Oh no...Not another BOV thread

dallasjhawk

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All this talk about BOVs when we should be talking about whether the available upgraded BPVs are a performance upgrade. Forge Motorsport and Boomba both make full recirculating BPVs. There's absolutely no need for a BOV that vents to atmosphere but there could be a use for an upgraded BPV.
No use, the factory valve has been shown to work up to 30+ psi. And those aftermarket valves can have different spring rates than the stock valve causing issues

BOV.jpg





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Static_Awesome

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I'm gonna stir this pot a little:

1) What if you're using VTA and not replacing springs? As in, a plate? Would the only issue be .1-.5 seconds of richness between shifts, doing harm to your cats and possibly diluting oil?

2) Doesn't rev-hang delete cut off air, putting more fuel than air that's already in the system? I noticed equally rich conditions with rev-hang delete. Well, maybe not EQUAL but close.
 

KingOfBrussels

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No use, the factory valve has been shown to work up to 30+ psi. And those aftermarket valves can have different spring rates than the stock valve causing issues

BOV.jpg
I agree with most of what DRob says here. But he's only talking about part of the picture with aftermarket BPVs, i.e. the spring.

The other part he doesn't talk about is the stock BPV uses a diaphragm valve while the Forge Motorsport and Boomba BPVs use piston valves. A diaphragm valve has a (usually rubber) diaphragm that creates the seal when the valve is closed. A piston valve uses a solid piston (metal in this case) to completely block off the path of whatever's trying to flow through the valve.

s5QSy-o1zdz7hFJ2eMF3_GmJ3t8LvN_r9TNaJmEx7eC0H2-COQ.png


Piston-Valve1.jpg


I'm not a mechanical engineer, but here's a good explanation of the differences between diaphragm and piston valves: https://control.com/forums/threads/piston-vs-diaphram-control-valve.29708/

If you look at most of the information about diaphragm valves, the seal they create is more prone to leaking the more pressure they're trying to hold. Piston valves do not have these issues with pressure.

Hypothetically speaking, the the stock BPV diaphragm valve could be generally working fine, but in certain situations might be bleeding off boost without being told to do so by the ECU, due to its potentially imperfect sealing at high pressure.

If that's the case, then there could be gains to be had from an aftermarket piston valve BPV that consistently holds boost except when absolutely needed.

Now, getting back to what DRob is saying here. He says to not mess with too stiff of a BPV spring. He did not say that all aftermarket BPVs come with too stiff of a spring.

Boomba doesn't say anything about their springs, but Forge does. The valve comes with the softest green spring and they offer other stiffer springs to pair with different boost levels.

https://www.forgemotorsport.com/Valve_Spring_Tuning_Kit--product--826.html

One would hope that the springs in these things are selected in such a way to not cause issues vs the stock BPV, but Forge offering several different springs gives me a bit more confidence that the softest couple spring options could be soft enough to not cause problems.
 

dallasjhawk

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I agree with most of what DRob says here. But he's only talking about part of the picture with aftermarket BPVs, i.e. the spring.

The other part he doesn't talk about is the stock BPV uses a diaphragm valve while the Forge Motorsport and Boomba BPVs use piston valves. A diaphragm valve has a (usually rubber) diaphragm that creates the seal when the valve is closed. A piston valve uses a solid piston (metal in this case) to completely block off the path of whatever's trying to flow through the valve.

s5QSy-o1zdz7hFJ2eMF3_GmJ3t8LvN_r9TNaJmEx7eC0H2-COQ.png


Piston-Valve1.jpg


I'm not a mechanical engineer, but here's a good explanation of the differences between diaphragm and piston valves: https://control.com/forums/threads/piston-vs-diaphram-control-valve.29708/

If you look at most of the information about diaphragm valves, the seal they create is more prone to leaking the more pressure they're trying to hold. Piston valves do not have these issues with pressure.

Hypothetically speaking, the the stock BPV diaphragm valve could be generally working fine, but in certain situations might be bleeding off boost without being told to do so by the ECU, due to its potentially imperfect sealing at high pressure.

If that's the case, then there could be gains to be had from an aftermarket piston valve BPV that consistently holds boost except when absolutely needed.

Now, getting back to what DRob is saying here. He says to not mess with too stiff of a BPV spring. He did not say that all aftermarket BPVs come with too stiff of a spring.

Boomba doesn't say anything about their springs, but Forge does. The valve comes with the softest green spring and they offer other stiffer springs to pair with different boost levels.

https://www.forgemotorsport.com/Valve_Spring_Tuning_Kit--product--826.html

One would hope that the springs in these things are selected in such a way to not cause issues vs the stock BPV, but Forge offering several different springs gives me a bit more confidence that the softest couple spring options could be soft enough to not cause problems.
Ill stick with taking the word and testing of the person trying to make my car run correctly over the word of the person trying to push a product. I have not see one post anywhere here or on the facebook pages where someone complained that their stock valve failed. And we know if they were failing people would be talking about it all the time. Especially the sales guys :)
 

KingOfBrussels

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Ill stick with taking the word and testing of the person trying to make my car run correctly over the word of the person trying to push a product. I have not see one post anywhere here or on the facebook pages where someone complained that their stock valve failed. And we know if they were failing people would be talking about it all the time. Especially the sales guys :)
I'm not talking about the stock valve failing, I'm talking about it lightly bleeding off boost when it doesn't need to, and that the aftermarket BPVs might not do this. I have a feeling you did not attempt to read what I said above.
 

