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Chav time :) BOV questions


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#1 dnok

dnok
  • LocationElland West Yorkshire

Posted 19 July 2016 - 11:39 PM

So I got bored, removed the hose off of the recirc bpv, capped the hose to the turbo and left the bpv open turning it into a bov. I love the sound (of the car sneezing as far as my little lad is concerned lol) and ran it like that for a couple of days just to see if I got bored. If anything I loved it more and I must confess I like the looks it gets you lol.

Problem is the car ran like sh1t tbh. Soon after it I got the feeling it wasn't boosting as hard or as quick. This was confirmed today upon refitting the pipe to the bpv and noticing the difference straight away. With it in bov mode it also dipped the revs to near stall point a couple of times when say at a junction etc.

Anyway enough waffle. Is there a way to run a bov without any performance loss on the fozy? Is it something I could fit prior to getting remapped after I finish the power build and have it run properly?

I ran a few google searches and found many threads saying mapping will solve it but then found many many posts saying that they went back to the standard bpv and noticed a performance increase. Bugger.

So are those saying it can be sorted with a remap just kidding themselves and actually harming the performance of their cars?

As part of my build I'm contemplating running a cone filter behind the front fog opening using a maf adapter pipe and alloy pipework so as to retain the maf. I absolutely love the sound of scoobs running an all metal cone filter, they sound mental. I'm aware of the possibility of more dust particles entering my engine. I'm also aware they are the freest (spelling?) flowing filter so it's a trade off I guess. Basically I'd be running something like the Perrin pipe with a stainless steel filter.

With a cone filter and higher boost pressure how audible will the standard bpv be? Is it possible I'd still get quite an audible bov sound anyway with that setup and need not bother with and actual bov?

I know it's a bit of a chavy subject for some but to each their own. The sound has got me hooked lol. NOT prepared to sacrifice performance though!

Cheers guys

#2 brownpantsracing

brownpantsracing
  • LocationBucks

Posted 20 July 2016 - 07:59 AM

Changing to VTA bov shouldn't effect performance at all. Mine made the same power with standard and with the HKS SSQV fitted (which I now have for sale by the way). :)

 

They are not everyones cup of tea and get slated by most Subaru enthusiasts, but I loved it! haha.

 

I wouldn't run without a dump valve on the VF range of turbos as they don't last long.


2004 FSTI, Modified 2006 Impreza, 1963 VW beetle. All on the road for once! Woo hoo! :)


#3 dnok

dnok
  • LocationElland West Yorkshire

Posted 20 July 2016 - 08:03 AM

Changing to VTA bov shouldn't effect performance at all. Mine made the same power with standard and with the HKS SSQV fitted (which I now have for sale by the way). :)
 
They are not everyones cup of tea and get slated by most Subaru enthusiasts, but I loved it! haha.
 
I wouldn't run without a dump valve on the VF range of turbos as they don't last long.


Hi bud. Did you have yours in the rollers back to back then with standard bpv and then the hks?

#4 brownpantsracing

brownpantsracing
  • LocationBucks

Posted 20 July 2016 - 08:40 AM

Had the car on the rollers with the standard valve and the HKS but not back to back to compare. Also the car had undergone LOADS of upgrades by the time the HKS was fitted. All I can say is that there was no boost leak at all from either valve and both held boost very well indeed. The HKS holds itself shut under boost, it's quite a unique design. All other valves rely on the spring pressure against boost to hold shut, so depending on spring condition, age, strength they COULD leak.

 

Don't see how yours was loosing boost by un-plumbing the return and blocking it off though. Very odd indeed.

 

It may run differently as the Subaru fuel/air system dumps boost through the dump valve after the MAF sensor. In the standard system with recirculating valve it dumps the air back into the same system so the amount of air is still as it was measured. If you use a vent to air dump valve then you are dumping into free air and supplying less air than the MAF thinks you are. This has the knock on effect of over-fuelling the system (very slightly) and can make it run worse. It COULD lead to bore wash and block damage in theory, but this has never been proven yet.


2004 FSTI, Modified 2006 Impreza, 1963 VW beetle. All on the road for once! Woo hoo! :)


#5 dnok

dnok
  • LocationElland West Yorkshire

Posted 20 July 2016 - 10:15 AM

Well in the interest of clarity I can't 100% claim loss of boost pressure as I don't use my boost gauge I took it off. What I can say is though I drive the car every day most of the day an absolutely definitly noticed a lazier spool and less pull.
It seemed to bog down too.

