[DrLeoMarvin]

So I just recently installed a VRSF Charge Pipe and Tial BOV, other mods include JB4, DCI, and BMW PE. I seem to be getting inconsistent flutter when shifting at lower boost (2-4psi).

I've done extensive searching but can't seem to find a definitive answer as to whether this is acceptable or not. It never happens while on the throttle or at high/no boost so I can't imagine it causing any damage other than being an annoyance.

Any input is welcome!

[einbruch10]

is the flutter coming from the BOV? if so try adding a spacer in the BOV.

[DrLeoMarvin]

Originally Posted by einbruch10

is the flutter coming from the BOV? if so try adding a spacer in the BOV.

The only part that has changed since the flutter started is the charge pipe and BOV. The way I understand BOV's adding a spacer would only make the sound worse as that is comparable to stepping up a spring size. If anything I would want to go down to a 10lb spring to allow the BOV to open easier under vacuum.

[MarcusE92]

I am looking into doing the same exact combo and read that a 7lb spring was actually needed to correctly operate in our car.

[DrLeoMarvin]

Originally Posted by MarcusE92

I am looking into doing the same exact combo and read that a 7lb spring was actually needed to correctly operate in our car.

That sounds way too low of a spring. Most people run an 11lb spring while some step down to 10 or even 9 but I've never heard of anybody running a 7lb.

Even though I don't think any damage will come from a bit of flutter at low psi I'll probably try running the 1/4" vacuum line straight from the BOV to the manifold instead of using the adapter to the factory line. If that doesn't help possibly a 10lb spring.

[ferocity02]

11psi spring is common for N54. I tried it and I got a lot of flutter. I went down to a 10psi spring and it helped a lot, but there is still some flutter on low boost. High boost is perfect. It is not open at idle.

These things also need time to "break in". Give it a few weeks before deciding to change the spring.

[DrLeoMarvin]

Originally Posted by ferocity02

11psi spring is common for N54. I tried it and I got a lot of flutter. I went down to a 10psi spring and it helped a lot, but there is still some flutter on low boost. High boost is perfect. It is not open at idle.

These things also need time to "break in". Give it a few weeks before deciding to change the spring.

I was more interested in making sure that the low psi flutter wasn't causing any damage, which I believe it's not since it's closed at idle and not fluttering on higher boost shifts. If no damage is occurring it's simply a matter of personal preference on the annoyance level.

[BeastMode335i]

Don't know much about the issue, but OP your name is pretty hilarious lol.. Great movie haha...!

[335NJ]

Check vacuum lines and ensure they're all in good shape, mainly the one that connects to the BOV.

I believe they ship with an 11lb spring, however Tony@VTT suggests a lighter spring to eliminate the flutter. I forget the exact one, but it was about 8lbs.

[ferocity02]

For Tial Q they have 12, 11, 10, 8, and 6 psi springs for turbo applications.

I might try an 8psi spring but it will definitely be open at idle, which isn't a problem if air is coming out. But I'm worried that it might suck air in on overrun or something.

[Tiago@VRSF]

10 is the lowest I'd ever run on this car. If you need anything lower than a 10 psi spring, you have vacuum leaks. We've helped dozens of customers who require a "lower" spring and after a boost leak test they find out they have cracked vacuum lines or broken nipples on the vacuum canisters. Defective solenoids, poorly coupled connections, lack of o-ring on the BOV, TMAP or throttle body could also cause leaks

[BMDoublYou]

OP are you using the stock 1/8" vac line from the manifold, Tial states a dedicated 1/4" is required, curious as I will be throwing on my CP and Tial next week

[DrLeoMarvin]

Originally Posted by BMDoublYou

OP are you using the stock 1/8" vac line from the manifold, Tial states a dedicated 1/4" is required, curious as I will be throwing on my CP and Tial next week

VRSF provided a 1/4" line and a 1/4" to 1/8" adapter that I'm using as the provided 1/4" wasn't long enough to reach from the BOV to the plastic nipple on the manifold. I'm thinking of going out and buying one that is long enough and removing the stock line from the picture, but I'm sure the plastic nipple is the restriction at that point.

[335NJ]

Originally Posted by DrLeoMarvin

VRSF provided a 1/4" line and an 1/4" to 1/8" adapter that I'm using as the provided 1/4" wasn't long enough to reach from the BOV to the plastic nipple on the manifold. I'm thinking of going out and buying one that is long enough and removing the stock line from the picture, but I'm sure the plastic nipple is the restriction at that point.

Mine broke, so I had a local shop drill & tap a 1/4 x 1/8 NPT brass vacuum fitting. BOV sounds much more "responsive", per se.

[DrLeoMarvin]

Originally Posted by 335NJ

Mine broke, so I had a local shop drill & tap a 1/4 x 1/8 NPT brass vacuum fitting. BOV sounds much more "responsive", per se.

That would be ideal but I'll try without that first. If I end up going to a shop for that I'll have them do a vacuum test too just to make sure.

So just to be clear, having some BOV flutter when shifting at partial throttle and say 2-4psi won't cause any harm? Just more annoying than anything?

[ferocity02]

Originally Posted by 335NJ

Mine broke, so I had a local shop drill & tap a 1/4 x 1/8 NPT brass vacuum fitting. BOV sounds much more "responsive", per se.

I am thinking about doing this, or at least adding a second fitting to the manifold.

[max_k20]

I'm having some flutter issue as well (randomly on low boost partial throttle as well) but not very often but yes I do sometimes. I am using the hose provided by ER on the stock nipple (not sure on sizing but pretty sure it's 1/4). It's been dointg it a lot less (still happen rarely from time to time) since I removed my boost gauge that was teed in the stock hose and connected the bov directly to the manifold (via the stock nipple). I too think the stock nipple is the culprit but not really looking to drill manifold (at least for now).

[///Mposter]

I had the same situation with low boost flutter and when I went to visually check the hoses, the 1/4" hose at the bov was trying to back itself off. I used a tie strap to hold it and figured that was it. Drove it again, still flutter. Was about to remove 1/8" hose and brass adapter by razor blade when I realized that the 1/4" hose inner diameter was a perfect fit over the 1/8" hose. So instead of using the razor to take the 1/8" off, I left the 1" of it on the manifold and slipped the 1/4" over it and I have not heard flutter since.