achievable powers along with maximum reiability. ;D

After all balance is everything. This often requires serious thought,alteration and calculation.

There is more to tuning than a bloody dyno setup ;) esp without a Bov!

Mr V ...I believe we \'see\' the same? If you get my drift.

/quote]

i hate to ask but balance what? the turbo?

everyone is balanced the same regardless of setup and turbo sizing again has nothing to do with it and ive said as much as i want to on the subject its getting boring

If i said your design of Bov is balanced. Where as many others are not. This should give you my understanding of balance.

There is far more to "balance" than dynamic and rotational..A?

Its just that most of the peeps on here do not understand the basics...Again i understand your frustrations.

Tune and balance is the only way to get the best result.

However tuning and balancing are not the same as tune and balance.(Mr V and those with IQ wil understand)

[94 Leone]

Elementary dear watson, Vorigan seems to dislike this thread with each post, basically just use a stock bov an re-circ it. no problems.

[vorigan]

 titian']

[quote name='titian said:

Tuning:- My definition;_ Matching,balancing to achieve the highest achievable powers along with maximum reiability. ;D

After all balance is everything. This often requires serious thought,alteration and calculation.

There is more to tuning than a bloody dyno setup ;) esp without a Bov!

Mr V ...I believe we \'see\' the same? If you get my drift.

/quote]

i hate to ask but balance what? the turbo?

everyone is balanced the same regardless of setup and turbo sizing again has nothing to do with it and ive said as much as i want to on the subject its getting boring

If i said your design of Bov is balanced. Where as many others are not. This should give you my understanding of balance.

There is far more to "balance" than dynamic and rotational..A?

Its just that most of the peeps on here do not understand the basics...Again i understand your frustrations.

Tune and balance is the only way to get the best result.

However tuning and balancing are not the same as tune and balance.(Mr V and those with IQ wil understand)

You been drinking or what, i never said any b/v is balanced that has nothing to do with the price of fish

The only way to get it right is do it right the first bloody time something the OEM did when they first made the car!

Does no one understand this part, had stock b/v car ran great no issues/put gay aftermarket b/v on it cars runs crap surges stalls in general a pain in the butt, gez i wonder what to do.

Now instead of being a "speacial" person either keep drinking or keep to the point in hand you seem to think you have a higher IQ than the rest solve the issue and shows hows its done DESIGN is the issue go forth and make one that queers all the issues people have bare in mind LTSA want to ban then at some point for emission purposes but im sure with your IQ you already knew that :

No dear 94 leone if you read from the start of the thread all the issues people have are with using aftermarket b/v or you didnt do that either

[94 Leone]

No, I said their problems will go away, once they re-circ stock bov, sorry for the confusion lol. Enjoy your new years.

[vorigan]

 94 Leone said:

No, I said their problems will go away, once they re-circ stock bov, sorry for the confusion lol. Enjoy your new years.

You said i "disliked" this thread ive been trying to point and provide proof to the design issues after doing this crap for over 30 years to why your wasting money on a aftermarket b/v but you would have known that if you read the thread from the start.

Once the LTSA regs kick in NO ONE can vent to atmosphere unless the car was designed that way from the factory and all the time and money people have put into hearing psssssssssssssst is wasted and to become illegal,end of issues

[94 Leone]

Yeah, sorry, should have worded it better "dislike the arrogance within the thread and the wider community about the use of crappy a/m B/V\'s?"

The LTSA standards are gonna kick a lot of people in the pants, but doesn\'t bother me: I run stock b/V

[vorigan]

Aftermarket b/v is going to the least of everyone\'s issues if LTSA adopt all of what other countries ad-hear to your going to need a cert to approve a cert its going to get that a.n.a.l, sorry 94 Leone its a forum she-height happens

[94 Leone]

It\'s alright, I understand frustration, maybe not thirty years of it but, I know it well lol. If they have it their way, you\'ll need a cert to just change your tyres or replace brake pads...

[vorigan]

 94 Leone said:

It\'s alright, I understand frustration, maybe not thirty years of it but, I know it well lol. If they have it their way, you\'ll need a cert to just change your tyres or replace brake pads...

in some parts of oz you need a cert to change stock wheels to another wheel of the same size! and changing air filters to a pod is a big no no we have it easy here....for now

[vorigan]

WTF? Did not ask to be set upon!! GOT THAT! ??? ??? ???

I am actually agreeing with you Design,tune, balance requires serious calculation.

Altering anything on the induction side requires more than a bloody screwdriver. As most of the wallys here do!

If we were sat in a pub having this discussion im sure that we would agree on this. Behind the keyboard requires double reading of others statements BEFORE one reacts to supposed provocation! :o

i stand corrected having a bad day my apologies unfortunately around this place you have to be on your back foot so i tend to shoot first then see whats left.

to be honest this topic goes on and on and on and on etc etc etc and they still dont get it guess theres no helping some, not meaning you ill buy you beer one day...but i dont drink but you can have your pick

[loner]

so... what exactly is the conclusion here? aftermarket BOVs are good and factory are shit... right? Better get on the trademe ASAP.

[titian]

 loner said:

so... what exactly is the conclusion here? aftermarket BOVs are good and factory are s***... right? Better get on the trademe ASAP.

quite the opposite. duh ???

Most but not all after market BOV are nonsense. And as stated unless they are full return they will soon be outlawed on subaru by authorities. :)

Atmospheric ones are ridiculous as anyway. And with out re tunig the engine it will only cause issues....I\'m sure this is where this post started >

Mr V... Looking forward to a meet one day I\'m sure there will be knowledge transfer both ways.. Cheers!

[loner]

 titian']

[quote name='loner said:

so... what exactly is the conclusion here? aftermarket BOVs are good and factory are s***... right? Better get on the trademe ASAP.

/quote]

quite the opposite. duh ???

Most but not all after market BOV are nonsense. And as stated unless they are full return they will soon be outlawed on subaru by authorities. :)

Atmospheric ones are ridiculous as anyway. And with out re tunig the engine it will only cause issues....I\'m sure this is where this post started >

ok sorry... so venting BOVs are the best, and standard ones are soon to be illegal... luckily I have found an awesome one on trademe... can\'t wait for that psssht psssht!

[vorigan]

 titian']

[quote name='loner said:

so... what exactly is the conclusion here? aftermarket BOVs are good and factory are s***... right? Better get on the trademe ASAP.

/quote]

quite the opposite. duh ???

Most but not all after market BOV are nonsense. And as stated unless they are full return they will soon be outlawed on subaru by authorities. :)

Atmospheric ones are ridiculous as anyway. And with out re tunig the engine it will only cause issues....I\'m sure this is where this post started >

Mr V... Looking forward to a meet one day I\'m sure there will be knowledge transfer both ways.. Cheers!

+1 someone sticky this reply under "why sub make the best b/v from factory" then lock this thread