DISA Valve Video

[Mtnman]

So, for you familiar with the DISA. History- i have been having a power dip (very bad one) at 4000rpms. It lasts until 5-5500 most times. Sometimes it fluctuates (like the power band is riding a wave) sometimes its just a 20% power drop for the whole time. Also, it happens when its hot outside, and only happens about 40% of the time. I have taken it to BMW to check coding...(wasted 60 bucks, but at least they didnt hit me for a full 100) and all my software is up to date. im thinking it could be the DISA valve, because that is where the valve is supposed to open. I took the valve off tonight. the butterfly is operational, but sometimes make a very strange sound when it is open. See video. This valve should make no noise. What you hear i dont think should be happening. What do you DISA pros think? it seems to match the "doesnt happen every time". Try to ignore the out of shape shirtless man holding the disa.

[Oli77]

Stop playing with your DISA Mtnman!

[Hornung418]

The DISA is vacuum actuated, I'm pretty sure both my M52TUB28 and M54B30 DISAs make the popping noise. Air being forced through a small hole into a large opening should create that sound.

Is there a part number listed on your DISA unit? I would compare with RealOEM to see if you are eligible for an updated unit, which should be included with the Software Update as per the SIB 12 08 05, but that one is out of date, and the Dealer will refer you to SIB 12 17 05.