Turbo feels underpowered after installing BOV

[Readonly]

... wtf....

 

i dun wan my car to die..

 

you can fix back the original bpv if you want to.

BPV is still best for low pressured turbo cars.

[Aeromania]

really? turbo master of the world?

i have seen his nick around but i didnt think he had that title.

 

Last time any thread about turbo he cfm "Chap-zi-kar".

 

And he also start a lot silly silly threads about turbo. Quite annoying actually.

 

and since he's so hungry for it then just give it to him lor hahahaha.

 

 

[Aeromania]

... wtf....

 

i dun wan my car to die..

 

Upgrade turbo

 

Open pod intake

 

Tune ECU

 

Boost controller

 

Straight pipe

 

Decat

 

Upgrade Intercooler

[thumbsup] [thumbsup]

 

[Babysaint]

yeah.. think i will just put the bpv back.. but can some1 tell me how to know if the turbo died?

[Aeromania]

yeah.. think i will just put the bpv back.. but can some1 tell me how to know if the turbo died?

 

when u rev until engine explode still no boost lor.

 

If not wrong legacy gt 2.5k rpm turbo will kick in already.

 

If cannot feel then hor hor... ...go garage check lor.

[Babysaint]

waa... i really dunno lehh... just seems different.. and i got quite a few qns to ask.. like low pressure turbo car is like mine rite?

[Readonly]

Last time any thread about turbo he cfm "Chap-zi-kar".

 

And he also start a lot silly silly threads about turbo. Quite annoying actually.

 

and since he's so hungry for it then just give it to him lor hahahaha.

 

ic, the gt4 ST205? requires alot of work on the 3S-GTE.

weakness is its compression ratio and its thin walls engine block.

 

other than that a decent turbo ar :)

 

but a pity with COE, we are losing alot of our car history in singapore.

[Readonly]

waa... i really dunno lehh... just seems different.. and i got quite a few qns to ask.. like low pressure turbo car is like mine rite?

 

is yours a IHI VF46 turbo?

[Aeromania]

waa... i really dunno lehh... just seems different.. and i got quite a few qns to ask.. like low pressure turbo car is like mine rite?

 

dun think legacy GT is low pressure turbo (LPT) leh.

 

ur GT is 2.0L or 2.5L model?

[Aeromania]

ic, the gt4 ST205? requires alot of work on the 3S-GTE.

weakness is its compression ratio and its thin walls engine block.

 

other than that a decent turbo ar :)

 

but a pity with COE, we are losing alot of our car history in singapore.

 

I also dunnoe what kinda GT4 he driving la. I also nv drive turbo car b4. Only turbo pickup.

 

Anyway most singaporean also backside itchy, change car every few years. not much will keep for life.

 

and anyway, it takes a certain degree of dictatorship in order for COE to be a success also.

[Melvyn]

Not an expert. Just knowledge sharing.. So here goes a wall of text..

 

BOV is a device to vent out compressor surge. As some may know, turbocharging is how a car uses exhaust gases to help the engine to draw in more air to feed the 4 stroke internal combustion process. When you lift off the accelerator, the throttle plate closes, however, the high velocity compressed air does not shut off like a tap and when it hits the said closed throttle plate, it has to go somewhere right? in the absence of a BOV, the air rebounds back along the charge pipes and creates a pressure spike between the throttle plate and the snail. This in turn creates a large reverse force on the compressor wheel shaft. This places tremendous force on both the axle shaft and thrust bearing surfaces within the TC unit.

Imagine your fan spinning clockwise to circulate the ambient air behind the blades out towards you (TC spooling air to the 4 stroke process). Now you suddenly direct an equally strong gust of air to the fan (throttle plate closes and the "backdraft" occurs) and the fan blades still want to move clockwise yet the force of the said strong gust of wind wants it to go anti clockwise (reverse force).

So the BOV is a vent to release the compressed air so that the TC unit do not experience the pressure spike caused by the shut throttle plate.

 

Now on the TS problem..

When you buy a BOV, you should know one most important thing and that is if your ride is using MAF fuel monitoring system. This in turn will decide whether you should buy one of two common BOV designs. First is the vent to atmosphere system (open system) or the vent to induction system (closed system). TS should find out if your ride uses MAF sensors. Your car, your homework

MAF equipped cars should use BOVs that redirect the compressed air back into the compressor inlet of the turbo. Why? Simply because if the open system type is used, the compressed air vents to the atmosphere and ECU receives a signal from the MAF sensor that triggers a fuel-rich condition whenever valve opens, i.e., during shifts. What happens? Anything from engine hesitation to spark fouling to stalling.

 

Then we move on to buying consideration, whether you want a piston type or diaphragm type. But it's another story for another time if there's a need. Also there's a need to see if you want adjustibility (is there such a word? Haha) through spring or pre-load for different boost pressures. Lastly, there's a need to also see the material used. But same thing, anoher long story for another occassion I suppose.

 

Now for TS BOV - the GReddy Type RS.. It's a universal application that can be fitted to most rides. Made of aluminium (which most BOVs are made of anyway), it uses a proprietry oil and rolled hat design which is a vented system although I'm not sure if there's a recirculation system (You will have to ask the person/garage/shop who sold you). Uses a two bolt flange type with standard dual springs.

 

So now what TS may do:

 

1) Check if your ride is MAF equipped then see if you should be using open or closed BOV as I mentioned above.