dallasjhawk

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I'm not talking about the stock valve failing, I'm talking about it lightly bleeding off boost when it doesn't need to, and that the aftermarket BPVs might not do this. I have a feeling you did not attempt to read what I said above.
I read it. What is the point of changing something to an aftermarket part that has no added value to me and is possibly worse for my car? The stock valve works as intended and I'm not going to mess with it. When I have had my logs looked at there is nothing going on to make you think its bleeding boost. Its amazing the stretches people go through to validate some purchase they made. Hell I am a ricer and immediately bought a BOV when they came out because I believed the sales. I swallowed my pride and put the stock one back on when my tuner showed me why it was awful in my datalogs. I naively thought he wouldnt know but nope. First log back he said do you have a bov. I trust @D-RobIMW and Vit know way more about this stuff than any of us.
 

gtman

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I'm not talking about the stock valve failing, I'm talking about it lightly bleeding off boost when it doesn't need to, and that the aftermarket BPVs might not do this. I have a feeling you did not attempt to read what I said above.
Just so members here aren't getting confused with your terminology, the stock unit is a BPV. The aftermarket ones we are discussing are generally BOV's which vent to atmosphere.

I trust @D-RobIMW and Vit know way more about this stuff than any of us.
Absolutely. Those guys have no reason to diss BOV's other than the fact they've seen the ill effects from them.

Here's the thing. No one is buying a BOV for performance benefits. It's a sound thing. If people make an educated decision to ignore the fact that they might cause problems, so be it. It's their car. Personally I wouldn't touch one with a 10 foot pole.
 
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KingOfBrussels

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I read it. What is the point of changing something to an aftermarket part that has no added value to me and is possibly worse for my car? The stock valve works as intended and I'm not going to mess with it. When I have had my logs looked at there is nothing going on to make you think its bleeding boost. Its amazing the stretches people go through to validate some purchase they made. Hell I am a ricer and immediately bought a BOV when they came out because I believed the sales. I swallowed my pride and put the stock one back on when my tuner showed me why it was awful in my datalogs. I naively thought he wouldnt know but nope. First log back he said do you have a bov. I trust @D-RobIMW and Vit know way more about this stuff than any of us.
You don't know that an aftermarket BPV, not BOV, won't make a performance improvement. You've copied and pasted someone who knows more about this stuff than you saying why it might be a problem. I've explained how they might, in theory, make a performance improvement.

The amount of boost that a less-than-perfect seal in the stock BPV might bleed off is not something that would show as a boost leak in a log like an atmospheric BOV. The BOV is dumping a whole bunch of charge air to the atmosphere. A slightly leaky BPV is letting a small amount of charge air recirculate back into the intake before the turbo. It's much more subtle.

Only way to find out for sure is to test stock and aftermarket BPVs to see if one makes more power. Until then this is all just speculation.

I don't have an aftermarket BPV on my car so spare me this nonsense about jumping through hoops to justify a purchase.
Just so members here aren't getting confused with your terminology, the stock unit is a BPV. The aftermarket ones we are discussing are generally BOV's which vent to atmosphere.
I'm saying BPV because I'm talking about aftermarket recirculating BPVs that recirculate the blown off air just like stock. The difference as I described above is they have piston valves instead of the stock BPV's diaphragm valve.

BOV = yep probably bad

BPV = maaaaybe it'll make an improvement, let's find out
 

Static_Awesome

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I think it's the opposite: Aftermarket BPV bad, BOV less bad.

Both bad, but I think the BOV is as bad as RevHang delete based off logs. I'd like to see log comparisons of RevHang delete vs a VTA BOV!
 

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What if a 1.5t is pushing say 1000hp where stock bov theoretically could leak boost, would it be good in that scenario?
I mean even for any setup, there has to be a workaround for any ill results from a bov it’s not impossible......
Right????

The inner engineer in me says there must be a solution but idk where is start.
 

dallasjhawk

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The amount of boost that a less-than-perfect seal in the stock BPV might bleed off is not something that would show as a boost leak in a log like an atmospheric BOV. The BOV is dumping a whole bunch of charge air to the atmosphere. A slightly leaky BPV is letting a small amount of charge air recirculate back into the intake before the turbo. It's much more subtle.
Im quoting someone who has literally tuned thousands of these cars and if he saw an issue with the stock valve he would say so. Again why would you replace something that works perfectly fine with something that a sales guy is trying to sell you? There isnt going to be a performance gain made from changing valve. Im not sure why you are arguing this. Maybe you're a sales guy or work for some company making these valves.
 

KingOfBrussels

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Im quoting someone who has literally tuned thousands of these cars and if he saw an issue with the stock valve he would say so. Again why would you replace something that works perfectly fine with something that a sales guy is trying to sell you? There isnt going to be a performance gain made from changing valve. Im not sure why you are arguing this. Maybe you're a sales guy or work for some company making these valves.
I'm trying to not be a dick to you, but you're testing my patience. I won't go round and round in circles with you when you clearly aren't interested in trying to understand what I've been saying.
 

dallasjhawk

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I'm trying to not be a dick to you, but you're testing my patience. What I won't do is go round and round in circles with you when you clearly aren't interested in trying to understand what I've been saying.
you can do whatever you want. There is still nothing wrong with the stock bpv as shown by literally zero people posting issues with them and zero tuners talking about leaking valves. The only people who talk about them in an negative light are people who have a product to sell to replace one. End of Story. FYI, I have a v2, I monitor and datalog all my drives. Until you can come at me with actual evidence of any bleed off that wasnt requested by the ECU, or a respectable tuner brings info to light, you're right, there is no reason to round and round in circles with yo when you clearly arent interested in understanding what I've been saying
 

dallasjhawk

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Some forums have oil threads... we've got this. :rofl:
Oh we had the oil thread, it was like the first big debate on this website until it got so bad the admins finally locked it haha
 

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