To Bov Or Not To Bov

[thewelsho]

  mctwistuk said:

Thanks for the words of wisdom ...

Indeed they are; another knowledge bite to file away.

Since I got my car mapped (still on standard recirc) I can hear PSSSSSHT during gear changes at high revs. It's not loud mind, but definately noticable. Why has it started doing this, when it didn't do it before?

Edited February 11, 2008 by TheWelsho

[colin_ross]

Vta's are nasty things in MY opinion. Subaru designed a perfectly fine dump valve and for perfomace and reliabilty that's what I would stick with. If you're significantly upping your boost then change to a forge recirc so you can use a stronger spring but that's it.

Having said all that I have a vta on my car but because of my cars spec it is the best solution. If I could fit a recurc I would.

And another thing, for the people who say they can hear their standard one now they've fitted a induction kit.... no. You can't. What you can hear is compressor stall.

[scoob fae ork]

Hi guys sorry to butt in on this post just want to ask tho i have a 04 STI with an HKS BOV i had the car mapped last year with the BOV fitted is there any benifet for me to put the standard one back on or is it not possible now after the car being mapped ???

[thewelsho]

  Playsatan2 said:

And another thing, for the people who say they can hear their standard one now they've fitted a induction kit.... no. You can't. What you can hear is compressor stall.

Colin,

I don't have an induction kit fitted, so what am I hearing then?

[colin_ross]

When you're on boost your intercooler is full of presurised air and this will find it any way out it can. If you're on the gas it will be through the throttle body and into the engine. Then you lift off which closes the butterfly in the throttle body and at the same time stops the turbo pressure. The presurised air now has to find somewhere else to go and that is back through the turbo, this is whar creates the chuffing noise that you can hear.

In standard spec the airbox does a good job of muffling this sound, even better if you leave the resonator on. Take these off and it's very noticable.

[fai17]

he he he....

mod mod mod....it's that all you think of?

[mctwistuk]

  fai 17 said:

he he he....

mod mod mod....it's that all you think of?

i wonder who it was that got my mind trained to that sort of thinking lol??????????????

[Carson]

The best sounding bov afer the normal cold air induction is greddy type s !

am sick of the hks one

[thewelsho]

  fai 17 said:

he he he....

mod mod mod....it's that all you think of?

Peter, still not heard from Duncan. I called him and he never picked up, I'll try again though.

[GaryD]

Chris, a will have my HKS BOV for sale in the next few weeks if you are interested?

[mctwistuk]

  GaryD said:

Chris, a will have my HKS BOV for sale in the next few weeks if you are interested?

thanks for the offer Gary but am going to go the CAI route i think when i get remap.

How come your selling it?

[rallye6]

BELOW IS THE RESPONSE FROM TURBOSMART, WHEN I READ ALL THE POSTS I E MAILED THEM FOR THOUGHTS.

From: Andy Taylor [mailto:andy@aet-turbos.co.uk]

Sent: 07 February 2007 16:02

To: Brian Smith

Cc: Andy Nichols; Grant Parker; Matthew Leedale

Subject: RE: 03 newage subaru impreza wrx TURBOSMART DUMP VALVE

Dear Brian

Thank you for your email and your concerns about running an atmospheric BOV on your vehicle. I have passed on your concerns to T/Smart in Aus and below is there thoughts:

“It all sounds great what he has written, but the "fuel cut on over run" or "Decel fuel cut" or what ever else you want to call it will shut the injectors off when you lift of the throttle, this sorts everything out. What he has written "might" happen for the shortest time, but in my opinion will cause no real world measurable effect.

The back firing etc in the exhaust happens as the revs drop down towards idle speed and the ECU will start fuelling again to allow for a smooth transition back to idle and not to cause stalling.”

Might I add in all the years we have sold this product we have never had any feedback from anyone advising us of this problem and Subaru is our biggest market.