 

2) If the BOV is the correct match.. Check the spring stiffness adjustment screw see if its matched to your ride's boost. I assume no heavy mods so boost is mild. In the first place, the reason why Subaru did not fit a nice BOV was that your ride did not need it but since you bought it might as well use it

 

3) Check if the BOV is suited for your ride's spec. Ideally, BOV should release just the surge pressure, not all of the boost. Too small and the surge is not released and causes flutter. Too big and all boost is released. Results in weak sound, poor performance and basically just wasting fuel as you try to step harder on the accelerator. IMHO, I feel this is what you're facing

 

Now, I have to say this, I'm in no way an authority on engine mechanics or Subarus as I had never owned one before and the closest I had was your rival car of sorts in a Mitsubishi VIII but I figured the general knowledge should be pretty close. Neither should you take what I say without doing your homework to verify my, or in fact anybody's random typing on the net and especially in this forum where anyone and everyone is an expert on cars. Best advice besides doing your research is to ask in a forum where same make and models congregate to get more accurate info.

Lastly, hope I helped and if not, at least provided some light reading to people

[Melvyn]

Oh.. And I dun know if you installed the BOV yourself but I made the mistake of not connecting the vacuum line behind the TB back then. So do make sure that the vacuum source is BEHIND the throttle body

[Good-Carbuyer]

I am puzzled. You bought car with turbocharger. So why install blow-off valve? I believe this is what you can get = non-turbocharged performance. Nothing wrong with car. No harm to car. Just enjoy yourself experimenting.

[Mona-vie]

Actually, BOV and BPV are the same thing. The purpose is simply to vent the excess air when you let off the accelerator. BOV vents it into the atmosphere. BPV vents it back to your intake (before the Turbo of course).

 

TS, what do you meant by loss of power? Does it happen when you are boosting or after you change gears and let go accelerator?

 

Cause if the BOV is not working properly, the valve will fail to open and the pressure will force the compressor blades to slow down (something like turbo stalling). Hence when you step on accelerator again, you will need some time to build up the boost. It will spoil the turbo in the long run though. Not a good thing.

 

If its causing you to accelerate slower when you are boosting, then the valve may be leaking. Air leaking thru it causing a loss of air pressure and hence lower boost.

 

Lastl, you do NOT need an aftermarket BOV for stock car. Its just a waste of money and it does not boost performance at all. Your stock BPV is more than sufficient to cater for the boost. Unless you mod your car and run something like 1.5 bars or more you don't need aftermarket BOV.

[Strudel-]

Actually, BOV and BPV are the same thing. The purpose is simply to vent the excess air when you let off the accelerator. BOV vents it into the atmosphere. BPV vents it back to your intake (before the Turbo of course).

 

TS, what do you meant by loss of power? Does it happen when you are boosting or after you change gears and let go accelerator?

 

Cause if the BOV is not working properly, the valve will fail to open and the pressure will force the compressor blades to slow down (something like turbo stalling). Hence when you step on accelerator again, you will need some time to build up the boost. It will spoil the turbo in the long run though. Not a good thing.

 

If its causing you to accelerate slower when you are boosting, then the valve may be leaking. Air leaking thru it causing a loss of air pressure and hence lower boost.

 

Lastl, you do NOT need an aftermarket BOV for stock car. Its just a waste of money and it does not boost performance at all. Your stock BPV is more than sufficient to cater for the boost. Unless you mod your car and run something like 1.5 bars or more you don't need aftermarket BOV.

 

You must understand 90% of the people that got after market gay BOV for the sound...

[Mcf777]

boobs over vagina hahahaha

 

 

Blow Off Valve la. u know when driving turbo car u open throttle turbo spool spool spool then when release throttle will "pewwwww" ahhhhh fyi that one not turbo sound that one is the sound of BOV release excess air.

 

 

UNDERSTOODED????

 

now then I understooded where the "pewwwwww" sound is coming from....LOL

All along i thot the sound is from the exhaust

[Melvyn]

Actually, BOV and BPV are the same thing. The purpose is simply to vent the excess air when you let off the accelerator. BOV vents it into the atmosphere. BPV vents it back to your intake (before the Turbo of course).

 

TS, what do you meant by loss of power? Does it happen when you are boosting or after you change gears and let go accelerator?

 

Cause if the BOV is not working properly, the valve will fail to open and the pressure will force the compressor blades to slow down (something like turbo stalling). Hence when you step on accelerator again, you will need some time to build up the boost. It will spoil the turbo in the long run though. Not a good thing.

 

If its causing you to accelerate slower when you are boosting, then the valve may be leaking. Air leaking thru it causing a loss of air pressure and hence lower boost.

 

Lastl, you do NOT need an aftermarket BOV for stock car. Its just a waste of money and it does not boost performance at all. Your stock BPV is more than sufficient to cater for the boost. Unless you mod your car and run something like 1.5 bars or more you don't need aftermarket BOV.

 

Hi, curious to know what BPV stands for? Is it what we term as CBV for compressor bypass valve?

Edited May 4, 2011 by Melvyn

[Rb26dett]

don't need to headache so much.

 

in order not to have your money wasted, just spend a little more and get a plumb back kit .YES greddy makes them too.

don't need to get technical here.just go back to the workshop , tell them you want a greddy plumb back kit.let

the workshop do the rest,thats their job.

 

oh ya though you wont hear so much of the sound anymore , BUT HEY ! when you open up your engine bay..there ..its still there..

 

on a sidenote...why a type RS..its kinda...gay...should've gotten the type R instead.no offence.

Edited May 5, 2011 by Rb26dett