Apr recirculation valve or Forge splitter BOV?

[noone]

Yes, I've read all those threads and the manufacturers documentation, thanks.

On the exit point of the unit you can see a cone shaped section with 3 slits. I believe altering (removing or filling in) these slits or blades would reduce the venting sound.The 3 blades act like a whistle or recorder, this is likely where the noise is created from. Make sense?

[Blitzen]

On the exit point of the unit you can see a cone shaped section with 3 slits. I believe altering (removing or filling in) these slits or blades would reduce the venting sound.The 3 blades act like a whistle or recorder, this is likely where the noise is created from. Make sense?

This is called a Venturi. This (in theory), speeds up the air coming out of the BOV. Anyway, I have this removed on mine, but still have it venting to atmosphere. It has made no difference to the sound being vented from the BOV.
I removed the Venturi so at a glance, it just looks like a DV, and not a BOV to the police if they want to have a poke around(I am looking at buying a Forge 007P DV for a stock looking one that won't bleed the extra boost of a tuned Polo).
I think it would be a lost cause and a waste of time to fill these small slits in the Venturi. The venting sound of the Forge BOV isn't that loud anyway. If you want a BOV, but want to reduce the sound from it, why not just get a Forge DV instead like this...

http://www.forgemotorsport.com/conte...oduct=FMCL007P

[noone]

Thanks mate, very helpfull.

So sounds like the Venturi makes it a bit louder, glad to hear you can leave it looking stock(ish).

As I have not heard either, its hard to know, guess i'm after something cool without the dirty looks.

If you go down the DV parth, will you keep the 2 port? I could help subsidize the new part

Do you expect the power difference to be noticeable between the 2?

[Blitzen]

Do you expect the power difference to be noticeable between the 2?

No, there would be no power difference between the Forge splitter BOV and the Forge closed loop DV.
The only reason I have my BOV on atm is that the stock DV cannot hold the extra boost of a tuned Polo GTI, and the boost bleeds past the DV and back to the intake side of the turbo.
An after market BOV/DV holds the boost better. If you Polo hasn't been tuned, there is really no need to change the DV.

[Chrisuk-polo]

i had the splitter and all i can say is its crap! I messed around for ages trying to set it up etc ! got teh 007p now much better! just get a cone filter and a chip and you will hear a nice whoosh! dont go full blow off as it goes tits up!

[noone]

Which one did you use Chrisuk? The Forge or the Other one?

[Petrina Polo]

I have the APR V1 Diverter Valve. Works a treat. with a pod setup you can hear the Pssshhhhh!!..

But any quality valve will do the trick, as long as it holds the boost thats what matters..

APR Diverter Valve is not cheap but does it offer anything over the Forge valve which is a fair bit cheaper??

I dont think a duel port valve will effect spooling.. its still releasing the pressure and not slowing up the turbo..

A plumb back bov is limited in its effectiveness as it goes back into the intake before the turbo but most of pressure is lost through air cleaner element so there is nothing really to help the turbo move.

[Blitzen]

i had the splitter and all i can say is its crap! I messed around for ages trying to set it up etc ! got teh 007p now much better! just get a cone filter and a chip and you will hear a nice whoosh! dont go full blow off as it goes tits up!

I have found the Forge BOV to work quite well...I have had it for 14 months now, and have lubed it once(takes about 15min to do). You are right it that it takes some amount of time to find the sweet spot, but I felt I have found it (36 clicks from the tightest setting). I am however looking at getting a Forge 007P for insurance and roadworthy reasons (if I was to have an accident, and the BOV was found, there is cause there to deny the insurance as a BOV dose make a car unroadworthy...And this isn't just for the sound issue, even though the sound from the Forge BOV isn't that loud(well under the 90db legal limit)...Look it up people...).
The 007P also looks very stock, and this is also what I am looking for.

1) I dont think a duel port valve will effect spooling.. its still releasing the pressure and not slowing up the turbo..

2) A) A plumb back bov is limited in its effectiveness as it goes back into the intake before the turbo but most of pressure is lost through air cleaner element...
B) ...so there is nothing really to help the turbo move.

1) True...

2) Um... What???
A)The MAF(Mass Air Flow) sensor detects that certain amount of air returned to the intake side of the turbo by the DV, and accounts for this in the on the fly tuning of the car. If a certain amount of air is not detected, the ecu will sence that something is not right, and adjust the air/fuel mixture accordingly. If this cannot be done properly, the ECU can/will throw a hissy fit and put the car into limp mode.
B) You have to remember that so long as the engine is running, the turbo is spinning. The movement of the exhaust gas and heat causes the Impeller blades to spin...This in turn is connected by a shaft to a Compressor/Turbine. This compressor is drawing air through the intake to the turbo. This air is then compressed and pushed through the intercooler to the throttle body and to the combustion chamber. It is nearly impossible for air to be lost back through the air intake when the engine is running.

[noone]

yeah, I thought one of the benefits to the plumback was to reduce the spool time as the pressure was better maintained (thus the potentially increased lag in a Full BOV).

[Bubu]

yeah, I thought one of the benefits to the plumback was to reduce the spool time as the pressure was better maintained (thus the potentially increased lag in a Full BOV).

That is one theory, I dont know if it has been proven or not. What I have noticed is that most tuners use full atmo BOV's. Sure some do it just for the sound but there are plenty out there are more interested in performance than the sound.

I think you will find that most plumbacks are made that way for pollution reasons and noise suppression.