Cheers, Andy Taylor

--------------------------------------------------------------------------------

From: Brian Smith

Sent: 05 February 2007 10:34

To:

Subject: 03 newage subaru impreza wrx

Hi hope you can help, I have just fitted a v port turbosmart dump valve to my 03 wrx impreza. I am very pleased with it and love the sound, but on our sidc website one of our members said they can be detrimental to the engine can you elevate my fears. Hear is his article below

Thanks Brian smith

Scotland united kingdom. My email address is

The Impreza runs off the MAF sensor when in open loop fuelling, when you are giving it some stick. The Mass Air Flow will meter the amount af air being drawn into the engine and inject the corresponding amount of fuel amount to achieve a rich enough Air to Fuel Ratio when on boost/load conditions.

When you release the throttle, to change gear or slow, on a std recirc dump valve, the pressurized air will be dumped back into the inlet tract between the MAF and turbo inlet. When the throttle is closed on gear change on slow down the ecu will inject a corresponding amount of fuel to achieve a satisfactory AFR to compensate for the extra volume being drawn in. When you fit a Vent to Atmos dump valve, the pressurized air will be released to the atmosphere when the throttle is closed but the ECU will still dump extra fuel in trying to achieve a satisfactory AFR. The ECU thinks there is an extra volume of air being drawn in the engine and will inject the right amount of fuel to compensate, this metered volume of air has now been dumped into the atmosphere instead of the inlet tract. A std ECU has no way of knowing that the Air volume that has passed the MAF , which has been metered for and compensated for accordingly has been released outside the inlet tract instead of being drawn into the engine. This will in turn make the AFR be very RICH due to the air part of the AFR being expelled through a valve the ECU has no knowledge of

The extra fuel that is being drawn into the engine, minus the volume of air the ECU was expecting will do 1 of 2 things.

1. It will explode when the rich mixture hits the piston crown, giving a flash of lift off DET. At full boost and at the point of ignition the temp of the exhaust gases can average 800 and hit 900 - 1000 degrees centigrade after a spirited drive, the crowns of the piston at the point of ignition can be as high as 700 - 800c. This temperature is more than enough to ignite the fuel mixture before the spark can do the job and be a cause of lift off det and lift off dat can be damaging as DET under load

2. It will not explode but as the mixture has ignited by the spark from the plugs and the flame front travels across the piston, by the time the exhaust valve has opened on the exhaust stoke the overly rich mixture has not fully burnt by the inappropriate ignition level . Sometimes the rich fuel vapors not burnt from the time allotted in the combustion process will pop in the exhaust housing of the turbo when the gases exit the combustion chamber. Sometimes these pops will be sufficient to produce a a flame strong enough to travel the length of the exhaust syatem resulting a nice wee flame for everyone to go aaaaaawwwwww at but every time you do not get a flame the unburt fuel will be lingering somewhere in the exhaust tract, headers, hot side of turbo or even the chamber walls

The atomized fuel droplets that cling to the wall in the combustion chamber will clean the oil off the walls of the piston bore every time the overly rich Air/Fuel mixture is being drawn into cylinders. The unburnt fuel mixture will get past the compression and oil control rings due to petrol mixture being a lot finer than oil and the excess mixture that has not been ignited will stick to the cylinder walls due to the condensation effect of the AFR that is being pumped into the engine every time the inlet valves open, mixture being around 10-30c and the walls of the cylinder being around 200 - 400c, the retaining temp from the previous combustion cycle which at 6000 rpm (avg gearchange rpm) would have happened millisecs beforehand . This fine petrol mixture will be transferred to the oil in the sump, getting past the oil control rings as atomized fuel is a lot finer than thick engine oil. The classics lubricated the piston bores and under the piston crown with the end of the crank scooping oil up and throwing the oil up the bores, apart from STI RA's which had under crown oil cooling jets to cool the underside of the piston. The oil that has been thrown up by the crank to lubricate the bore is prevented from entering the combustion chamber by the rings on the piston but atomized fuel can easily get past these rings assisted by the pressurized gases in the combustion chamber above helping it on its way and once past the rings the tiny droplets of fuel will soon find its way to the sump abley assisted by the laws of gravity. Over time these droplets of fuel will be sufficient to start to thin the oil down to a dangerous level and increase the chance of picking up a big end bearing

My advice for the peeps running a Vent to Atmosphere is to, apart from dump them in the bin, is to increase the regularity of oil changes.

