Brand new DISA - suspicious flap operation

[Adi]

Hi ZHP Family,

Please help me out. I have just purchased a brand new DISA from BMW which arrived yesterday. The first thing I did was test the flap operation. The normal test where you close the flap with your fingers, and cover the one little air hole and see if the flap remains mostly closed is fine. However, whilst doing this test I noticed that if I close the flap with my fingers (while not covering the hole), when i release it, it does not return 100% to the open position - I have to help it.


https://youtu.be/Br8dUTpBGH0

As you can see in the video, if I partially close the flap, its fine - it springs back 100% everytime. But if I FULLY close the flap, you can see it doesn't want to spring back 100%.

I went to BMW today, and they said it's nothing to worry about and that once its installed and under vacuum it will work correctly.

This doesn't make sense to me, as when it is under vacuum, the flap will CLOSE, not open. So I am not convinced, as the purpose of the spring mechanism is to open the flap when its NOT under vacuum.

I am not sure how to argue this with BMW. Please share thoughts on whether this part is right or defective.

Thanks
Adrian

[johnrando]

I'd return it and get the G.A.S. DISA which remedies the flaw in the OEM DISA.

Sent from my SM-G955U using Tapatalk

[Vas]

I'd return it and get the G.A.S. DISA which remedies the flaw in the OEM DISA.

Sent from my SM-G955U using Tapatalk

Will they ship to South Africa?

[Adi]

Will they ship to South Africa?

Well, yes. But that makes it cost prohibitive. I just want to know if I should fight this battle. And it will be a battle with my local dealer because they ordered it in from Germany.

[Adi]

So I reached out to a few US parts shops for advice. Here were the useful responses:

FCPeuro:
"Thanks for contacting FCP Euro!

We have three of these units in stock and two out of three acted just like this one. I feel like this is normal until the unit is worn in. I apologize for any concern on this matter.

I'm here to help with any further questions or concerns!"

G.A.S.
"That can be normal. It's the result of the membrane cup getting folded
inside when you force the movement from the flapper. The only real way to
test is to suck on the vacuum hole that you cover when doing the vacuum
test. If the flapper returns normally when actuated that way you are fine."

Bavarian AutoSport
"It is our experience with several thousand Disa valves that this " test " is not an accurate way to test Disa valves , We have tested several for function and have come come to the conclusion that Disa valves that fail the "internet test" can and do in fact function correctly.
We are currently producing a blog video to better explain this and to "debunk" the internet test. how ever do to scheduling it will be a few months before we release this video."

I think BavAuto were mistaking my issue for the normal flap operation test where you cover the hole to see if the flap stays closed under vacuum.

I have asked my mechanic to perform a bench test on the unit as per G.A.S. recommendation. The test is like this:

https://youtu.be/pg6Jb3qEYvM?t=136

[Adi]

My shop tested the DISA as described above, and it's fine, so I'm having it fitted.

Thanks for the input.