I'm hugely tempted by a bov and yourself and others make compelling arguments for them being perfectly fine but I'm just not convinced. As you say the ECU has already calculated the air that you just dumped out of the system so logically that already tells me it had to have a negative impact on performance. Meh, damn it, I'm torn lol.

Anybody have any thoughts on bpv/bov delete? Can of worms time lol. Again it sounds spectacular but then again am I right in thinking it will have a similar effect on the system as a vta bov?

I'm doubly wounded now because after the snorkus delete I noticed quite an improvement in sound from the release of pressure but after running round vta style for a few days and then going back to the standard bpv setup I now don't notice the sound whatsoever :(

#6 brownpantsracing

brownpantsracing
  • LocationBucks

Posted 20 July 2016 - 10:33 AM

It was more likely the ECU retarding the timing due to the effect of the system changes. The ECU is a learning type and will fuel correct to pull fuel and timing etc where required to a point.

 

Don't do BOV delete on the VF turbo. What it will do is make a different fluttering noise (if you have a non-standard air filter system) that can sound nice. This is due to turbine stall and gasses being pushed the wrong way. It has been known to promote premature shaft wear and failure of the turbo. As already said, the VF turbos don't respond well to it but lots of other aftermarket units work much better with a DV delete.


2004 FSTI, Modified 2006 Impreza, 1963 VW beetle. All on the road for once! Woo hoo! :)


#7 Blastertrev

Blastertrev
  • LocationSunny Cumbria (NOT)

Posted 20 July 2016 - 10:36 AM

It may run differently as the Subaru fuel/air system dumps boost through the dump valve after the MAF sensor. In the standard system with recirculating valve it dumps the air back into the same system so the amount of air is still as it was measured. If you use a vent to air dump valve then you are dumping into free air and supplying less air than the MAF thinks you are. This has the knock on effect of over-fuelling the system (very slightly) and can make it run worse. It COULD lead to bore wash and block damage in theory, but this has never been proven yet.

It also has the potential to foul your plugs and your cat. if it's over-fuelling. The idea of the recirc. valve I've been told is that (as well as not confusing the ECU) it keeps more of the energy in the compressed air in the system slightly aiding spooling - if you think of the air whizzing round in a circle you can see how it helps keep the turbo spinning.


May the Foz be with you....


#8 Blastertrev

Blastertrev
  • LocationSunny Cumbria (NOT)

Posted 20 July 2016 - 10:36 AM

duplicate post


May the Foz be with you....


#9 brownpantsracing

brownpantsracing
  • LocationBucks

Posted 20 July 2016 - 10:47 AM

utf-8BSU1BRzAyNjMuanBn-2.jpg

 

This was my 2.5 Impreza running with an HKS SSQV (Mapped on the car). Made very good boost very early and was a beast to drive! :)


2004 FSTI, Modified 2006 Impreza, 1963 VW beetle. All on the road for once! Woo hoo! :)


#10 dnok

dnok
  • LocationElland West Yorkshire

Posted 20 July 2016 - 11:12 AM

Nice :) beast indeed. Still not convinced tho lol. Maybe it's something that can be mapped around hence your results.

I think trev is right with the spooling, perhaps that's more of a point when running one when not mapped to do so?

I will continue to do my digging and when I get closer to remap time I'll contact mr carr and ask his opinion. I have to ask you all these things though. Stuff like this keeps me awake at night! Lol. To say I'm a little obsessive is an understatement lol

#11 brownpantsracing

brownpantsracing
  • LocationBucks

Posted 20 July 2016 - 11:26 AM

When my Impreza was new and un-mapped I bolted a baileys dump valve straight to the car and made absolutely no difference to how the car drove at all. No difference in lag, no hesitation, no drop in boost etc.

 

Few years later I changed that for an HKS SSQV with still no re-map and made no difference at all, still drove 100% perfect with no issues at all. Then I ended up spending a fortune on the car and upgrading loads and had it re-mapped with the HKS SSQV fitted. Still drove great.

 

Before I sold the car I put the standard re-circulating dump valve back on and never had it re-mapped. Still drove perfect with no differences.