Hope this helps

[wilky]

Of course he is going to say that, he makes them ffs.

If you want one. buy the fecker and fit it. Happy borewashing.

I have seen borewash three times on cars I have owned. Once on a 1380 Mini I owned when I fitted a wrongly jetted webber 45

Once on the Millenium falcon when I got it wrong whilst self mapping on a link ecu I had.

And once on Andyjdmstis car before it was the fatboy when he fitted a turbosmart BOV. All symptoms were identical, sudden increase in oil volume due to dilution with fuel making it a poor lubricant.

The mini was cured by rejetting

The falcon was cured by ajusting the fuel at certain point on a certain row I had buggered up

Andys car by re fitting the standard dump valve.

Its not a good idea In my opinion.

Mind you they said that about Iraq and did it stop anybody? No.

Callum W

Edited February 11, 2008 by Wilky

[the squiggle]

  rallye 6 said:

BELOW IS THE RESPONSE FROM TURBOSMART, WHEN I READ ALL THE POSTS I E MAILED THEM FOR THOUGHTS.

From: Andy Taylor [mailto:andy@aet-turbos.co.uk]

Sent: 07 February 2007 16:02

To: Brian Smith

Cc: Andy Nichols; Grant Parker; Matthew Leedale

Subject: RE: 03 newage subaru impreza wrx TURBOSMART DUMP VALVE

Dear Brian

Thank you for your email and your concerns about running an atmospheric BOV on your vehicle. I have passed on your concerns to T/Smart in Aus and below is there thoughts:

“It all sounds great what he has written, but the "fuel cut on over run" or "Decel fuel cut" or what ever else you want to call it will shut the injectors off when you lift of the throttle, this sorts everything out. What he has written "might" happen for the shortest time, but in my opinion will cause no real world measurable effect.

The back firing etc in the exhaust happens as the revs drop down towards idle speed and the ECU will start fuelling again to allow for a smooth transition back to idle and not to cause stalling.”

Might I add in all the years we have sold this product we have never had any feedback from anyone advising us of this problem and Subaru is our biggest market.

Cheers, Andy Taylor

--------------------------------------------------------------------------------

From: Brian Smith

Sent: 05 February 2007 10:34

To:

Subject: 03 newage subaru impreza wrx

Hi hope you can help, I have just fitted a v port turbosmart dump valve to my 03 wrx impreza. I am very pleased with it and love the sound, but on our sidc website one of our members said they can be detrimental to the engine can you elevate my fears. Hear is his article below

Thanks Brian smith

Scotland united kingdom. My email address is

The Impreza runs off the MAF sensor when in open loop fuelling, when you are giving it some stick. The Mass Air Flow will meter the amount af air being drawn into the engine and inject the corresponding amount of fuel amount to achieve a rich enough Air to Fuel Ratio when on boost/load conditions.

When you release the throttle, to change gear or slow, on a std recirc dump valve, the pressurized air will be dumped back into the inlet tract between the MAF and turbo inlet. When the throttle is closed on gear change on slow down the ecu will inject a corresponding amount of fuel to achieve a satisfactory AFR to compensate for the extra volume being drawn in. When you fit a Vent to Atmos dump valve, the pressurized air will be released to the atmosphere when the throttle is closed but the ECU will still dump extra fuel in trying to achieve a satisfactory AFR. The ECU thinks there is an extra volume of air being drawn in the engine and will inject the right amount of fuel to compensate, this metered volume of air has now been dumped into the atmosphere instead of the inlet tract. A std ECU has no way of knowing that the Air volume that has passed the MAF , which has been metered for and compensated for accordingly has been released outside the inlet tract instead of being drawn into the engine. This will in turn make the AFR be very RICH due to the air part of the AFR being expelled through a valve the ECU has no knowledge of

The extra fuel that is being drawn into the engine, minus the volume of air the ECU was expecting will do 1 of 2 things.

