Stock Blow Off Valve Noise

[Yelbom15]

Hello,

When I bought the vehicle, the car would really get up around that RPM 2.5-7 but now I feel like it takes up to 3 or 4 and real steady. Not punchy.

Lately, it hasn’t been doing that. It sounds almost like a whistle when it lets off. And it’s almost random. I feel the pressure build…then release and then fully build almost like hesitation or something releasing it prematurely. Are the stock BOV known for any issues? 55,000 miles.

Someone recommended checking the symposer?

 

[Dialcaliper]

Yes, the stock diverter valve/BOV is not that durable, especially if you’ve added a tune and raised the boost level over stock, which is why the GFB “adapter” exists - making for a better seal but actuated by the stock valve. Otherwise, there are other choices for aftermarket DV/BOV as well. The stock valve may eventually start leaking when boost is too high for the solenoid to fully seal, or get “sticky” as it starts to fail

The stock valve is generally not very noisy as it is electronically actuated and moves very fast. It uses a direct solenoid and does not use a pressure diaphram like the typical BOV - the classic “gssh” noise of a traditional BOV is due to the slower opening of a spring diaphram valve and the “whooshing” of the air as it passes through before the valve is fully open.

 

[Yelbom15]

Would anyone have any recommendations? A complete bolt on that’s more built towards longevity and quality. I’m not really a fan of anything that has a chirp or loud unless it’s on a rally course. I’m seeing turbosmart a lot in forums and google.

 

[Dialcaliper]

I have the GFB DV+ and like it a lot. It uses the stock electronic BOV as a pilot actuator, so it behaves and sounds just like stock hit with a stronger seal. Also less complicated as it doesn’t require any extra vacuum hose routing.

 

[M-Sport fan]

Did you order a 'plumb back/recirculating' type valve?

Those are the ones which will make the least amount of R2D2 chirping, or PSSSHH type noises (all else; intake, filter, etc. used being equal) vs. a 'vent to atmosphere' type valve, if that is what you are wishing to avoid.

 

[Yelbom15]

@Dialcaliper And a lot cheaper. I just wish I knew what I was looking at with the GFB DV+. This still uses the stock blow off valve? Isn’t that what I’m trying to replace?

 

[Dialcaliper]

@Dialcaliper And a lot cheaper. I just wish I knew what I was looking at with the GFB DV+. This still uses the stock blow off valve? Isn’t that what I’m trying to replace?

It sandwiches between the stock valve and the port on the turbo. The brass plunger does the actual sealing, and it uses a “pilot” like a sprinkler valve - basically the pressure channel is reduced to a small hole to the boost side of the piston when the valve is closed, so the stock valve is only holding against a small amount of force/area under boost, with the pressure on both sides of the plunger being almost equal. When the stock valve actuates, it releases the pressure on the outside of the brass piston through the pilot hole, and boost pressure blows the piston open quickly. When the pilot closes, pressure on the piston is equalized and the stock valve plunger closes it easily.

Basically it works similar to a “mechanical” BOV, but instead of just tapping a line from the intake and using manifold pressure/vaccum to actuate the valve, it makes use of the stock solenoid and atmospheric pressure, so can actuate much faster - opening and closing based on the ECU/throttle sensor instead of waiting for pressure/vacuum to build up behind the throttle plate.

 

[Yelbom15]

@Dialcaliper I really appreciate that explanation. I couldn’t find much on YouTube nor Reddit. I had a MK6 TDI but didn’t dive too much into learning the system. Is there any reason why someone would go a whole new/upgraded BOV rather than this one?

Im really just looking for longevity and peace of mind that parts are built right and I won’t have to look back on it once installed.

 

[Yelbom15]

@M-Sport fan I think I’ll go ahead with what @Dialcaliper is recommending. I started looking into more and more and just don’t have the proper knowledge on what I’m installing. And also don’t want to fabricate anything new!

 

[M-Sport fan]

For what it's worth, I also have the GFB DV+ installed now for about 6 years without one single problem or hiccup, at all.

A much bigger turbo than factory, running more boost pressure and pushing more air volume might be the only reasons to 'upgrade' from the GFB setup, as long as you do not want or demand all of that ancillary noise.

 

[Yelbom15]

Still waiting on the GFB DV+ to arrive. I also went ahead with a symposer delete by whoosh as well since they’re doing free shipping.
I hope this fixes it! Before, a second gear pull felt like a gradual climb and then BOOM…boost and torque steer.
Now it’s just a gradual climb rather than a hit. Checked all the clamps and what have you.

 

[Sam4]

Still waiting on the GFB DV+ to arrive. I also went ahead with a symposer delete by whoosh as well since they’re doing free shipping.
I hope this fixes it! Before, a second gear pull felt like a gradual climb and then BOOM…boost and torque steer.
Now it’s just a gradual climb rather than a hit. Checked all the clamps and what have you.

Save everything in case of visual emissions testing!

 

[Yelbom15]

I went ahead and installed the symposer delete plug and really confused. I assumed it was mostly a placebo effect but didn’t think it would be that big of a result. To the point that I may keep the DV aside. Would the symposer cause that bad of a leak? I’m opening it up to see what’s going on.

I’ve seen a couple comments stating those two clamps aren’t all that great with holding pressure. But I’m stock so I’m not sure if I fall into that category.

 

[Yelbom15]

Night and day difference. Thank you guys.