 

Realistically changing to VTA should make little to no noticeable difference and should cause no ill effects in reality.


2004 FSTI, Modified 2006 Impreza, 1963 VW beetle. All on the road for once! Woo hoo! :)


#12 dnok

dnok
  • LocationElland West Yorkshire

Posted 20 July 2016 - 12:15 PM

Well I don't know what to say to that. Definitly made a very noticeable negative impact on the foz and upon googling I've found many posts stating th same on subarus.

Did I do something wrong? Should I be blocking off anything else other than the pipe that runs directly to the turbo? Thanks for making me more confused than ever lol

#13 brownpantsracing

brownpantsracing
  • LocationBucks

Posted 20 July 2016 - 12:34 PM

I've also heard of people having running issues after fitting a VTA dump valve, you're not isolated. If you want one I'd suggest buying a decent one then fitting before the car gets mapped. In theory your mod should have worked. All you needed to do was block the return pipe back to the system and leave the return flange from the dump valve open. I used to run a recirculating dump valve years gone by on one of my other cars in this way with no effect. All I can think was the ECU was retarding something. Very odd.


2004 FSTI, Modified 2006 Impreza, 1963 VW beetle. All on the road for once! Woo hoo! :)


#14 dnok

dnok
  • LocationElland West Yorkshire

Posted 20 July 2016 - 12:37 PM

Great my ECU is retarded :( lol why are you selling the hks then? Have you already mentioned why lol. Rushing about like a nutter as usual

#15 brownpantsracing

brownpantsracing
  • LocationBucks

Posted 20 July 2016 - 12:45 PM

Sold the Impreza, so took it off and put the Impreza back to standard. I've decided to leave the Forester with the standard DV for now, so the HKS is up for sale! :)


2004 FSTI, Modified 2006 Impreza, 1963 VW beetle. All on the road for once! Woo hoo! :)


#16 dnok

dnok
  • LocationElland West Yorkshire

Posted 20 July 2016 - 12:59 PM

Well I've just checked that I have everything plumbed up properly. Boost pill (finally found the thing) is in the correct place, all lines look undamaged and tightly sealed etc so I don't understand it. Maybe it's an ECU thing, something different in how the foz one and the impreza one works? God only knows I just know I didn't dream the poor performance. I know the butt duno isn't always accurate but can't ignore the crap running, bogging, near stalling. Shame. I'd pull the trigger on the hks but until I wrap my head round this it's money I could spend elsewhere unfortunately. You should plumb up the hks to the foz and report back with your findings :)

#17 brownpantsracing

brownpantsracing
  • LocationBucks

Posted 20 July 2016 - 01:11 PM

How did you plug the large boost return pipe when you did it? Did you use a correctly sized bung and ensure it was sealed? I'm wondering if there was a slight boost leak on the system somewhere.

 

Forester and Impreza are the same beast with no difference in this area.

 

Very strange.

 

I'm sure the Foz will still run perfectly with the HKS fitted. The Impreza did so should not cause a problem on the Foz.


2004 FSTI, Modified 2006 Impreza, 1963 VW beetle. All on the road for once! Woo hoo! :)


#18 mrmarc

mrmarc

Posted 20 July 2016 - 02:17 PM

I've got a collins performance DV on my forester thats coming off soon.
Will be up for grabs if interested, no running issues at all.
It came with the car and I'm refitting the original part back on as I'm not really a fan of the noise

#19 dnok

dnok
  • LocationElland West Yorkshire

Posted 20 July 2016 - 05:13 PM

How did you plug the large boost return pipe when you did it? Did you use a correctly sized bung and ensure it was sealed? I'm wondering if there was a slight boost leak on the system somewhere.
 
Forester and Impreza are the same beast with no difference in this area.
 
Very strange.
 
I'm sure the Foz will still run perfectly with the HKS fitted. The Impreza did so should not cause a problem on the Foz.


I had a bung of a nice snug fit and used the standard Subaru pipe clip. Maybe the pipe clip didn't grip enough I suppose its possible. I've bought a very slightly bigger bung today which will take some forcing in and a good strong jubilee clip so I'll have another go and report back :)

#20 dnok

dnok
  • LocationElland West Yorkshire

Posted 20 July 2016 - 05:15 PM

Check out the two salesman lol. If I decide to go this route I'll probably go hks mrmarc but thank you for letting me know bud :)




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