1. It will explode when the rich mixture hits the piston crown, giving a flash of lift off DET. At full boost and at the point of ignition the temp of the exhaust gases can average 800 and hit 900 - 1000 degrees centigrade after a spirited drive, the crowns of the piston at the point of ignition can be as high as 700 - 800c. This temperature is more than enough to ignite the fuel mixture before the spark can do the job and be a cause of lift off det and lift off dat can be damaging as DET under load

2. It will not explode but as the mixture has ignited by the spark from the plugs and the flame front travels across the piston, by the time the exhaust valve has opened on the exhaust stoke the overly rich mixture has not fully burnt by the inappropriate ignition level . Sometimes the rich fuel vapors not burnt from the time allotted in the combustion process will pop in the exhaust housing of the turbo when the gases exit the combustion chamber. Sometimes these pops will be sufficient to produce a a flame strong enough to travel the length of the exhaust syatem resulting a nice wee flame for everyone to go aaaaaawwwwww at but every time you do not get a flame the unburt fuel will be lingering somewhere in the exhaust tract, headers, hot side of turbo or even the chamber walls

The atomized fuel droplets that cling to the wall in the combustion chamber will clean the oil off the walls of the piston bore every time the overly rich Air/Fuel mixture is being drawn into cylinders. The unburnt fuel mixture will get past the compression and oil control rings due to petrol mixture being a lot finer than oil and the excess mixture that has not been ignited will stick to the cylinder walls due to the condensation effect of the AFR that is being pumped into the engine every time the inlet valves open, mixture being around 10-30c and the walls of the cylinder being around 200 - 400c, the retaining temp from the previous combustion cycle which at 6000 rpm (avg gearchange rpm) would have happened millisecs beforehand . This fine petrol mixture will be transferred to the oil in the sump, getting past the oil control rings as atomized fuel is a lot finer than thick engine oil. The classics lubricated the piston bores and under the piston crown with the end of the crank scooping oil up and throwing the oil up the bores, apart from STI RA's which had under crown oil cooling jets to cool the underside of the piston. The oil that has been thrown up by the crank to lubricate the bore is prevented from entering the combustion chamber by the rings on the piston but atomized fuel can easily get past these rings assisted by the pressurized gases in the combustion chamber above helping it on its way and once past the rings the tiny droplets of fuel will soon find its way to the sump abley assisted by the laws of gravity. Over time these droplets of fuel will be sufficient to start to thin the oil down to a dangerous level and increase the chance of picking up a big end bearing

My advice for the peeps running a Vent to Atmosphere is to, apart from dump them in the bin, is to increase the regularity of oil changes.

Hope this helps

I was sitting there reading the reply to the the quoted email thinking that it sounded familer, should do it was me that wrote the words printed above and i stand by every last one of them. Nice to know my words are being discussed around the world

Got to agree with Wilky as you asked the wrong person if the product would damage the car

Lovin the parts where it says it "might" happen and "Sorts everything out". Wake up and smell the coffee mr bloody turbosmart, it does happen and no the ECU is not gonna "Sort everything out" like some kind of East End heavy

It is a fact that over time somehow fuel gets into the oil in the sump, predominantly on cars fitted with a VTA. So how does turbo bloody smart ass suggest this may happen. What other way is there apart from the way described above and short of opening the oil filler cap and proceeding to pour in 10 litres of Shells finest, an action in someone on day release from Carstairs would do. Are Turbo (bloddy buy our product and listen to our sales gumph as it was written by Goebells himself before the fall of the Reich in 45) Smart suggesting that fairies or leprachauns open the filler cap in the dead of night and proceed to fill the oil filler cap with fuel in a style a madman from Carstairs would be proud of.

So couple of questions for either the originator of the email to fire back to them or i will

1. How do TSmart suggest that the fuel gets in there?

2. Are they denying that borewash exists on an EJ series of engine?

..............................................

In fact scrap everything i wrote all those moons ago and go for it. If your lucky then the worst that will happen is some blind old Biddy will step out in front of you thinking you are the number 44 to the Drum. If you are unlucky then you are shelling out for a rebuild. You can take your chances all you please just to get the ppppssschchhhhhttt sound. For me std recirc does just fine

As Wilky also said

Happy Borewashing

[the squiggle]

plus

Would you go ask McDonalds if just living off thier products would do you any harm?

Of course McDonalds would say "our food is full of nutrition". Then we watch the movie "Supersize me" where mr Spurlock only eats McD's grub for a month.and nearly dies on his ass

Consider Wilky's and mine ramblings to be the Micheal Moore of the VTA Dumpvalve

[fai17]

Most amusing but very factual...

VTA...on remap cars only please

[mctwistuk]

When i started this thread i didn't think it would turn into what it has done. The amount of knowledge that ther eis on the forums is astounding and is why i asked the question. As Grant rightly puts, if you ask a company if there is a problem with their product of course they are going to say no. that is why this forum is so popular with Scooby owners. Being a novice (i mean real novice) on scoobs all help and guidance and can get from the wizards on here is invaluable. These people have been there, done that and bought the t-shirt several times over and have learned from their mistakes. It may have cost them a wee bit of money or quite a bit of money but they have learned what to do and what not to do and want to makes sure that they give advice to others to prevent it form happening to them.

I thank all the masters in here that spread their vast amount of knowledge in here as without them my car would probaly have blown up several times over by now.

[fai17]

  mctwistuk said:

...blown up several times over by now.

What me!!! quilty your hounor

[ur.a.bus]

there is a fitting kit for the HKS sqv that recirc's the air back to air box rather than VTA.

would this stop borewash? i might get the kit until i get remap after reading all this

[scoob fae ork]

So is my car safe with having a re map with a VTA BOV

[wilky]

  Scoob Fae Ork said:

So is my car safe with having a re map with a VTA BOV

You have Gumballs old car yes?

That car had no issues with the dump valve it was sold to you wearing.

I remember him checking.

Callum W

[wilky]

  mctwistuk said:

I thank all the masters in here that spread their vast amount of knowledge in here as without them my car would probaly have blown up several times over by now.

I am by no means a master. There are many people who are more technically gifted and know far more than me. I simply talk from experience or from having observed. If I dont know or I get it wrong Ill always try and find out from someone who does.

[scoob fae ork]

  Wilky said:

You have Gumballs old car yes?

That car had no issues with the dump valve it was sold to you wearing.

I remember him checking.

Callum W

No sorry thats my mate that has the Gumball Scoob i have a black 2004 STI with a cold air induction kit turbo back de cat ss exhaust and an Andy F Re-Map could the VTA BOV still damage the car ????

[wilky]

  Scoob Fae Ork said:

No sorry thats my mate that has the Gumball Scoob i have a black 2004 STI with a cold air induction kit turbo back de cat ss exhaust and an Andy F Re-Map could the VTA BOV still damage the car ????

If it was mapped with the BOV fitted then there shouldnt be any issues. If you have fitted it after the remap then its worth checking.

[scoob fae ork]

  Wilky said:

If it was mapped with the BOV fitted then there shouldnt be any issues. If you have fitted it after the remap then its worth checking.

Yeah it was mapped with the bov on thanks for your help.

Donald